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Discussion Starter #1
Looking at buying a set of Beyern Rapp's 19x8.5 40mm all around super cheap. Will they fit the rear on a stock suspension car? If so, any ideas on tire size? I know the ideal offset is 45-50mm, but most are running a 9.5" wide wheel. Figured with these being 1" narrower it might forgive some of the offset difference. Maybe I'm an idiot, idk. Thanks!
 

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Compared to stock you will have 3mm more clearance to the shock and 3mm closer to the fender.
 

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Well, ok, let’s see;
8.5” wheel is 0.5” wider compared to OEM. So you have extra 12.7 mm that has to go somewhere.
If offset was the same as OEM wheels (+48), your new wheels would take extra 6.35 mm in each direction.
Now, because offset on new wheels is +40, that means new wheels would move outward by 8 mm.
So, final numbers for the new wheel would be +14.35 mm outwards and -1.65 mm inwards.
Disclaimer; I am not wheel fitment expert, just doing the math to the best of my knowledge.

Will it rub? Who knows? Depending on tire width and height, car height, camber, subframe alignment, springs stiffness, if fenders are rolled and by how much...there are so many variables even with stock suspension.

In general, it is better to go with more offset. That way you can always use spacers and fine tune it. You can always move the wheels outwards with spacers, you can never move it inwards.

Now, here it comes; my guess is you will rub on fenders if everything is stock.
8.5” wheel with 45 mm offset may be the most workable solution to fit front and back without having to roll fenders and use any spacers???
 

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Unless you are ready to do coilovers and fender rolling/cutting, maybe better look for something that is known to fit.
Otherwise, if you are planing on coilovers and other mods, maybe better to look for wider wheel to start with.
I have Apex EC-7 18 x 9 +42 and they'll be for sale soon. Getting 18 x 10. It's always like this, never enough. Better plan far in advance and do it once.
 

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Wol Gemut
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on the front, it is very nearly ideal, so with a 245 tire, which is a good fit on 8.5 wheel, nearly perfect. On the rear, also with a 245 tire, you should be fine as well. here is why: say that it was a 275 tire on the very good offset of +50. that 275 tire has to have 15mm more on each side than the 245 tire does. but you are only giving up 10mm from +50 to +40. it is very similar to running 265s on a +50 offset, which is not generally an issue. do not be thrown off by the fact they are 8.5s. that is NOT added to the tire width. first of all, it means only 6mm on each side, and the inside is irrelevant with that offset. secondly, the only difference it makes is the very slight amount a wider wheel might stretch the 245 tire. This would be 1 or 2 mm at the most. that is, the 245 tire will obviously be the same width, whether on 8" or 8.5" but 8" might pull in the bulge ever so slightly more.

edit: you will want to be sure they are 5x120. since they are Beyern and they make BMW wheels, also 5x120, I am guessing you have that covered.
 

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Well, ok, let’s see;
8.5” wheel is 0.5” wider compared to OEM. So you have extra 12.7 mm that has to go somewhere.
If offset was the same as OEM wheels (+48), your new wheels would take extra 6.35 mm in each direction.
Now, because offset on new wheels is +40, that means new wheels would move outward by 8 mm.
So, final numbers for the new wheel would be +14.35 mm outwards and -1.65 mm inwards.
Disclaimer; I am not wheel fitment expert, just doing the math to the best of my knowledge.

Will it rub? Who knows? Depending on tire width and height, car height, camber, subframe alignment, springs stiffness, if fenders are rolled and by how much...there are so many variables even with stock suspension.

In general, it is better to go with more offset. That way you can always use spacers and fine tune it. You can always move the wheels outwards with spacers, you can never move it inwards.

Now, here it comes; my guess is you will rub on fenders if everything is stock.
8.5” wheel with 45 mm offset may be the most workable solution to fit front and back without having to roll fenders and use any spacers???
Great write-up! However, you can move wheels inward with offset hubs, but it's best to avoid that with proper offset and proper suspension.

I rubbed in the rear with 265/35/18 wrapped around 18x9 +45. I have was told I have some major rear spring sag, I cut my fender lips down to about 0.5" and this spring will be coilovers and poly bushings. Take it from me, I bought new wheels and tires, and then it was cutting and hard launch trial and error until I stopped seeing my rubber being shredded. Get some coilovers or upgraded springs before you ruin your tire investment.
 

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Discussion Starter #11
on the front, it is very nearly ideal, so with a 245 tire, which is a good fit on 8.5 wheel, nearly perfect. On the rear, also with a 245 tire, you should be fine as well. here is why: say that it was a 275 tire on the very good offset of +50. that 275 tire has to have 15mm more on each side than the 245 tire does. but you are only giving up 10mm from +50 to +40. it is very similar to running 265s on a +50 offset, which is not generally an issue. do not be thrown off by the fact they are 8.5s. that is NOT added to the tire width. first of all, it means only 6mm on each side, and the inside is irrelevant with that offset. secondly, the only difference it makes is the very slight amount a wider wheel might stretch the 245 tire. This would be 1 or 2 mm at the most. that is, the 245 tire will obviously be the same width, whether on 8" or 8.5" but 8" might pull in the bulge ever so slightly more.

