Autocrossers - need tire input - going WIDE, all around

[Gears for Brains]

I've just about got myself convinced that I can go 265 all-around with front fender rolling, front wheel spacers to dial in the offset, a little more slotting of the strut bracket holes, and as a backup, 5-10mm higher ride height with my 3/8" drop springs - Noltec makes polyurethane spacers for the front. If I add offset strut top bushings to the mix, 275 should be feasible.

So, I've been studying up on the tire options. This is for SCCA solo class STU - minimum treadwear rating of 140...no R-compound Hoosiers this time around. Here's what I find when I search Tire Rack. "Extreme Performance" is their top-dog rating, these are in bold, the others are "Max Performance" (and I skipped over some of the higher treadwear tires in this category to narrow it down a bit). Section widths have been adjusted for a 9" rim by the old rule of thumb: 0.4" section width change per 1" of wheel width. Section width comparisons (i.e. +8mm) are based on my current front tire, measured at 10.3"

265/40-17 (25.3-25.4" OD)
====================
Goodyear Eagle F1 Supercar: 220-AA-A, 29#, 10.5" section (+5mm), $299
Michelin Pilot Sport PS2:...... 220-AA-A, 25#, 10.5" section (+5mm), $244
That's right, two tires, ignoring closeouts with "fewer than two" availability...

275/40-17 (25.6-25.7" OD)
====================
Michelin Pilot Sport PS2: 220-AA-A, 26#, 10.7" section (+10mm), $288
Yokohama AVS Sport:... 180-AA-A, 31#, 10.8" section (+13mm), $209
BFG g-Force T/A KD:... 200-AA-A, 29# 10.7" section (+10mm), $255
Kumho Ecsta MX:........ 220-AA-A, 28#, 10.8" section (+13mm), $141
Falken Azenis RT-615:. 200-A--A, 29#, 10.6" section (+8mm), $141

265/35-18 (25.3-25.4" OD)
====================
Bridgestone Potenza RE050A PP:.. 140-AA-A, 28#, 10.6" section (+8mm), $244
Michelin Pilot Sport PS2:............. 220-AA-A, 25#, 10.5" section (+5mm), $304
BFG g-Force T/A KD:................ 200-AA-A, 28# 10.5" section (+5mm), $285
Bridgestone Potenza RE-01R.... 140-A--A, 29#, 10.5" section (+5mm), $256
Dunlop Direzza Sport Z1:.......... 200-A--A, 29#, 10.5" section (+5mm), $227
Kumho Ecsta MX:..................... 220-AA-A, 26#, 10.6" section (+8mm), $207
Yokohama ADVAN Neova AD07: 180-AA-A, 28#, 10.4" section (+3mm), $320
Falken Azenis RT-615:.............. 200-A--A, 29#, 10.5" section (+5mm), $213
I left out some Pirelli PZero's, Yokohama ADVAN Sport & AVS Sport (low stock), etc, so many choices in this size...

275/35-18 (25.6-25.7" OD)
====================
Bridgestone Potenza RE050A PP: 140-A--A, 29#, 10.7" section (+10mm), $257
Michelin Pilot Sport PS2:........... 220-AA-A, 27#, 10.7" section (+10mm), $316
Pirelli P Zero Rosso:................. 220-AA-A, 28#, 10.6" section (+8mm), $290
Dunlop Direzza Sport Z1:....... 200-A--A, 31# 10.8" section (+13mm), $228
Kumho Ecsta MX:.................. 220-AA-A, 27#, 10.9" section (+15mm), $205
Falken Azenis RT-615:........... 200-A--A, 29#, 10.6" section (+8mm), $199
Yokohama ADVAN Sport & AVS Sport were again in low stock mode.

It looks like 265/35-18 is the "sweet spot" for tire selection, and it's obviously less of a challenge to squeeze in a 265 than a 275. I'm not having quite as much luck with 18x9 lightweight wheels as with 17x9, but I've got something cookin' :secret:

Please post up your feedback on any of these tires. If there's something else I should look at, tell me about it (including where you get 'em). I must be crazy spending so much time putting this together, help make it a worthwhile with lots of comments!

[r0nd3L]

For my next tire I'm most likely going with RE-01r. They are very grippy tires and last decently long time. In our VW/Audi club, top Autoxer uses them and swears by them.

[psu goat]

I used the RE-01R's this past season and they're pretty darn amazing! I also went to the SCCA Solo II Nationals in Topeka, Kansas in September (co-drove in FS in my friend's Camaro) and I would say the majority of people in all of the ST* classes switched to the 01R's.

There were still cars using the Yokohama Advan Neova's, and a few with the Falken Azenis RT 615, but the 01R's proved to be the fastest tire. So if you're concerned about the absolute best performance for street tires in auto-x, I would say the best two choices are the 01R and the Advan Neovas.

I also plan on switching to the STU class this upcoming season, and I think I'm going to try out the Dunlop Direzza Sport Z1's since they're now SCCA legal for this year. A few of the Evo's have been using them in STU at the first few events in California and they seem to be even a bit faster than the RE-01R and for less money. Tirerack did a test between them and they gave some pretty impressive results in the wet and dry.

Hope that helps!

[puddy46]

I used the RE-01R's this past season and they're pretty darn amazing! I also went to the SCCA Solo II Nationals in Topeka, Kansas in September (co-drove in FS in my friend's Camaro) and I would say the majority of people in all of the ST* classes switched to the 01R's.

There were still cars using the Yokohama Advan Neova's, and a few with the Falken Azenis RT 615, but the 01R's proved to be the fastest tire. So if you're concerned about the absolute best performance for street tires in auto-x, I would say the best two choices are the 01R and the Advan Neovas.

I also plan on switching to the STU class this upcoming season, and I think I'm going to try out the Dunlop Direzza Sport Z1's since they're now SCCA legal for this year. A few of the Evo's have been using them in STU at the first few events in California and they seem to be even a bit faster than the RE-01R and for less money. Tirerack did a test between them and they gave some pretty impressive results in the wet and dry.

Hope that helps!

Why am I not surprised to find you in this thread? :gr_jest:

Has there been any more results from the Dunlop Z1's, such as wear ( I know it's still real early in the season) or how heat build-up affects the grip for the later runs?

[psu goat]

I should also add that I'm looking to buy the BMW CSL replica's in 18x8.5 40et front and 18x9.5 45et rear.

Gears for Brains, since you have some very nice looking wide BBS wheels from reading your sig, I was wondering if you could answer this for me. I'll be upgrading to the full Pedders Track II 0" drop suspension (as long as I can use all of those bushings in STU...need to read the rulebook more) with Hotchkis bars front and rear. I already have the Pedders GSR struts and Big Bore rear shocks.

Do you think I would be able to fit 255/35/18's in the front and 275/35/18's in the rear with these wheels and their offsets? I'm not sure if there will be enough room in the front, but my current 17x8 40et wheels and 245/40/17 tires have tons of clearance from the strut, so I'm hoping a 255 could fit with about -1.2 degrees of camber.

