jeffp1167

Stock I think it came with 235/55/16 tires which seem to be an oddball size and not a great selection to chose from. My wheels are the star looking chrome ones which look just like a Z-28 wheel will the larger Z-28 tires fit my rim or did the Z-28 use a wider rim?

I believe the wheel to be a 16x8 but I am not sure. I am also open to tire & wheel packages like ZR-1 style for the car but unsure of the correct offsets to use.

Being this car is of the obd2 will tire size changes affect the transmission shifting or could I mount say 245/50/16 tires on and the ecm would not notice? I can't imagine a 5mm difference in sidewall height would mess the speedometer up to much.

Anyone who has done ZR-1 rim swaps on a 4th gen f-body chime in. One reason I am opting for rim replacement is that it is believed the chrome is damaged on my inner wheel bead area and this is causing my tires to lose pressure all the time.

leadfoot4

In all honesty, I think that A) your car's PCM is calibrated for the 235/55's overall diameter, and B) if the car had the 235/55s as OE, the car has a speed limiter in the PCM, as they aren't "Z" speed rated, as the optional 245/50s were. I think the limit is 118 MPH.

I have a '96 Z-28, and since I ordered the 245/50s on it when new, the car has no limiter, and came with 16x8" rims. Over the years, I've had the 245/50s on 16x9.5" rims, 225/55/16's on the 16x8 rims, and currently have 275/40/17s on 17x9.5" rims. The computer was OK with this, as they are all basically the same OD. (you can get repro ZR-1 wheels in 17x9.5" in the correct offsets for f-bods)

I think you could have the PCM re-programmed by someone like "PCM for less", and they could set it for the smaller OD of the tires, and pull the "governor"....

Raven02TA

you can safely go with a 245/50-16 as long as the tire is a factory 26" tall you will have no problems

your shifting/pcm calibration will not be affected by going with a Wider tire. the only thing different that will happen will be better traction :-)

there is no difference in height between the 235/55 and the 245/50 they are both 26" tall

jeffp1167

Thanks I'm looking at Nitto tires for it ... Yes the car is governed but it isn't till about 123mph. Could chevrolet do the PCM recalibration on the car? Also what ride difference will happen. This car is pretty harsh riding as it is, it does have some performance package on it. So these rims would definitely be 16x8? I purchased the car new so these are the rims that originally came on it.

jeffp1167

Not a picture of my car but these are the kind of wheels on it.

RapidRick

Looks like you have the chrome versions.
Ditto on what "Raven" said on being good to go with the 245/50x16" size.

jeffp1167

Yes they are the factory chrome ones. I'm curious why they started leaking like they do. They have been off the car and submerged and no leaks found and this was on all four of them. At first I thought it could have been someone just letting the air out but this isn't the case since it did it one night in the garage. I don't see any signs of peeling chrome near the bead area nor is there any curb damage. I even had the bead wheel weights removed and that did not cure the issue.

This basically all started after I had tires (bf goodrich) installed at Big O tires .... Have any of you had issues with bf goodrich tires doing this? Or is it my rims were damaged during tire installation? Another thing I noticed just recently these tires massively started weather cracking close to the wheel bead area yet they were put on the car maybe 2 1/2 years ago at the most. Isn't that odd for them to do this at this age? I have much older tires on another car that are not doing this.

Silicone was once applied to the wheel beads which it did stop the problem but then it started happening again.

So have any of you had problems like this with chrome wheels? I really hate to spend the money on another set of wheels for the car but I do not enjoy getting off work and it has a flat tire!

RapidRick

Yes I went thru this on a '98 T/A I had. At about 7 years old. (No saltwater submersion, etc). I had to start adding air to the left frt tire every 3 weeks as it started to really show the loss of air.
I didn't use this car as a Daily Driver, but more like weekends. I was at a loss as I had GoodYears on it.
Had the local Goodyear Center put tire & rim thru all day "water troft" leak test. Dismount & remount. Bead sealer, Cleanups, swap the tire in question with the rear wheel which wasn't leaking to check if tire was actually the culprit. It wasn't. (Problem Lft.Front tire didn't leak when put on my left rear wheel, but rear tire now on "lft. front suspect wheel" kept leaking!)
I did this over the course of about 1 year. Never found the problem. Since my NBM T/A wasn't used much, We just lived with adding the approx 20 lbs. needed every 3 weeks or so. ( I ran it at 36lbs. and sometimes a 2-4lbs. more since I new air would leak anyway...lol.)

I Finally bought another used Rim. after 2 yrs or so of this. Remounted tire. No Problems after that!
Only that one wheel. (An original from my car, 16" Chorme GM Factory type Firebird wheel).
It's a "hit or miss thing" as after I bought the 1 wheel, I sold the T/A about 11 months ago, and there hadn't been any other problems with the other 3 original wheels, nor the one I bought used and had put on.

My guess is what is hard to take, but what I came to find out.
Your wheel(s) are "pourus". Leakdown occuring at some minutia pinpoint.
Best regards on your quest.

jeffp1167

That is the wheel that is the problem on my car as well. In one corner of one of the (spokes) there is a very small area of the chrome peeling. This car is also not abused or a daily driver & all I have every cleaned the wheels with is sos pads to removed the caked on brake dust but have never used chemicals to clean them. The rims still look brand new and have about 86k miles on them and this is a california car and its never seen salt or anything and even rarely see's a rainy day. I've never tried switching them to another rim or rotating though one place had thought when the car is stopped and pressure is on a certain point on the rim that is when the leak occurs. Yet another said it could be due to the chrome retaining so much heat that it affects the wheel beads area to seal.

Sorry I meant mine is on the right front.

jeffp1167

I just found this article about chrome wheels having sealing issues. I will have my beads really looked at and see if they are corroding under the chrome.

http://www.whlworx.com/Chrome_Wheels_Loosing_Air.htm