edit: you will want to be sure they are 5x120. since they are Beyern and they make BMW wheels, also 5x120, I am guessing you have that covered.
So would I be able to run a 255 rear or would I need to stick with the 245? I don't mind rolling my rear fenders. The car has fairly new paint and I have 2 or 3 friends with Eastwood rollers
 

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Wol Gemut
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So would I be able to run a 255 rear or would I need to stick with the 245? I don't mind rolling my rear fenders. The car has fairly new paint and I have 2 or 3 friends with Eastwood rollers
with 255s the 10mm you are giving from +50 to +40 makes it like running 275s with the +50. this can certainly be done, but it will require rolling fenders to spot welds (I would not roll past that, the bend provides stability),
500415
and probably some stiffer springs or coilovers. so, with 245s, I see it very likely safe with just rolling. 255s would probably require the coilovers, which change the ride quite a bit. also, 255s in the front would not be a good natural fit, no matter the offset. btw, I run 285s on 19x10.5s in the rear, + 52, and 19x8.5s on 245s at +42 in the front. rolled to spot welds (rears only), and Pedders coilover shocks and -20 lowered springs in the rear. I never rub with this setup, in fact, I am closer on the inside to danger than on the outside, and you will have no concerns on the inside.
 

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Great write-up! However, you can move wheels inward with offset hubs, but it's best to avoid that with proper offset and proper
Yes, but only rears, at $750 for offset stubs, having to mount brake calipers with spacers which screws up any future big brake kit upgrades, takes away clearance if coilovers with external canisters are used, and it’s lots of work to install those stubs. I looked into this just last week and it didn’t seem that attractive. Money would be better spent on correct wheels IMO. Or wheels with extra positive offset, spacers and arp studs.
 

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On all this different tire width talk, I’d say it’s hard to know. Actual tire width doesn’t correspond to numbers printed on tires. Some tires are wider than others for the same number.
If you are keeping the same tires, get some cheap 3/8” or 1/2” wheel spacers at pep boys or eBay and put them in with you existing wheels just for the test. If it’s not rubbing you are good to go.
 

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So would I be able to run a 255 rear or would I need to stick with the 245? I don't mind rolling my rear fenders. The car has fairly new paint and I have 2 or 3 friends with Eastwood rollers
Be ready for cracked paint when rolling fenders.
Front fenders are really easy to roll on these cars but plastic inner fender hast to come out and be cut as it probably won’t fit inside the fender lip any more.
Rear fenders are real pain to roll. There is spot welding that makes it difficult and tires usually rub at the rear part where fender meets bumper. There is not much you can gain in that spot.
One more thing; check your tire to fender lip clearance on left vs right side. Like even just sticking your thumb in there would give you rough idea. If one side has more clearance than other side, it is tighter side that you have to make sure it’s clearing. To make it even it may require sub frame realignment and/or pulling fenders.
 

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Yes, but only rears, at $750 for offset stubs, having to mount brake calipers with spacers which screws up any future big brake kit upgrades, takes away clearance if coilovers with external canisters are used, and it’s lots of work to install those stubs. I looked into this just last week and it didn’t seem that attractive. Money would be better spent on correct wheels IMO. Or wheels with extra positive offset, spacers and arp studs.
Exactly, money much better spent elsewhere.
 

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Be ready for cracked paint when rolling fenders.
Front fenders are really easy to roll on these cars but plastic inner fender hast to come out and be cut as it probably won’t fit inside the fender lip any more.
Rear fenders are real pain to roll. There is spot welding that makes it difficult and tires usually rub at the rear part where fender meets bumper. There is not much you can gain in that spot.
One more thing; check your tire to fender lip clearance on left vs right side. Like even just sticking your thumb in there would give you rough idea. If one side has more clearance than other side, it is tighter side that you have to make sure it’s clearing. To make it even it may require sub frame realignment and/or pulling fenders.
+1 to avoid rolling the rear, due to paint cracking either right away or eventually.

I rubbed really close to where the fender met the bumper. Took out the splash guard, cut right up to the bumper, and then cut the splash guard to match. It was a pain with the trial and error cutting. Save time and sanity and look into suspension.
 

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tire widths do not vary much from brand to brand. the section width is required to match listed specs, what does vary a small bit is tread width. anyway, the section width and tread width are listed with the specs of every tire made. easy to check. I have a set of 285 Michelin ps4s and 285 Yokohoma Advan Sport v105 on two sets of same wheels, and they fit the same too, possible 0,1,2 mm different, difficult to tell they are so close, no impact of fitment for sure. one can see how ideal these Bayern wheels are for fitment in that if one decided to widen them one inch for the rears at some future point, making them 9.5s, the offset would be between +52 and +53, very nearly if not ideal for 275s. (widening affects fitment only on the inside, outside remains the same). the question was for fitment advice, and they do. but they are also a great looking wheel, and if not hot, and if they are silver, my opinion is they would be a great purchase at that price and a great looking wheel as well. of course, it goes without saying, each person decides for themselves what they see as worth the price in their budget.
 
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