I've read that people have been able to fit 275/35/18 toyo's on the 18x9.5 CSL replicas with the rear fenders rolled or cut, but the Dunlop Z1's have a larger section width than the toyo's, so I'm not sure. I'm going to try and have the CSL wheels milled 3mm to make them a 48mm offset in hopes of having enough clearance. I'd like to just cut the fender lips, but the rulebook states that you can only roll fender lips in STX and STU classes :(

Do you have your fenders rolled and was it difficult? I'm hesitant of the paint cracking if I have a local shop do this. Finally, do you think my goals of 255/275 with these wheels are realistic? I'm hoping that with 0" drop springs, the big bore rear shocks, the rear swaybar, and proper bushings, that the rear end shouldn't squat as much and hopefully the fenders won't rub.

Sorry for taking your thread off track, now back to tires! :)

[psu goat]

Why am I not surprised to find you in this thread? :gr_jest:

Has there been any more results from the Dunlop Z1's, such as wear ( I know it's still real early in the season) or how heat build-up affects the grip for the later runs?

Hmmm, maybe because I'm just a little obsessed with autox like you? ;)

I've read mixed results on heat build-up on different forums so far. Some say they handle heat great like the 01R's do, others say they get a little greasy like the Azenis RT-615.

The Z1's are 10/32nd's at full tread depth, just like the 01R's, but they have a 200 treadwear rating instead of 140, so in theory, they should wear a little better. But treadwear ratings are independent between different manufacturers, so a 140 rating with one company could be equivalent to a 200 rating with another company...at least from what others have told me.

If Bridgestone made the RE-01R in 275/35/18, I would most likely stick with them this season, as I was very happy with them last year. I just need to get clarification from someone that I can fit a 275/35/18 in the back before I buy some tires. haha.

And if you're wondering why I'm going from 17 to 18 inch wheels, I eventually want to get bigger rotors and maybe some bigger calipers for better stopping power :)

[puddy46]

Hmmm, maybe because I'm just a little obsessed with autox like you? ;)

I've read mixed results on heat build-up on different forums so far. Some say they handle heat great like the 01R's do, others say they get a little greasy like the Azenis RT-615.

The Z1's are 10/32nd's at full tread depth, just like the 01R's, but they have a 200 treadwear rating instead of 140, so in theory, they should wear a little better. But treadwear ratings are independent between different manufacturers, so a 140 rating with one company could be equivalent to a 200 rating with another company...at least from what others have told me.

If Bridgestone made the RE-01R in 275/35/18, I would most likely stick with them this season, as I was very happy with them last year. I just need to get clarification from someone that I can fit a 275/35/18 in the back before I buy some tires. haha.


Thanks for the info, good stuff to know. I really glad to hear the treadwear is higher. I don't know if my play tires will be on the car the full summer, or just at events yet. Either way, the Dunlop's seem to be a winner so far. (Gears for Brains and others, please don't take this comment as advise, I'm bench racing on this one).

And if you're wondering why I'm going from 17 to 18 inch wheels, I eventually want to get bigger rotors and maybe some bigger calipers for better stopping power :)

Threadjack: Bigger? oh my. If and when this happens, let me know.

Gears for Brains, sorry for crapping on your thread, but a boy's gotta know things like this :angel:

[Riddlefox]

I used the RE-01R's this past season and they're pretty darn amazing! I also went to the SCCA Solo II Nationals in Topeka, Kansas in September (co-drove in FS in my friend's Camaro) and I would say the majority of people in all of the ST* classes switched to the 01R's.

There were still cars using the Yokohama Advan Neova's, and a few with the Falken Azenis RT 615, but the 01R's proved to be the fastest tire. So if you're concerned about the absolute best performance for street tires in auto-x, I would say the best two choices are the 01R and the Advan Neovas.

Here's the results (scroll down to page 31 for STU):
http://www.scca.com/documents/resultfiles/5632_Fin al%20Results%2011.14.pdf

The Advan Neovas took 1st - 6th place in STU, but those were all STis or Evos. An M3 took 7th on the RE01Rs.

The Neovas are faster than the RE01Rs, but they're a lot more expensive.

Personally, I'm excited about the Dunlops mentioned before. They're less expensive than the RE01Rs but look as if they can perform on the same level. It seems to be a really good sweet spot in price and performance for sure, and I've even heard its good in the wet too. Could be a great double duty (daily driver/autox) tire.

[psu goat]

Thanks for clarifiying that Riddlefox! I just remember seeing all the STS and STS2 cars on the 01R's then I guess. I'd like to try the Neova's but they're just too pricey for the big heavy gto to wear them away too fast :) Another thought, do you think a properly set up GTO for STU would have a snowballs chance of being competitive at a National level against the EVO, STi, and e36 M3? Everyone tells me NO, and I'm assuming they're right. Right now, I just want to have more fun with the car, but I do plan on taking it to Nats in STU just to see how it does, even though it won't be anywhere near a fully-prepped car this season.

[Riddlefox]

PSU, anything's possible, but I doubt it. The GTO is a lot heavier, longer wheelbase, and so on. Further, there's so many more people running STis, Evos, M3s that there's that much more knowledge to build off of because there's more people trying things. Plus, there's some pretty hardcore people driving those cars and I don't know how many of them are driving GTOs.

It'd be quite an upset though if you guys can pull it off!

[mooninitesunite]

T/A KD is an amazing tire, and I've heard great things about the RE-01R

[PreludetoaGTO]

Now here's a thread right down my alley. (Having run in STS for the past 7 years)

Here's roughly how the tires rank, fastest to slowest:

Bridgestone RE-01R/Yokohama Advan Neova AD07
Falken Azenis 615 (you left them off your list)
Kumho Ecsta MX

Everything else is going to be quite a bit slower. I opted for the Falkens again this year, despite the supposed superiority of the Bridgestones. They're more then capable for local and even regional events, and I think ultimately they're only a few ticks slower than the Bridgestones (although this is a big difference in the hotly contested ST* classes).

Unfortunately I doubt the GTO would ever be a competitive autox'er. I always felt like I could really feel the wheelbase working against me. In sweepers the car is a joy to drive, but crank it down into a hairpin and I really would get a sense that this isn't what the car is for.

[Gears for Brains]

r0nd3L, psu goat, puddy46, Riddlefox, mooninitesunite - thanks for all the comments! An autocross friend of mine ran that same event summary showing all Yokohama and Bridgestone, but it's great to know that means Neova and RE-01R, from someone who was there. The Direzza Sport Z1 does look like a good performance/price value. I will be reading the Tire Rack test results with all these comments in mind. I don't need the absolute most competitive tire at this point, but as long as I'm getting dedicated auto-x tires I might as well buy good ones.

Conclusion so far: 18" = much, much better tire selection than 17"

I should also add that I'm looking to buy the BMW CSL replica's in 18x8.5 40et front and 18x9.5 45et rear.

Gears for Brains, since you have some very nice looking wide BBS wheels from reading your sig, I was wondering if you could answer this for me. I'll be upgrading to the full Pedders Track II 0" drop suspension (as long as I can use all of those bushings in STU...need to read the rulebook more) with Hotchkis bars front and rear. I already have the Pedders GSR struts and Big Bore rear shocks.

