1996 GTS 345/30RZ19 rubbing problem

[Ken Alker]

I purchased a 1996 Viper GTS a few weeks back that has Eibach springs and Koni shocks. The wheels are 19" HRE Performance Wheels all the way around (13" wide in back). I understand that this Viper had 17" rims stock.

The tires are as follows:
front: Michelin Pilot SPORT 285/30ZR19 (94Y) Radial X
rear: Michelin Pilot SPORT 345/30ZR19 (105Y) Radial X

I am having a problem whereby the back tires are scraping against the inside edge of the "fender" (the edge of the blue part of the body panel where it curls under the wheel well). This is shaving bits of rubber off the sidewall of the tire (starting at the top of the lettering going up to where the tread pattern starts).

I chalked the sidewalls and went out driving. I could not recreate the problem after standard city driving. The chalk gets smeared vertically when going over speedbumps, so I was hoping that was the only cause (cure: avoid speed bumps). However, I then accelerated quickly down a straight-away and noticed I took the chalk off in a nice ring pattern all the way around the sidewall, indicating that when I accelerate hard enough to push the back end of the car down, I get scraping.

I'm not sure how big of a problem this is, but I'm hoping to run at Willow Springs in a couple of weeks so I'm trying to come up with a way to fix it, if need be.

I spoke with Marc at HRE and he can mill up to 4mm off the back of the wheel, but this is costly, and he wants me to check the swing of the wheel assembly first which requires special tools, etc.

Another choice might be to cut away a little bit of the edge of the body panel where it curls under the wheel well (pretty well hidden).

Does anyone else have this setup on this car who IS NOT having problems? Please distinguish between Pilot Sport, Pilot Sport PS2, and Pilot Sport Cup in your response. Also, the "P" (or lack thereof) in front of the tires size seems to be relevant.

Has anyone else has had this problem and, if so, what did you do to rectify it?

Has anyone limited suspension travel to fix? How?

Has anyone cut away a little bit of the "fender"? How did you do it, and were you successful? Does anyone know what the body is made out of and what the best cutting tool might be? Maybe there is another way to solve this.

PM me if you want some higher res pictures. Forum seems to limit the size (thus, quality) of pictures I can upload.

Thank you in advance for any suggestions!

Ken

[Luke@tirerack]

345/30-19 is 27.1" tall a 1996 GTS is supposed to have a tire which is 25.9" tall. Basically what you have is a wheel and tire package that is spec'd out for a Gen 3 car

[SingleMalt]

The wheel offset is likely not correct for your car. I have CCW 505A's on my Viper -- same tire sizes as you, with no problems. I also noticed your ride is pretty low; maybe a little too much so. Are you having any bottoming issues?

[Viper X]

Hey Ken,

I don't think that we've met (you may have spoken with Cathy). I track my 01 GTS and have run many different tires and wheels on it, including those that you have on your GTS.

The most likely issue is an incorrect wheel offset, followed by too low a ride height and too tall a rear tire. As above, the GTS was not designed for a tire this tall. The car will feel and handle a bit differently with this tall tire on the rear - not in a good way either.

Do you live in the So Cal Area? If so, we should have a pretty good size group at Viper Days / Willow Springs next weekend.

Stop by our garage if you come up. Meanwhile, if you can raise the rear ride height and change the wheel offset, do so. Also, a bit more camber would help. You can cut the inside of the fender lip a little bit with a dremel tool, but be careful not to cut too much.

You'd be better off with 18-inch rear tires and wheels for the track or the street on this car. I have a couple of 18-inch used Pilot Sport rear tires in stock GTS sizes if you want them. $50.00 each.

Also, one of our San Diego guys has some track rims for sale. PM me if interested or check our local website at . : : SoCal Viper : : .

Dan

[Ken Alker]

Originally Posted by Luke@tirerack

345/30-19 is 27.1" tall a 1996 GTS is supposed to have a tire which is 25.9" tall. Basically what you have is a wheel and tire package that is spec'd out for a Gen 3 car

These are 27.4" (per Michelin tech support and web site). The stock tire was 26" tall (per Michelin tech; 26.22" per web site). In any case, the difference ends up being about 1.5" so I've lost about 3/4" between tire and fender due to larger tire. I've lost another 1" due to the Eibach springs. So, I've lost a total 1.75".

The wheels are 13" (just like factory), which amounts to 14" in tire width sidewall to sidewall (per Michelin tech). I forgot to ask what the originals were, but I'm probably sticking out further as well.

I purchased the car with the setup and I'm not sure what is considered acceptable (always stick with stock, or go wider but not taller, or go taller but not wider; put Eibachs on for performance; don't every lower car???), but my goal is to see if I can't make it work without having to start over again (ie. spending more money). Of course, if this combination (along with the Eibach springs and Koni shocks) is completely wrong for the car, maybe I have to start thinking about replacing stuff.

