What is the largest 60 series tire that you can put on a 1990 IROC with a 15x7 wheel?

I was thinking of going 235/60/15 for the fronts and 255/60/15 for the rears, but now I'm getting kind of cocky and was wondering if a 265 or a 275 would fit on the rear without rubbing the wheel wells at all. I was thinking that it would give it a nice looking stance, along with some added traction.

Anyone have any pictures of their sizes for reference at all?

 

i have 275/60/15 futura super sports on one set and 275/60/15 m/t ET Street Radials on another set. they work great and look good too. these are on the stock 15x7 5spoke z28/rs wheels. you will have to do a little massaging on the inner fender well to get them to fit without rubbing, but it's not too bad at all.

kinda hard to see in this picture, but you get the idea, 275/60/15 m/t's out back and 205/70/15's up front:

 

I am liking the look of the 275. You said that you have to do a little massaging to get them to fit....what do you mean by that? Do you find that they rub with a load in the back seat at all? I'm just afraid if I have a passenger or two in the back that it will cause the back to sag down a bit and rub the tire.

 

my car has trimmed springs, so it's already a bit lower than stock. the rubbing is on the lower/front portion of the wheel well by the lca. you'll see what i' talking about. 5 mins with a hammer and your done. no need to roll the fender lip or anything like that though.

my car doesn't carry much around other than myself and sometimes my g/f. my helmet is a permanent installment in the backseat, just incase....but that's it. want to always keep the car in it's lightest state, regardless, the top of the well isn't the spot that needs to be worried about.

 

I ran a set of 275/60/15 in the rear on my old 85 camaro. I only had them rub if you take a really hard turn at speed. Or if you nail a set of railroad tracks or pothole really hard. But the car was a berlineta. It had a 350 swaped into it. But the rear springs were still the soft v6 ones. So that's why it would rub on hard turns. But it was also not lowered like the z28 or iroc ones. So that probaly helped when I had 5 people in the car. Adam :-)

 

here's a better shot:

 

28 x 10.50" x 15" mickey thompsons on stock 82 83 84 finned aluminum cast trans am wheels on the 82 Z28 and theyre horrible, the back of the car is very unstable with them,

the tires are like jello

junk

gonna go with narrower or shorter ones

probably jut shorter, about 2" or so less,

to help get a little more rpm sooner on take off, also put the back end a little lower maybe a little more weight towards back there

sidewalls is where to watch

mine have plenty of room with the 10.50's both to the wheel lip, and on the inside of tires to the tub
no chance of rubbing at all





good luck

 

Im running stock 235/60/15 tires on the front and 255/60/15 tires on the rear on my stock 15x7 wheels on my 85 T/A. Looks great. Fits perfectly. Unfortunatly I dont have any pics since I put those on.

 

I run similar - 235/60 15 up front and 255/60 15 rears:

 

difflock... I want your car... I really miss my '83 and I've been looking for a similar vintage hard top, non aero package TA to swap all my good stuff into.

I had the same tire sizes on my '83 TA but the car was lowered probably close to 3"

 

BTW, largest... you can go quite large, I run 275/60/15 BFG dr's on my formula on some firebird 15x7's with no issues, and that thing is lowered quite a bit also, I've posted pics of it around here a few times.

 

Make him an offer, but i bet he refuses.
Mines the same car, but not quite as nice, at least now you know where all the old 83 models went.

 

Damned Brits… you’re hording all of them


Heh, here it is more my style, sorta the anti TA (mine was white), but lowered and cleaned up a lot like mine was:

 

I just put on some 295/50/15s on my car. They are on 15x10 Weld Prostars. took some massaging with a hammer and tubular lower control arms will be a must.

 

Backspacing/offset? Pics?

 

I think they are 5 1/2 backspace.

My Car

 

Can you check? Judging from those pics I’d be shocked if those were 10’s with 5.5 backspacing and tucking in that far. Maybe 8’s with 5.5 (though the tires would normally bulge more) or 10’s with 6.5” (but I wasn’t sure if they’d fit, which is why I’m trying to get details)

 

I will try to check this weekend. your right they might be more then 5.5 backspace. it did take a bit of beating in the inside to get them on there. right now there is a 3/8 wheel spacer on there also. I was in a hurry to get the car home that night. the wheels are off one of our other drag cars. I am sure they are 10s, we did measure that.

 

very cool ride NHRA427! i like it alot! are you planning to keep it a sportcoupe or go with the gfx like everyone else? i have a no gfx car and love it. check it out at www.preacherskid.jamaministry.com you can see where i ran a 295/50/16 on some irocs for a little whiel, but i'll be putting my 275/60/15 M/T ET Street Radials on it for a while till i can get another set of wheels/tires. (sold the irocs for some cash for the new motor)

 

You want to sell me them?

 

It looks like they are a 6" backspace. I measured from the brake drum to the inside of the front lip and its 4". If they were 5.5 they would have fit better. with these you have to cut that metal by the coils springs and pound that seam in the fenderwell in a lot. also even with the 3/8 spacers it rubs on the LCA. I had to trim the lip of them to get the car home. I am going to go with tubular control arms, that should give me the clearance I need. And i am going to cut the lip in the fenderwell out and reweld it smooth. I dont know about the GFX stuff. If I did go that way it would be the last thing I do. Always wonder what it would look like with just the Z-28 front end only.

 

don't listen to mw66 about the gfx He's a closet gfxer , sorry had to do it. As far as just runnning the z front end, as much as i am a gfx fan i would have to say no, the difference in body lines just makes the car look lost somewhere in the middle. Good luck with the ride though, btw I am running 28x9 with a 15x8 with 4.5 bs. The old car was running 275's with a 15x7 with no rub issues.

 

Are you saying that if you cut out the countoured areas on the inside they'd fit without the spacer (that's what I'm guessing would work, and that a 5.75" backspacing would work with only massaging the inner...).

what about the outside lip, does that hit? Is you car lowered at all?

 

Mines not lowered and the outer lip wont rub. It would if it was lowered. I would think rolling it would work. And yes the countoured area must be cut out. I think with a 5.5" back space should be ok just to pound the area out of the way. Also the metal between the coil spring and the tire must be moved in a little.