Do you think I would be able to fit 255/35/18's in the front and 275/35/18's in the rear with these wheels and their offsets? I'm not sure if there will be enough room in the front, but my current 17x8 40et wheels and 245/40/17 tires have tons of clearance from the strut, so I'm hoping a 255 could fit with about -1.2 degrees of camber.

I've read that people have been able to fit 275/35/18 toyo's on the 18x9.5 CSL replicas with the rear fenders rolled or cut, but the Dunlop Z1's have a larger section width than the toyo's, so I'm not sure. I'm going to try and have the CSL wheels milled 3mm to make them a 48mm offset in hopes of having enough clearance. I'd like to just cut the fender lips, but the rulebook states that you can only roll fender lips in STX and STU classes :(

Do you have your fenders rolled and was it difficult? I'm hesitant of the paint cracking if I have a local shop do this. Finally, do you think my goals of 255/275 with these wheels are realistic? I'm hoping that with 0" drop springs, the big bore rear shocks, the rear swaybar, and proper bushings, that the rear end shouldn't squat as much and hopefully the fenders won't rub.

Sorry for taking your thread off track, now back to tires! :)

I think you'll be OK replacing just about any bushing, as long as it doesn't become solid metal or a heim joint. Note to self: re-read rules thinking about Noltec offset top mount, it appears to have a spherical joint.

Your proposed front wheel & tire fitment should be no problem - mine is quite similar, but with 3/8" drop springs. You may need spacers to get that much camber. Slotting the strut bracket holes is OK in STU and works well for me. I can't be so definite about your plan for the rear - I had my wheels widened to 9.8" +52 primarily to bring the offset into the ideal range, plus it was nicely proportioned to the tire widths. I bought the Eastwood roller and "rolled my own". This isn't rocket science if you have a feel for working with metal, just take your time and use lots of heat. I did get some minor cracking that follows the arc of the fender lip, where the metal wanted to fold instead of roll with a decent bend radius. I believe that has to do with the spot welds - if they zig-zag across the lip, it reinforces the lip more than if they're in a straight line. Note that I have rear 1/2" drop springs with 12mm spacers, giving ride height of 591mm with 17's. I think you'll be able to make it work with rolling, OE height springs, and CSL wheels.

Food for thought:
1. After running my staggered setup, I'm looking at 265 or 275 all-around and rotatable.
2. Theory-wise, a lower CG will help you. I'm going to do my utmost to keep the car low. I may try a thinner spacer in the rear before it's all over.

I hope you take your GTO to the Nationals, that would be a nice jolt for all the STi and EVO enthusiats.

[Orkboyz]

I don't know how good they will be at Auto-X but I have some KDW-2 going on the car tomorrow for street use. I'm pretty much screwed when it comes to SCCA classing. My suspension puts me in STU but the Tires I prefer to run (Yokohama AO48) bump me into ESP where I do not stand a chance. Hell STU is competitive enough in this area with all the WRX STi.

I Prefer the NASA system of classing using a base class based on HP-weight then points assigned to modifications. With enough points you get bumped in class. And no PAX in NASA either.


In sweepers the car is a joy to drive, but crank it down into a hairpin and I really would get a sense that this isn't what the car is for.


Inducing a bit of understeer is your friend in those hairpin situations. There is a local guy that runs a 04 CTS-V and he always kicks ass. He runs if F Stock. Out of an average field of 125 cars he usually come in right around 40 on raw time and right around 25 in PAX. Also, I have seen him very rarely WOT while on course. He just finds the lines.

I pretty much suck at AutoX and when he is at an event I can usually tell how I'll do. My best run is usually 5 seconds behind him in raw time which usually puts me in the middle to 3/4 of the field. It also does not help that I am nowhere near consistent since I tend to experiment with lines while on course.

[dkrowner]

on the wheels,for light weight fikse is the way to go on that,sure u'll pay out u a-- but what don't cost big buck's with a gto

[PreludetoaGTO]

Inducing a bit of understeer is your friend in those hairpin situations. There is a local guy that runs a 04 CTS-V and he always kicks ass. He runs if F Stock. Out of an average field of 125 cars he usually come in right around 40 on raw time and right around 25 in PAX. Also, I have seen him very rarely WOT while on course. He just finds the lines.



Understeer or oversteer? The car already understeers pretty badly in those situations. I haven't spent quite enough time autocrossing the GTO to get the tire pressures dialed in. I'm moving back to the prelude this year anyways.

[psu goat]

I'd love to get some lightweight fikse or ccw 505a wheels with perfect custom offsets, but if I spend $2600+ just on wheels, my autox budget will be gone for the year :(

The 18x8.5 CSL replicas are 24 pounds and 18x9.5's are 24.5, which is still lighter than the stock 17's and 18's, but heavier than my current ASA's which are 21.2 pounds each and still aren't nearly as light as OZ's, CCW, Fikse, etc.

If I can find another set of 18's wheels with the widths as above that are lighter than the CSL's, are still somewhat affordable, and actually look nice, I'll buy 'em, but I really like the look of the CSL's :)

Edit: My buddy in an F Stock '94 LT1 Camaro Z/28 consistently pax'ed in the top 15 drivers and took 1st in FS at every Pittsburgh event but one this past season, and we have some really good drivers in the Pittsburgh region in my opinion. The other club we race in (non-SCCA) dictates street tires for Stock Classes, so we race FS at those events, and I beat him a few times this season to take 1st. I've never raced the GTO with R-Comps in FS, but it was competitive at a National level, as Bob who used to be on this forum trophied at Nationals with his. Now the Shelby GT showed up and dominates everything. haha.

[Gears for Brains]

There's one more parameter I should ask about...with my fairly novice skill level, a more "forgiving" tire would be better than the absolute fastest tire with a real abrupt breakaway...would that change the recommendations at all?

Here's roughly how the tires rank, fastest to slowest:
Bridgestone RE-01R/Yokohama Advan Neova AD07
Falken Azenis 615 (you left them off your list)
Kumho Ecsta MX
**edit**
Unfortunately I doubt the GTO would ever be a competitive autox'er. I always felt like I could really feel the wheelbase working against me. In sweepers the car is a joy to drive, but crank it down into a hairpin and I really would get a sense that this isn't what the car is for.

Well put - the size and mass work against us on tight courses. Much more fun when the courses are designed by CP drivers!

After more than one mention of the Falkens, I added them to the original post. Falken's website doesn't show the 18" sizes for some reason. Edge Racing gives weights, but 34# for a 265/35-18 seems very suspicious. Do you know where I could get the rest of the specs?

Inducing a bit of understeer is your friend in those hairpin situations.
**edit**
It also does not help that I am nowhere near consistent since I tend to experiment with lines while on course.

I was wondering about the "inducing understeer" part too...

Nothing wrong with experimenting and trying different lines. I've tended to go out and do the same thing over and over again, when I should be trying the alternate slalom entry, etc.

