The Official WHEEL FITMENT Thread

[bwh13]

According to the wheel offset calculator I use, if I use a 8" wheel with the +18 offset (which is described as the optimum), the outer part of the wheel will move to the outside 40mm, that seems like it would be too far. 28-33mm seems to be the best as it moves the outer wheel 25-30mm.

[White Nightmare]

I've got a question. I have heard some people say that +20 is the best offset for a 16x8 on a e30 but then I have also heard people say that a +25 offset is best. I would like to run a tire size that is either straight up and down with the width of the wheel or a tiny bit of stretch. Id also rather not roll my fenders if possible. Thanks guys.

-Chris

[Borat]

ET25 is ideal for 7.5, however that is close to the strut. If you have the smaller 45mm struts you might get away with ET25 on 8" rim. Otherwise just go for ET20 and run the risk of rolling guards.

[Mystikal]

As the resident E30 wheel fitment expert (or complete internet resource), I can't agree with this thread.

There are many other factors which matter, the most significant being wheel diameter and tire variance. For example I can mount 17x7 ET40 wheels all day without spacers, but for 15x7 ET27 or so is the minimum. Tires sizes and shapes also vary quite a bit.

I have an extensive wheel fitment thread on my other forum, maXbimmer. People ask questions very frequently, I like to treat them on a case by case basis. Here is the thread: http://www.maxbimmer.com/forums/showthread.php?t=54146. 371 posts and 18,244 views at the moment. As you can see when you read through, it's more than simple numbers.

Rough estimates in this thread are just that, rough. When you're ready to know if it will work, ask over there.

[White Nightmare]

ET25 is ideal for 7.5, however that is close to the strut. If you have the smaller 45mm struts you might get away with ET25 on 8" rim. Otherwise just go for ET20 and run the risk of rolling guards.

Thanx for the info man :up:


-Chris

[BigD]

As the resident E30 wheel fitment expert (or complete internet resource), I can't agree with this thread.

There are many other factors which matter, the most significant being wheel diameter and tire variance. For example I can mount 17x7 ET40 wheels all day without spacers, but for 15x7 ET27 or so is the minimum. Tires sizes and shapes also vary quite a bit.

I have an extensive wheel fitment thread on my other forum, maXbimmer. People ask questions very frequently, I like to treat them on a case by case basis. Here is the thread: http://www.maxbimmer.com/forums/showthread.php?t=54146. 371 posts and 18,244 views at the moment. As you can see when you read through, it's more than simple numbers.

Rough estimates in this thread are just that, rough. When you're ready to know if it will work, ask over there.

And to add more to what Jay said, I just got a set of 17x7.5" wheels ET45. Guess what, they FIT in the rear, that's right, they FIT. In the front, they almost fit, the tire rubs the strut. I can put them on flush with the hub but they don't turn because the tire is jammed into the strut. With some 15mm spacers at ET30, by my calculations I will be right on the money.

[FrustratedMunky]

How about 15x7 ET13? What's the fattest I can go without fender work?

[Mystikal]

And to add more to what Jay said, I just got a set of 17x7.5" wheels ET45. Guess what, they FIT in the rear, that's right, they FIT. In the front, they almost fit, the tire rubs the strut. I can put them on flush with the hub but they don't turn because the tire is jammed into the strut. With some 15mm spacers at ET30, by my calculations I will be right on the money.

So those Koseis ended up being ET45? Even better, 15mm hubcentric will be perfect. It's the wheels that have VW-like offsets (in the 30's) that can be a headache, because getting proper hubcentric spacers that won't cram wide tires into fenders is impossible.

[Mystikal]

How about 15x7 ET13? What's the fattest I can go without fender work?

205s, even then with 205/55's you'll probably need to roll in the rear.

[FrustratedMunky]

Is it possible to run 225/50/15 with rolling? I guess it'll either have to be 205/55 or 225/50 (if that's even possible)

You're running 225/50/15 on ET20 aren't you? Will the extra 7mm destroy the fenders?



It looks like it would be pretty damn close...

Nice pic btw

[iwantone]

umm.... i dont agree with your numbers at all.
im new to the e30, so i might not know what would be flush and what isnt.
but it seems as though your numbers are way off.

you list that for a 7" rim, a et of +5 would be flush.
BUT, then you say a 9" rim with -5 offset would be flush also.

do you have a different meaning for flush for different widths?
because according to http://www.1010tires.com/WheelOffsetCalculator.asp
a 9" rim with -5off, will stick out 34mm farther than a 7"rim with +5off.

PLEASE clarify, because the wider the wheel is, the higher offset you must
run to achieve the same "flushness" as a more narrow wheel.

im sure a 9" wheel with -5off, will fit. but there has to be much more fender
work/it must sit lower/have more camber/etc. than with a 7" and +5off.

[Hick]

muhuhaha! ive got 16X7 Et26 fittipaldi 5 spokes with 215/50 eagle f1 gsd3. In other words, PERFECT!!

[Mystikal]

Is it possible to run 225/50/15 with rolling? I guess it'll either have to be 205/55 or 225/50 (if that's even possible)

You're running 225/50/15 on ET20 aren't you? Will the extra 7mm destroy the fenders?

It looks like it would be pretty damn close...

Nice pic btw

Not a chance on the 225's. The only reason I can get away with my setup (unrolled fenders to boot) is because I have stiff springs (GC 475 lb/in linear) and the ZE-512's run very narrow. The section width of a 225/50/15 ZE-512 on my rim is only 8.9", compared with other 225's such as the G-Force Sports at 9.2". In fact, my tires were basically the same width as 215/50/15 G-Force Sports; essentially always think of ZE-512's as one size narrower.

So, once you consider that I'm really running 215's, the extra 7mm is definitely a cause for concern. I couldn't run anything wider on my wheels without some work, no question about it.

And thanks for the compliment, I particularly love that pic too. :)

[Jean]

Mystikal, thanks for the link i'll have to read through all 25+ pages later on. I have a couple specific questions for you that maybe you'll be able to answer.

I am looking for a 15-16" wheel about 7-8" in width that will fit right w/o spacers or adapters. Car is on 500front/650rear spring rates and if needed I will roll the front and/or rear outside lips as needed. I am more concerned with picking the right width/offset to make sure they don't hit the front struts on the inside and don't limit me too much to only 205width tires.

Would a rota slip 15x8 in et20 be a direct fit and won't rub on the inside front strut with 225 50 15 r-s2 or t1r tires ?

Would a rota slip 16x8 in et20 also be a direct fit with 225 50 16 or would i need to run 225 45 ?

Thank you.

[Mystikal]

Hey Jean, it's quickly starting to look like this thread will turn into a clone of the one on maX. That's okay with me, I'm happy to share the info as true knowledge on this topic is extremely rare (most people go from heresay, answers become incredibly vague).

With 15x8 ET20 wheels and 225 tires, there is a slight chance you will need tiny spacers to clear the front struts. Like 3mm. This is totally dependent on the size of the curb protector in the tire, if there is any.

With 16x8 ET20 wheels and 225 tires, you will not need any spacing. This is due to the inclination of the struts, there is more room for larger wheels on the inside. You can get away with 225/50/16 if you have semi-extensive fender work (a member here who recently changed his username from Mtriple had that size R-comp on his white track car).

With either Rota wheel, fender rolling will be required all around.