fivestar

What is the widest tire I can install on factory IROC 15" Rims? I have an 89 Iroc and that did not have the original rims. I found some original 15" rims for O$ and want to install, wondering if I can install 245/50/15 tires or perhaps 245/55or60/15's on the factory 15" rims...Thanks for your help

Fivestar

Ron U.S.M.C.

I don't know how wide your wheels are but here’s what I'm running
235/60r15s on 7in. wide wheels front and 255/60r15s on 8in.wide wheels rear.
Anything larger than that on my 5.0 streetcar just looked out of place.

luvofjah

iTrader: (2)

Nice Ron...
I have 245's on my 15x7, no problems ...

Rafael

devestator_x

iTrader: (1)

Ron, that is a great look. I was actually looking that these exact rims earlier tonight on tirerack. Are those the 8" with -19mm offset in the rear and 7" with -6mm offset in front? If so, that's the perfect sales pitch for me to show the wife and say "Look, this is how much will stick out in the rear."

Ron U.S.M.C.

That 15in. wheel only comes in a 3.75 BS. (3- 3/4 )That puts the wheel out a little further than most want because of the larger wider tires not tucking in under the well. BUT.....I have found that running 255/60r15s in the rear is perfect. The tread is just inside the well and the bulge of the tire is flush with the fender flair. Don't forget that I run a old school staggered set of wheels. That means that there are 15x7in. wide wheels front with a nice dish but the 15x8in. rear wheels have a larger dish as you can see in the photo. That allows me to use the thinner/smaller tire in the front and the larger tire in the rear.
Heres a link showing the wheels and tires = https://www.thirdgen.org/forums/whee...er-cobras.html

The offset you mentioned is correct.

This is what they look like when you open the box.
I recommend a set of locking lug nuts.


They are a clear coated aluminum wheel that you only use soap and water on when you clean them.Ive had mine for over 6 years and they still look new.

devestator_x

iTrader: (1)

That stagger is what I was looking for the most and yours looks perfect. I had been toying with the idea of C7 Vette rims and spacer and all that crap, but after seeing yours, Im sold. The 15" size allows me to reuse my current tires as well. They are still a few years away from needing replacement, and ironically, I also have Cooper Cobras, but Im at 235 all around as they are on the stock Z28 rims. Thanks for the link to the other thread, wife really likes the look of them.

Ron U.S.M.C.

Glad I could help.
Those wheels are a rare breed around here.The only other set I know of are on a friend of mines car. He has the Baddest black Camaro I've ever seen and those wheels look great on it . Welcome to the pack.
Please take photos as you go and post the best ones on this thread.

Skinny Neb

iTrader: (2)

There are some people around here that have told me you can run up to a 265. I personally ran 255's on the back of my S10 on Z28 wheels, and they worked out fine.

Ron U.S.M.C.

I just tried to find a tire in that 265 size and could not find anything.

I also can’t find anything other than a Hoosier drag tire in245/50r15 and nothing in a 245/55r15. So a 245/60r15 will be fine on a 7in. or8in. wide wheel. When it comes to 15in. wheels I prefer a staggered look as opposed to having the same size tires front and back. The photos above have a staggered set.

We have many guys here running 275/60r15 , 28in tall drag radials on 8in wide wheels primarily for 1/4 mile racing but if you're not racing than IMO it’s too much tire. Heck Tire Rack even says you can run a 295/50r15 on an 8in. wide wheel. IMO that's also too much tire for that size wheel and looks out of place on anything other than a track car.

Also when guys say factory wheels or just Z28 wheels other than the actual size (7x15 or 8x15) that does not help someone find you tires. Please specify wheel size when you ask about tires.
Side note = To answer your question IMO a 235/60r15 on a 7in. wide wheel in front and a 255/60 r15 on a 8in. wide wheel looks best, just like in the photos above.

fivestar

Thanks Ron,
To be honest I did not know that 15" Iroc Z rims came in 7" or 8" widths ssooo I went outside and crawled under my Iroc and found they are the 8" width. So it seems I can run nearly the same width tire on the 15" as I do on the 16inch rims (from my 88 Iroc vert) that I have.
One my rear 88 Iroc 16" rims got damaged and finding one good one locally has been tough. I happen to have a full set of 89 Iroc 15" rims and simply did not know what would fit... I appreciate your replies and thank you for the help!

Fivestar

JunJun

I have stock z28 wheels (7") and want to make a staggered style.
What do you think to using 235 60 r15 for the front and 255 60 r15 for the rear?
The 7" wheels make a good style with 255 for the rear?

Ron U.S.M.C.

Tire Rack says the 255/60r15 is in the 7 to 9in. range. That does not mean that a 7in.wide wheel should have that tire on it. The tire will have the side walls ballooning out more than an 8in. wheel. Look at the bottom of this tire and 8in wheel. Now imagine it with 7in. wide wheels. That's ballooning quite a bit.
A 225/60r15 front tire will give you a 25.6in. Diameter/tall tire. A 245/60r15 rear tire will give you a 26.6in. Diameter/tall tire. That's a 1in. rake. You can see the difrance in tire size in the bottom photo. and yours will have the same look with the tire sizes I have mentiond. That way you’re getting the staggered look you want and not pushing the 255/60r15 past IMO the limit with all that ballooning.

fivestar

Great info Ron! Thanks for the input, the old 'big & littles' look never goes out of style.

Fivestar

JunJun

Ron, thanks for your kind, detailed reply.

BTW, I have two worries.
One is, if I put 225/60r15 in the front, would it make a bit more space between tire and fender, which makes it a bit uncool for the standard height car?
I think the stock is 235/60r15...

Another is, with 245/60r15 on stock 15 inch rear wheels, will it make enough outward offset?
I know 235/60r15 with stock rear wheels don't make an appealing offset outward...
Do you think I need a spacer or something?

Jexter

I have a 1984 z28 Camaro with stock 15 inch rims when I bought it a year and a half ago the tires that were on it are 265/50/15's all way round with the rear inside wheel wells shaved off but fronts are not and my fronts fit fine I just purchased new 265/50/15 Hancook Ventures for my fronts and buying 295/50/15 (almost slicks) and will have enough room already measured.