I'd love to get some lightweight fikse or ccw 505a wheels with perfect custom offsets, but if I spend $2600+ just on wheels, my autox budget will be gone for the year :(

The 18x8.5 CSL replicas are 24 pounds and 18x9.5's are 24.5, which is still lighter than the stock 17's and 18's, but heavier than my current ASA's which are 21.2 pounds each and still aren't nearly as light as OZ's, CCW, Fikse, etc.

OK, after several hits on the "lightweight wheel" teaser, here's the scoop: LTW Motorsports LTW-5 (I've also seen them called D-Force or something like that). It's a cast wheel, with the rim portion cold-worked by the MAT process, like Enkei NT03+M. Here's the good & bad news together:
17x9 +41 5x120 16.4# $260
18x9 +41 5x120 17.9# $300
I'm working with one of the LTW resellers to see if there's enough stock on the mounting pad to machine off 3-4mm. They also have 17x8.5 +40, 18x8.5 +40, and 18x9.5 +41, among others. I sure hope I can make this work, they seem like excellent wheels at a very good price.

[psu goat]

Wow, I was google searching two nights ago and I found that same wheel on a bmw forum and am thinking about it too! Please keep me updated on what you find out about the offsets on that wheel. I'm wondering how an 18x9 with a possible offset of 45mm would fit in the back...I would think a little better than an 18x9.5 45et.

[Riddlefox]

If I can find another set of 18's wheels with the widths as above that are lighter than the CSL's, are still somewhat affordable, and actually look nice, I'll buy 'em, but I really like the look of the CSL's :)

What about the Rota P45s being sold here? I just got a set, and they look very nice. They're lighter than the CSLs by a few pounds apiece, and they were well under a grand shipped.

I've heard the KDW-2s chunk pretty easily when pushed hard in corners.

[psu goat]

Once again, you rock Riddlefox! I just checked out that thread. These Rotas look like they'll work almost perfect with the 50mm offset for the rear, and 22.3 pounds for an 18x9.5 is pretty cool.

I wasn't crazy about the inward curve of the spokes on the rear wheel at first, but now I'm actually really liking the difference between the front wheels and back wheels. And the hyperblack finish looks amazing like on a lot of other wheels.

Do you think a 255/35/18 Dunlop Z1 (tirerack says 9" section width but that can't be correct - I'm thinking it's a 10" or greater section width) would fit ok on the 18x8 fronts without bulging on the wheel too much? Tirerack recommends an 8.5-10" wheel. With the 42et offset in the front, I would think the 255's may clear the front struts and still allow some negative camber too.

Gears for Brains, sorry for continuing to post off-topic, but autocross doesn't always get a lot of discussion on this forum, so it might be good to make this an all encompassing auto-x thread. If you want me to move the wheel discussions to another thread, just let me know :)

[TXRaider]

There's one more parameter I should ask about...with my fairly novice skill level, a more "forgiving" tire would be better than the absolute fastest tire with a real abrupt breakaway...would that change the recommendations at all?

Excellent question. I'm in the novice boat too and I'd like to know from those of you with more experience what your thoughts are on the tires mentioned here if there is any abrupt race tire like breakaway tendencies.

FWIW, I'm using the Falken RT 615's, mostly due to great price - and major novice level I'm at. But I've been very pleased and I really like the way these tires "talk" to me when they are pushed.

How do the RE-01's act on the limit?

[psu goat]

The 01R's are very predictable at the limit in my opinion, and they've worked quite well for me in the rain - I had almost a 2.5 second lead over the 2nd place car at one rain event last year, which is very uncommon for my region. Since the gto is a heavier car, they'll start to squeal to let you know when you're just about ready to push them too much...they're pretty quiet on smaller cars from what I've experienced, or maybe it's just my driving style ;) Once they start to oversteer, I don't really have too much trouble getting the car to snap back in line with some throttle modulation. I've tried to purposely push them too hard on some fun runs, and sometimes they surprise me and I realize I could've pushed harder during the timed runs. My best times of the day are typically during fun runs with a passenger riding along...I think it helps weight transfer better for me.

They supposedly have a slightly softer sidewall the the RT-615 or the Advan Neovas...I've never driven on either of these tires so I can't comment. I will say that I still run about 41psi in the front tires during at an event, and they still roll over some. I usually run 28-35 in the rear tires. They handle heat well for me, and will usually only jump up 1 psi or less in between runs.

I really have nothing bad to say about the 01R's at all except that I wish they made them in 275/35/18.

[dkrowner]

the fikse profil 10 rims i have cost just under $4500.00 shipped,and yes the cars handling felt better.i think it was one of the best up grades i made right after the aps tt system

[z28jeff]

Edit: My buddy in an F Stock '94 LT1 Camaro Z/28 consistently pax'ed in the top 15 drivers and took 1st in FS at every Pittsburgh event but one this past season, and we have some really good drivers in the Pittsburgh region in my opinion. The other club we race in (non-SCCA) dictates street tires for Stock Classes, so we race FS at those events, and I beat him a few times this season to take 1st. I've never raced the GTO with R-Comps in FS, but it was competitive at a National level, as Bob who used to be on this forum trophied at Nationals with his. Now the Shelby GT showed up and dominates everything. haha.

Come on now, be fair. You know I'm stuck with crappy Kumho SPT's, because Bridgestone (nor Falken, Yokohama, or Kumho for that matter) won't make those cheater street tires in any 16" size wider than a 225. (I need at least a 245). Had I been on REO1R's, things may have been different. :cool:
To add to this thread, Bridgestone has quickly taken over the top spot in the street tire wars. Not only because they offer a competitive tire, but also because of their support to the sport. They offer contingincy money at National events, and are usually on site to support their drivers. Hell, they threw a big catered dinner at Nationals for anyboby running their tires. But it's not all just good marketing. They do offer a great product. However, I don't believe the Bridgestones are much (if any) faster than the Falkens or Yokohamas. But they do recover better. By that I mean if you overdrive a Falken, you have to lift the throttle and slow the car to get it to regain grip. Where the Bridgestone will recover much quicker. This is why the fastest drivers never noticed much of a difference between the two, and the medeocre drivers swear Bridgestones are faster hands down. (For them, they are)
Personally, I think street tires suck , and all you guys are crazy for wanting to autocross GTO's on street tires. If I had one, it would be F-stock or ESP on r-comps. I don't even like autocrossing my own car on street tires, but am forced to at North Hills Sports Car Club events. Even 245 Hoosier A6's aren't enough grip for a 3400lb f-body IMO. Which is why I'm codriving a fully prepared ESP car next year. It just makes more sence to me. Eventually, (when money starts raining from the sky) I'll convert my Camaro to ESP specs. In the meantime, I'll be codriving, or running my car in F-stock (on r-comps). But never Street Touring. Ugh.

[PreludetoaGTO]

None of the street tires exhibit a particularly sudden break away characteristic. What you are thinking of is a characteristic more common to R compounds.

And the Falkens have always been a heavy tire. Their grip does more than make up for it though.

[Rangeball]

Gears, if you go 265 all around I am wondering how much camber you will be able to dial in?

