BigBiscuit

i run 235/60/15s on my IROC daily driver now. If i upgraded to 245/50/16s on original IROC rims would the difference be noticeable? i don't think it would. anyone have an opinion?

coolram62

iTrader: (2)

I have done a similar swap on my '83 Z28.I had the original 15x7 gold 5 spokes with 235/60R-15 Uniroyal Tiger Paw GTS all around.I switched to single stripe gold IROC 16X8 with Sumitomo HTR-H4 235/55HR-16(same size that came on most convertibles).With just this change I noticed turn in was a bit sharper(seat of the pants)than with the 15" package.The difference you may have will come down to which tire you decide to use.I would eventually like to find 2 more front 16" gold wheels to make rotating easier.

Since this swap I have been working on upgrading the rest of the suspension to take even more advantake of the wider footprint and better handling characteristics.

The Project

iTrader: (6)

I just finished swapping out my 15's for 16's (b4 the fuel pump went south). Steering feels a little bit more responsive. Like the way it feels............

avro206

I did this before, went from 15's to 16's

Big difference. Car could corner alot faster and it looked better. 235/60 is a tall sidewall for 3rd gens, IMO

coolram62

iTrader: (2)

A 235/60R-15 is basically the same height at 26" as the 215/65R-15(standard tire size for the Z28 '82-'87) but giving about a 1" more footprint(depending on rim width).Some have 255/60R-15 and even 295s.

As stated before going to 16" rims gives more foot print.The result being quicker response depending on tire choice.And it also gives you more choices in tires with the choices in 15" tires shrinking(performance tires that is).

1987Rock

I've been running the exact same tire size (235/60-15) on some rallyes on my IROC for a while now. I had 245/50-16 on my IROC wheels before and I hate the 15's. The ride is a little rougher because of the shorter sidewall, but the performance is much better with the wider tires.

BigBiscuit

thanks for the responses. i didn't expect there would be a difference, so i appreciate you all posting comments.

1988-305-tbi

i went from 235/60/15 to 245/50/16 last summer, and sterring response/ predictabilty doubled definately a great upgrade, now i wonder what 17 or 18 inch rims might do

Sonix

iTrader: (1)

I don't like 16" wheels for a few "consumer" type of reasons.
-tires are more expensive when you go to a larger wheel
-the selection for WIDE, drag racing type of tires is non-existent on 16" wheels.

I have 235/60/R15 on the front of my car, and 275/60/R15 on the back, on 15x8 snowflake 2nd gen wheels. I think the fronts could be better to allow better handling, I can't argue that.
But if I went to 16x8" wheels, there is very little selection when it comes to tires wider than 255. I was hoping to find a 275/50/R16 or so, but it doesn't exist.
So i'm sticking with my 15" wheels, and enjoying the cheap fat-boy tires.

Azrael91966669

well i had stock 15 inch rims on my rs but upgraded the swaybars and if id take a corner hard with the 15s the front would Slide
just up gradeing to 245-50-16s let the car grip the road with alot of force

tires on the 15s where 225 60 15 dayton daytonas HRs

tires on the 16 where 245 5016 cooper cobra hr

the side wall flex has a lot to do with it
why you see lots of imports rideing on 18s with what looks like no tire

no sidewall flex greatly improves cornering

one thing is yes for the most part 16s be it 235-55-16 or 245-50-16
tend to cost almost 25% more then most other tires as so few cars used this size other then f-bodys

even 225-50-16 would be an upgrade for cornering but the side profile is very thin

Apeiron

You can't fit a wide tire on a stock 15" rim anyway.

Azrael91966669

ive seen 275 50 15 on the stock 15 inch rs rims
ill admit the tires looked like they where gonna blow off but the guy said they never gave him any problems he had 255 60 15 front and 275 50 15 on the back
ive also seen many people use the stock 15s for drag slicks

Apeiron

He might not have had any problems, but he would have had better performance with a tire that fit the rim properly.

Sonix

iTrader: (1)

oh yea, I meant if he was thinking about getting 15x9's say, or 16x9's, i'd do the 15's so at least you have some selection for a fat drag tire.
If you'd prefer handling, then it's a different matter.

Yea, in theory. You need to make sure the suspension matches it though.
My buddy put 18's and rubber band tires on his V6 camaro once. Think about a rock skipping on a pond... I'd rather have a nice semi-controlled slide, than skip across the road...