Wheel/Tire question?

[bigjim]

I know this sounds funny but I just found out that the bolt pattern on our cars is a 5-120mm. I know this sounds funny, but I have never had a reason to know. I am in the market for rims real soon and had a couple of questions to run by everybody. Since I can't get the ROH drift R's anymore I was wondering about the TSW Thruxtons? I know a 9.5" wheel will fit on the back, I had some questions about the last HB number? one says 45HB and the other says 20HB what is the difference in the two and what does the HB number stand for? Sorry for all of the newb questions, but I have just never heard of that HB number.
Rear Wheels
18X9.5 5-120 45HB
18X9.5 5-120 20HB
Front Wheels
18X8 5-120 40HB
Also, When buying tires I know I am going to need a 245/40/18 on the front, but I coudn't rember what people are using on their rear wheels. I don't know if I should put a 275/40/18 or a 275/35/18. I do like the look of a thicker sidewall, but if the 35 sidewall width is the only option that will be allright. The last thing I was wondering about is with these wheels exactly how much will the rub with 275's? I figure when I get wheels I either am going to have to cut my fenders or get them rolled? Sorry for the lengthy post, but if I am going to get wheels I want to do it right.

[sccaGTO]

Ok, Jim, let's sort this out one at a time. The HB number is another way of designating the wheel's offset. For the rears, you will definately need the 45HB. A 20HB wheel will stick out of the fender like a monster truck. The 275/35/18 is what you must use for the rear. A 275/40/18 is what C5 'Vettes used. This will rub big time. You will need to roll/grind your rear fender lips in order for them to work, no matter what brand. If you go with a 265/35/18, you might not rub. But, I would search the forum for people running that size tire on that particular size & offset of wheel before stepping down a size.

[bigjim]

Ok, Jim, let's sort this out one at a time. The HB number is another way of designating the wheel's offset. For the rears, you will definately need the 45HB. A 20HB wheel will stick out of the fender like a monster truck. The 275/35/18 is what you must use for the rear. A 275/40/18 is what C5 'Vettes used. This will rub big time. You will need to roll/grind your rear fender lips in order for them to work, no matter what brand. If you go with a 265/35/18, you might not rub. But, I would search the forum for people running that size tire on that particular size & offset of wheel before stepping down a size.

Thanks for all of your help. I am will get the 275/35/18 then. I know there are people running that combo, so I think I willl have no problems running the 275 tire size. I will have drag bagd so I won't have to worry about grinding the fenders or rolling them immediatly, but eventually I will get them rolled.