[psu goat]

Thanks for showing up in here Jeff! Obviously if the RE-01R's were available for your size wheel you would have crushed me at those events without a doubt...you've been doing this much longer and are clearly a better driver than myself.

I wasn't trying to sell you short :)

Just like you, when the funding is there, I want to put the blue tank into ESP, but for now STU will have to do.

Personally, I think I'm a little nuts for even autocrossing a 3700 pound car, that wasn't really designed for it due to bushings and tire clearance issues, but it's still a blast and I love the car too much to just sell to have a better autox car.

[Gears for Brains]

This is turning into a great thread - thanks to all who have posted comments. I've just been reading the Tire Rack test results; the most relevant one is here:
http://www.tirerack.com/tires/tests/testDisplay.js p?ttid=100
The Advan was rated highest on the track, while the Direzza and RE-01R got some nice comments about being easy to control at the limit. Too bad the Falkens weren't in this test, that would have been just perfect.

I'm wondering how an 18x9 with a possible offset of 45mm would fit in the back...I would think a little better than an 18x9.5 45et.

Yes, a 1/2" narrower rim will pull in the section width by ~0.2" total (~0.1" per side), according to an old rule of thumb. Most if not all of these tires have their section widths quoted on a 9.5" measuring rim - my numbers are adjusted downward 0.2" for a 9" rim. LBarnes has a thread concerning offset calculations and so on, he might be able to help you with this too.

Gears for Brains, sorry for continuing to post off-topic, but autocross doesn't always get a lot of discussion on this forum, so it might be good to make this an all encompassing auto-x thread. If you want me to move the wheel discussions to another thread, just let me know :)

No problem, I view tires & wheels as a system. Keep on posting and this thread stays near the top. Help spread the gospel of wide front tires! And lightweight wheels! :angel:

However, I don't believe the Bridgestones are much (if any) faster than the Falkens or Yokohamas. But they do recover better. By that I mean if you overdrive a Falken, you have to lift the throttle and slow the car to get it to regain grip. Where the Bridgestone will recover much quicker. This is why the fastest drivers never noticed much of a difference between the two, and the medeocre drivers swear Bridgestones are faster hands down. (For them, they are)

Awesome comment, z28jeff. 100% relevance rating. Thanks for sharing your experience.

Gears, if you go 265 all around I am wondering how much camber you will be able to dial in?

I'm currently at 0.4* & 0.5* negative camber, with at best 1/8" strut clearance. My car is priority #1 civilized daily driver (3 of 4 seasons anyway) then priority #2 autocrosser. I could see running up to maybe 0.8* negative for street use, and with this next go-around of mods, perhaps I'll be able to get there...

[psu goat]

I have -1.1 degrees of camber in the front and could dial in a lot more if I wanted, and I think like -1.8 in the rear. I haven't noticed too much premature tire wear with this much, but then again, I don't plan on the tires lasting more than 10-15k miles anyway.

[Orkboyz]

Understeer or oversteer? The car already understeers pretty badly in those situations. I haven't spent quite enough time autocrossing the GTO to get the tire pressures dialed in. I'm moving back to the prelude this year anyways.


Yeah, oversteer. Sorry about that.

[Gears for Brains]

So far, I'm leaning toward 265/35-18 (best selection of tires, less of a fitment challenge) and the RE-01R (great performance, forgiving). The Dirreza sounds good, but I'd like to hear more user feedback before I try 'em. So far, the cost advantage of the Azenis is not so large as to lure me away from the Bridgestones.

I spoke with my LTW wheels contact, and something he said has gotten me thinking about the fitment side of this project...maybe go ahead with the Noltec offset bushings, to avoid using wheel spacers on the front. Need to run more numbers on that...

[Lithium]

for what it's worth. I ran a set of the azenis 615s for about a year then had to junk them for inspection. I absolutely loved them. I haven't had any other tire like them before, just a pair of Nitto DRs, so I don't have anything to compare to, but they were great.

They performed well above what I expected in the rain. They were as to be expected in the snow. Yeah, I did it a few times in very light snowfall. But on dry pavement OMFG. They a virtually silent, even when pushed very hard. They really only made noise when I took my goat autocrossing with them. I met 2 first time auto-xers who had evos and I had the best time of us 3.

I own one of those G-Tech Pros. If you've never heard of it. You put it in your car and it measures your speeds and Gs forces with gyroscopes I believe. Or some shit, who knows... It works. I have checked it the drag strip and it is very accurate. What I'm getting to it that it measures cornering Gs. LIke a skid pad test.
Using the GTech I was able to get .98 sustained Gs in a old slightly uneven parking lot, in a quick impromptu skidpad test. When auto-xing, at the end of runs I would consistenly have over 1 g in both directions. 1.09 was the best. 1.04g was about average for both directions.

They also had a longer life then expected. I have a pretty heavy right foot too.

The saidewalls are virtually solid. When I dropped the car and tires off to get them put on, a guy at the shop commented on the sidewall stiffness.When I went to get them taken off they had a hell of a time getting them off. It kept popping off the machine and their tool kept popping out. It took two guys and a lot of frustration. I asked him at the end if tires are normally that hard to do. He said it was the tires and he had never seen any tire with sidewalls like that.

Also, I have no suspension mods. When I ran at the scca solo event, there was another GTO. QS w/ Holden badges. He had hotchis sways installed. He was an older guy and said he use to auto cross but hasn't in many years. He ended up being slower than me. He should have had the 615s.

My bro runs them on his Mazdaspeed Protege too.

[psu goat]

Ok, here comes another long post.

From reading your original post again, I looked up the specs for a 255/35/18 dunlop direzza sport z1 off of dunlop's site. The section width on a 9" wide wheel is 10.4" and they recommend an 8.5" to 10" wheel for the 255.

The Rota P45's I want to buy are 18x8" in the front with a 42mm offset. So judging by your first post, with 1" less width in the wheel, should I expect the section width to decrease by 0.4", making it a 10" section width on the 18x8? Also, do you think I would be ok putting a 255 on an 8" wide wheel...seems like there's a decent amount of people running 255, 265, and even 275's on the factory wheels?

So now to try and figure out if the 255's will fit without clerance issues... Right now, I have 245/40/17 RE-01R's on 17x8 40mm offset wheels. The overall diameter is 24.7" and that combined with the offset gives me a ton of room between the tire and strut - I can literally slide my fingers in between the tire and strut, so that's probably about 15mm of clearance.

Tirerack says the 01R has a 9.8" section width on an 8.5" wide wheel, so then by your rule of thumb, on my current 8" wheel, it would be narrower by 0.2", making it a 9.6" section width, right? If all of my math is correct, I would be gaining 0.2" of section width on each side of the tire if I moved up to 255's, so that's 5mm on each side of the tire, which makes perfect sense since a 255 is 10mm more than a 245 :shiner: But would it even be worth it for me to go from 245's to 255's just to get 20 more millimeters of contact patch on the front of the car?

The offset of the new wheel will move it in 2mm closer to the strut, which would make the tires a total of 7mm closer to the strut than where I'm at now. But the Dunlops also have a 25.0" overall diameter, which makes them about 8mm taller overall, so the top of the tire will be about 4mm taller.

With all that calculating then, a 255/35/18 on the wheels I want compared to what I have now should put the tire inward 7mm and up by less than 4mm, so I think they should fit even with 1.1 degrees of negative camber :) If not, I could always put a 2 or 3mm spacer up front just to be safe.

Wow, I don't think I've done that much math in quite some time. haha.

Edit: and here's a really cool tire and wheel offset calculator. LINK (http://www.bigcustomwheels.com/info_specs.jsp)

[Rangeball]

I would say you are probably better off going with the 245's and more camber. Just my $.02.

[psu goat]

Yeah, the more I think about it, and talking with some others on here through PM's, I'll probably just stick with 245's in the front.

[TriflowM5+M3]

+1 Direzza's

[Gears for Brains]

Yeah, the more I think about it, and talking with some others on here through PM's, I'll probably just stick with 245's in the front.

Maybe you've already made your decision, but your calculations in the prior post appear to be on track. It's worth it to spend the time doing the math to figure out what your best setup will be. Yes, 0.2" section width per 0.5" of rim width. The online calculators do NOT take this into consideration. I've made my own wheel & tire spreadsheet to do these calculations including the rim width effect, then it's really easy to play around with different scenarios. I do believe more front tire is needed with this big, heavy car, but I haven't driven a car with serious negative camber, so I may not know what I'm missing!

Are you set on the Rotas? Things may start to break loose with the LTW-5's, keep your eyes open...

+1 Direzza's

Thanks for the input Triflow.

[Gears for Brains]

The LTW-5 thread is up and running now. If you're interested in lightweight wheels, check it out:
http://www.ls1gto.com/forums/showthread.php?t=2211 19

[Gears for Brains]

I've been checking tire vendor sites for new stuff, and I found the Toyo Proxes R1-R. Their blurb talks about autocross-inspired casing design..silica reinforced tread compound...arrowhead tread design (which looks somewhat like the A032R). It has UTQG ratings of 140-AA-A, so it would qualify for STU, as long as they get themselves listed on the SEB. They show a 265/35ZR18, with 275/40R17 "coming soon". Anyone hear anything about this tire? Here's a link:
http://marktg.toyotires.com/file/30251.pdf

[psu goat]

Yeah, I've read a little about the Toyo R-1R and also the Kumho Ecsta XS, but I'm not sure if they'll be available in time to meet the cut-off date for this season of SCCA Solo II.

[Dangerous_Dan]

So this seems like a good tire thread.

What tire pressure should i show up with? I'm use to running a slightly larger sidewall tire on a lighter car. 40ish?

and i was wondering after reading a few of the threads on the strut rub. can you throw some 5 or 10mm spacers on the fronts and bring your camber back towards the negative side?

"I do believe more front tire is needed with this big, heavy car, but I haven't driven a car with serious negative camber, so I may not know what I'm missing!"

I use to run a Crown Victoria and i dialed in -3 deg camber and 1/8" toe out with more 1" offset up front and and 600lb springs to replace the 175lb stockers out back. it rode like crap and wandered at high speed but it turned on a dime.

[psu goat]

A 5mm spacer might be ok, but I'm not sure. I surely wouldn't want to run a 10mm spacer on the front with the stock wheel studs, and I don't think you would even be able to, but I could be wrong. I remember JusticePete saying how big of a spacer you can run on stock wheel studs, so maybe try searching for that.

Gears for Brains, I've been reading more about the Toyo R1R's. You might want to check out the thread on sccaforums about them. From reading on there, it seems like they wear rather quickly, and that was on a honda civic - the big heavy GTO might not like those tires at all, but I guess we won't know until someone tries them.

[SHS]

PSU, Have you picked up a set of the Direzza's? I was going to order some but Tirerack doesn't have 2 of 275's for the rear. I called and the guy told me 8-10 weeks.

[psu goat]

Actually, I think I might just go with the 265's now after you helped me realize that the 265's are as wide as other brand 275's. And Dunlop said that 10.7" section width for the 265 was on an 8.5" wheel. Since the Rotas we got are 9.5", it might make the section width even wider than 10.7".

[TXRaider]

Still pretty happy with my Falken RT-615's. I ran a practice event last weekend where I ran at least 7 or so runs with little cool down down. OK, so finally I started to feel the Azenis heat up get a little greasey.

Dangerous Dan; you asked about pressure, well I'm an admitted noob here, but for rear (275) I don't run near that much. I start at about 34-35ish and they'll heat to 37 quick and usually I'll bleed down to 34 or so. I just don't seem to see the need for that much pressure in the rear (but yeah, I'm a noob!). On front will run 35-37ish but last time I tried bleeding down to 34 on front and I still don't think I was rolling over on the tread. Nice thing about the Falkens, heavy tire but its got a really stiff side wall.

Other guys tire pressue thoughs?

[psu goat]

I can only offer tire pressure advice on the factory 235 Bridgestone Potenza RE040's and 245/40/17 Bridgestone RE-01R's. When I was still running the factory 18's, I had to run around 38-41 psi in the front tires to not get serious tire rollover, but they still rolled. I would usually run around 34 in the back.

With the RE-01R's, I was still running 37-40 psi in the front, with less rollover than the factory tires, and anywhere from 28-35 psi in the rear, depending on rain, temperature, and how much I wanted the back of the car to rotate. I have -1.2 degrees of camber in the front and I think -1.8 in the back due to the sagging factory rear springs. The 01R's would hold heat well, and maybe gain 1 psi of air in between runs.

Hope that helps :)

[TXRaider]

No kidding, only 1 psi of gain with the 01R's? That's pretty good for pushing a 3800lb car through turns. That's really nice for a sticky aggressive tire.

28 in the rear, Ooh never gone that low. Probably could, just never tried that low of a rear pressure.

[psu goat]

Well, with the one club I autocross with, we don't really do back to back runs in one heat. Instead, there's usually 5 or 6 heats - we work the course for one and get one run in every other heat. So with 120 cars, there's time for the tires to cool down by the time I'm getting back in line again.

[SHS]

PSU, if you do a search at google for "dunlop direzza sport z1", a link to a scca forum should pop up (third one down?). They talk about the sport z1 in there. One guy shows a pic of two small 16" tires both sized the same. One is a sport z1 and the other a hancook or something. The Z1 is something like 1"+ bigger than the hancooks. One guy recommends the Z1 for heavy cars because they are hard to get hot on lighter cars. They perform much better when hot, as expected.

[SHS]

This is weird, I just checked the Dunlop site and they took a bunch of size of their website as if they are not available anymore. Tirerack is selling out on those tires quick as well. Hmm!

[Dangerous_Dan]

Well I think ill start out the day with 40 all the way around and make changes from there. My fiance and I are going to be two driving and in my region two driver cars run in the same heat so i imagine ill be dropping pressures pretty regularly throughout the day.

Im really curious to see what kind of alignment this car has, i bought it a couple weeks ago and looking at the service report its had a strut replaced so there is no telling what they did to make sure it wouldnt happen again.

[Gears for Brains]

Hey, good to see this thread getting some more activity.


I use to run a Crown Victoria and i dialed in -3 deg camber and 1/8" toe out with more 1" offset up front and and 600lb springs to replace the 175lb stockers out back. it rode like crap and wandered at high speed but it turned on a dime.

Wild setup. I'm going to be doing some more experimenting this year...must tweak setup for more camber...

A 5mm spacer might be ok, but I'm not sure. I surely wouldn't want to run a 10mm spacer on the front with the stock wheel studs, and I don't think you would even be able to, but I could be wrong. I remember JusticePete saying how big of a spacer you can run on stock wheel studs, so maybe try searching for that.

Gears for Brains, I've been reading more about the Toyo R1R's. You might want to check out the thread on sccaforums about them. From reading on there, it seems like they wear rather quickly, and that was on a honda civic - the big heavy GTO might not like those tires at all, but I guess we won't know until someone tries them.

I think Pete has said you're OK up to a 6mm spacer, but check your thread engagement! Good use for the stock open lugnuts.

Thanks for the pointer to sccaforums.

~~~~~~~~~~~~~~~~~~~~~~~

I've gotten side-tracked from tire selection due to the chronically difficult GTO wheel fitment dilemma...been trying to get people on board for some lightweight LTW wheels dialed in for the GTO, this is an update of the original link posted earlier:
http://www.ls1gto.com/forums/showthread.php?t=2245 80

With my OE 17's, I ran the fronts as high as the rated max 51 psi to avoid rollover...POS KDWS's. With my GS-D3's, I think I was running mid-40's in front and low-30's in the rear (staggered, see sig). I'm still an autocross novice, so take this FWIW.

[St.Mary]

The biggest problem with these cars stock is camber (or lack of). You can pump up the tires all you want but you will still see "roll over" simply because any tipping of the car will put the tire on its sidewall. The 615's seemed to help alot...then again they do have a tread that rides up the sidewall a bit.

Pedders, please make adjustable camber top bushings for us autocrossers :thumbs:

I'd love to have -1 on the street and a quick adjustment to -3 for autocross!

[TriflowM5+M3]

Quite a few BMW M5 buddies of mine are currently running the Direzzas and love them. They have great wear, especially for a 4000+lb super sedan and have grip and communication thats on par or slightly ahead of the RE01's for less cash. I would honestly put them on my rig if i was going to keep the car.

[SHS]

Ordered my Direzza's yesterday. Woot!

[Gears for Brains]

I'm still going back and forth between a couple potential setups, and for the sizes I'm thinking about the RT-615, Dirreza Sports, and RE01-R are all in contention. Can anyone comment on the relative "squareness" or "rounded-ness" of the shoulders on these tires? My current Goodyears are quite square in the back (275/40-17) but quite rounded in the front (255/40-17), surprisingly different for the same tire model. I think the fronts were made in W. Germany while the rears were made in the USA...

Here's my immediate plan: order 7/32", 5/16", and 7/16" generic spacers from Jeg's ($39 investment). Get out the fender roller and see what I can do with the front fenders. Incrementally space the front wheels out until I encounter rubbing. Then make an informed decision about the maximum feasible tire. The only drawback is my current front tires are shorter than some of the tires I'm looking at. My stock wheels would require too much spacer to use for this.

I also plan to slot the struts a little more, but that will only give me another 1-2mm.

The biggest problem with these cars stock is camber (or lack of). You can pump up the tires all you want but you will still see "roll over" simply because any tipping of the car will put the tire on its sidewall. The 615's seemed to help alot...then again they do have a tread that rides up the sidewall a bit.

Pedders, please make adjustable camber top bushings for us autocrossers :thumbs:

I'd love to have -1 on the street and a quick adjustment to -3 for autocross!

Thanks for the feedback, I'm definitely going for more camber with this round of mods. I'll use some good Skulte spacers as needed in the final package. Any suggestion for the max streetable camber angle? I don't want to be tweaking the alignment before & after each event - at least until a nice camber-adjustable top mount system comes along. Gravana/B+G claims to be working on one...

Quite a few BMW M5 buddies of mine are currently running the Direzzas and love them. They have great wear, especially for a 4000+lb super sedan and have grip and communication thats on par or slightly ahead of the RE01's for less cash. I would honestly put them on my rig if i was going to keep the car.

Very good feedback on the Direzzas, if I decide on 265 or 275/35-18 I may go with them.

[SHS]

I would go with the 265 Direzza's since that tire is 10.7" wide. That width is the same for the 275 Goodyear's. The tread is square, in fact, on Dunlops website they don't even list a tread width like the RE01R's list for example.

The tire carcass is stiff! I can sit my 200 lbs on the unmounted tire and there is NO squashing.

[psu goat]

Yeah, I went with the 265 direzzas too and can vouch for the stiff sidewall...I did the same test with my 180 pound self.

The 245 direzzas in the front seem pretty wide too, but I don't have my 01R's anymore to compare them side by side. I'm thinking I might need a 2 or 3mm spacer in the front to get them to fit with the Rotas (42mm offset) and -1.2 camber.

[FastEddy]

Any suggestion for the max streetable camber angle?

I asked that question recently and got some conflicting info here: http://ls1gto.com/forums/showthread.php?t=212485&highlight=max+camber

I am leaning towards running about -1 full time. I also have played with my digital camber gauge and have determined that 5mm at the rim = 1.2 degrees of camber; 2.5mm = .6 degrees of camber ; 1.25 mm = .3 degrees of camber. That may help when you get down to the wire.

I still would like an answer as to how close you can be to the strut. Pedders says a pencil, but I know you can get away with much less than that.

The Re-01r's seem to be fairly rounded. If you have a way for me to measure them for you with any accuracy let me know. They are sitting in my garage. You should also consider that the tire width compared to the rim width will have an affect on that as well. The wider you get from the recommended size the more crown you will get.

I was really getting spring fever last week and getting fired up to get mine on, then it snowed again yesterday and last night.:banghead:

Pat

[psu goat]

Grrr, just after buying and mounting up the Dunlop Direzza Sport Z1's, sccaforums is now saying that the Z1 has been discontinued. Dunlop is instead going to start bringing over the "Z1 Star" with a new compound, but same tread design.

Tirerack is now having a firesale on all remaining sizes. I paid $227 each for the 265/35/18's...there's 2 left now for $193 each and they now have a $50 rebate when you buy 4 Z1's. I'm gonna call up Rudy tomorrow (salesperson I dealt with) and see if I'm still eligible for the $50 rebate since I bought mine after March 1st.

SHS...did you buy your Z1's from tirerack too?

[Scooter70]

Here's my immediate plan: order 7/32", 5/16", and 7/16" generic spacers from Jeg's ($39 investment). Get out the fender roller and see what I can do with the front fenders. Incrementally space the front wheels out until I encounter rubbing. Then make an informed decision about the maximum feasible tire. The only drawback is my current front tires are shorter than some of the tires I'm looking at. My stock wheels would require too much spacer to use for this.

I also plan to slot the struts a little more, but that will only give me another 1-2mm.



Thanks for the feedback, I'm definitely going for more camber with this round of mods. I'll use some good Skulte spacers as needed in the final package.

Sounds like a solid plan. I think I've heard it somewhere. ;) I should be there next week.

[St.Mary]

Grrr, just after buying and mounting up the Dunlop Direzza Sport Z1's, sccaforums is now saying that the Z1 has been discontinued. Dunlop is instead going to start bringing over the "Z1 Star" with a new compound, but same tread design.

Tirerack is now having a firesale on all remaining sizes. I paid $227 each for the 265/35/18's...there's 2 left now for $193 each and they now have a $50 rebate when you buy 4 Z1's. I'm gonna call up Rudy tomorrow (salesperson I dealt with) and see if I'm still eligible for the $50 rebate since I bought mine after March 1st.

SHS...did you buy your Z1's from tirerack too?

Damn, I was wondering why those were so cheap and sizes started disappearing. Did they say if this "star" compound is that much better? What will prices look like?

[psu goat]

The "Star" compound ones get up to operating temperatures more quickly and provide better turn-in response, from what I read on sccaforums. One poster also said that the sidewall is softer than the RE-O1R, which may not be a good thing since our cars like to understeer a bunch. Plus, if they heat up more quickly, they might not be the best thing to have for a big heavy car like the GTO either...guess we won't know until someone tries out both versions of the Z1.

[SHS]

Hey PSU,

I did order from tirerack. Two days after I bought the tires, I noticed the price had dropped. So, I emailed customer service and asked if I could get the new price for the 265's. They gave me the new price for one of the tires. I do have the rebate form and I thought about calling again to see if someone would sign it for me. We'll see.

I have been watching that same SCCA forum (when I first found that it only had a page of posts, then I went back 3-4 days later and it had exploded to like 5!) thread. I think that the harder compound would be better for us GTO drivers. I speculate that Dunlop noticed all the STI, EVO, Neons, Miata, etc where buying the tires and then complaining that the tire took to long to heat up. The fat ass GTO shouldn't have a problem with that.

I can't wait to get mine on and bomb some off-ramps.

[r0nd3L]

One question, you guys think it's possible to run 265 tire on 8.5" wheel? I mean is it safe and good performance wise. It seems like most companies (Bridgetstone/Falken/Dunlop) recommend minimum 9" width for 265.

I really want to run 265 all around on 18x8.5" ET40 front and 18x9.5" rear wheels along with Ground Control coilovers and Noltec/Lovells camber adjustable strut mounts.

Or is it kind of stupid to run same width on staggered wheels?

[SHS]

I don't think running a 265 Direzza Sport Z1 would be a wise choice. This tire has some STIFF sidewalls. Like I said before, I weigh 200 lbs and sat on the unmounted Direzza and it didn't move. I think that there would be a safety issue with these tires.

If you were going to use street tires that had softer sidewalls, those would probably be okay considering what other guys have done on here. I am speaking out of vicarious situations not personal experience.

Another issue is that you will need spacers and very little camber in the front to fit a 265, but maybe you already considered that.

Good luck!

[r0nd3L]

I don't think running a 265 Direzza Sport Z1 would be a wise choice. This tire has some STIFF sidewalls. Like I said before, I weigh 200 lbs and sat on the unmounted Direzza and it didn't move. I think that there would be a safety issue with these tires.

If you were going to use street tires that had softer sidewalls, those would probably be okay considering what other guys have done on here. I am speaking out of vicarious situations not personal experience.

Another issue is that you will need spacers and very little camber in the front to fit a 265, but maybe you already considered that.

Good luck!

Thanks for the input. It would be kind of nice to find 9" wide wheel that's around 40mm offset and run it all around with 265s.

As far as the fitment and rubbing issues up front, wouldn't the camber adjustable strut mounts allow for more space? I would use OEM adjustment set towards more positive camber and the adjustable strut mount to get me some negative camber. In theory, that should give me more space for tire right?

Unless I'm completely off here :banghead:

[Gears for Brains]

I asked that question recently and got some conflicting info here: http://ls1gto.com/forums/showthread.php?t=212485&highlight=max+camber

I am leaning towards running about -1 full time. I also have played with my digital camber gauge and have determined that 5mm at the rim = 1.2 degrees of camber; 2.5mm = .6 degrees of camber ; 1.25 mm = .3 degrees of camber. That may help when you get down to the wire.

I still would like an answer as to how close you can be to the strut. Pedders says a pencil, but I know you can get away with much less than that.

The Re-01r's seem to be fairly rounded. If you have a way for me to measure them for you with any accuracy let me know. They are sitting in my garage. You should also consider that the tire width compared to the rim width will have an affect on that as well. The wider you get from the recommended size the more crown you will get.

I was really getting spring fever last week and getting fired up to get mine on, then it snowed again yesterday and last night.:banghead:

Pat

Thanks again, Pat. Very interesting read. I could see the fluid-filled radius rod bushing allowing all kinds of toe change resulting in tire wear. With my upgraded front suspension, I'm going to try for 0.8/1.0* negative.

Sounds like a solid plan. I think I've heard it somewhere. ;) I should be there next week.

Busted! Yeah, not my original idea...thanks Matt.

One question, you guys think it's possible to run 265 tire on 8.5" wheel? I mean is it safe and good performance wise. It seems like most companies (Bridgetstone/Falken/Dunlop) recommend minimum 9" width for 265.

I really want to run 265 all around on 18x8.5" ET40 front and 18x9.5" rear wheels along with Ground Control coilovers and Noltec/Lovells camber adjustable strut mounts.

Or is it kind of stupid to run same width on staggered wheels?

LBarnes is running 265's on 18x8.5 per a recent thread. Why not run 275 rear tires since the wheels will be different anyway?

Thanks for the input. It would be kind of nice to find 9" wide wheel that's around 40mm offset and run it all around with 265s.

As far as the fitment and rubbing issues up front, wouldn't the camber adjustable strut mounts allow for more space? I would use OEM adjustment set towards more positive camber and the adjustable strut mount to get me some negative camber. In theory, that should give me more space for tire right?

Unless I'm completely off here :banghead:

18x9 +40 wheels are out there, but could be trouble with the rear fenders. ASA AR-1 18x9 +45 is fairly light and quite affordable...if you could deal with spacers in the front.

Offset strut bushings will give you 5-6mm more room to the inside. Slotted strut bracket holes could give you another 1-3mm depending on how daring you are.

[Scooter70]

Busted! Yeah, not my original idea...thanks Matt.


Hopefully we both come to the same (or or at least similar) conclusion. However, I'm going to see if I can go crazy with camber for the track and then tip them back up for the street.

[TriflowM5+M3]

Just saw the TR add for it...only 50 bucks back but i guess that pays for the shipping to my place in Vegas.

I might just have to jump on these and as others have expressed, im not 100% convinced that the "upgrade" compound will be better for the GTO.