[Ken Alker]

Originally Posted by SingleMalt

The wheel offset is likely not correct for your car. I have CCW 505A's on my Viper -- same tire sizes as you, with no problems. I also noticed your ride is pretty low; maybe a little too much so. Are you having any bottoming issues?

I don't think I'm bottoming out. How would I know?

That is interesting that you are not having issues, yet have the same tire size. But, what is your wheel height and width (19" x 13" like mine, or something different)?

Also, have you modified the suspension at all?

[Ken Alker]

Originally Posted by Viper X

Hey Ken,

I don't think that we've met (you may have spoken with Cathy). I track my 01 GTS and have run many different tires and wheels on it, including those that you have on your GTS.

The most likely issue is an incorrect wheel offset, followed by too low a ride height and too tall a rear tire. As above, the GTS was not designed for a tire this tall. The car will feel and handle a bit differently with this tall tire on the rear - not in a good way either.

Do you live in the So Cal Area? If so, we should have a pretty good size group at Viper Days / Willow Springs next weekend.

Stop by our garage if you come up. Meanwhile, if you can raise the rear ride height and change the wheel offset, do so. Also, a bit more camber would help. You can cut the inside of the fender lip a little bit with a dremel tool, but be careful not to cut too much.

You'd be better off with 18-inch rear tires and wheels for the track or the street on this car. I have a couple of 18-inch used Pilot Sport rear tires in stock GTS sizes if you want them. $50.00 each.

Also, one of our San Diego guys has some track rims for sale. PM me if interested or check our local website at . : : SoCal Viper : : .

Dan

Marc at HRE Wheels claims that my wheel and tire setup is the "conservative basic standard fitmit" for my car. I believe he said they've done around 1000 of them with no problems. However, he doesn't have feedback on this package with the Eibach springs, which certainly could make all the difference.

Even though he can mill up to 4mm off the backs, HRE wants $600 to have it done, plus he wants me to take my car in to ensure the tires end up hitting on the inside once offset - smart, but not easy around here. I'm starting to lean toward shaving the inside of the fender a little since its something I can do myself (without driving hours to get rims worked on, no cost, less time, less hassle). Although, I'm nervous about hacking on the car. What type of tip should I use on the dremel? I'm thinking of trying an 18K RPM air grinder with a deburring bit. Do you know what type of material that fender lip is made of?

I live in S. Cal (Goleta, just north of Santa Barbara) and will be at Willow Springs this weekend. I'm afraid I really don't know how to raise the ride height - is there an easy way to accomplish this? I hope these tall tires don't mess up the ride on the track. I wonder why they changed them in the first place.

[SingleMalt]

I really think you should STRONGLY consider not making any modifications to the body of the vehicle. As Dan stated, if you're going to take it to the track, the 18" option is really the best way to go. The vehicle responds well to the geometry of an 18" tire and the little extra sidewall helps with yaw control.

My wheels are the exact same size as yours and my ride height has been reduced by about 3/4" in the rear -- when I switched to the 19" wheels I brought the rear-end of the car up to manage the new tire size better. With 17/18" wheels, 1.5" drop in the rear is typical, but you make some of that up with the larger tire radius on a 19" wheel, so it's best to raise it up a hair. If you have stock coilovers, this process is not fun for you; you will either need to change the springs or add a 1/2" or so spacer.

Have you brought the car in for an alignment? This is a MUST once your car is ready for the track. I'm not sure if there are many places that can properly align a Viper up your way. You can start by calling Todd at A&C Performance in Murrietta or Dan at DC Performance in LA. Heck, maybe that's the best way to get the ball rolling. Let them take a good look at exactly what's going on with it. The last thing you want is a silly cut tire to ruin your track day -- and possibly your car!

Have fun and be safe, man.

Mike

[Ken Alker]

Why is your ride height reduced 3/4"? Different springs?

When you got the bigger tires, did you add the spacer?

I have not had it aligned, but *to my knowledge* the previous owner had the package put on by DC Performance, so, if that is true, hopefully it was aligned then.

Does it need to be aligned differently for track and street?

Can Archer check alignment at the track? I can't get down to LA before the weekend.

[grcforce327]

Originally Posted by SingleMalt

The wheel offset is likely not correct for your car. I have CCW 505A's on my Viper -- same tire sizes as you, with no problems. ?

Bingo!! I'm running that size tire on my gen I with Aldans and the car lowered with no issues!

[SingleMalt]

I have aftermarket coilovers which have adjustment collars on them to easily adjust ride height. If you have a stock setup, there is no easy adjustment for this. When I changed to the 19" wheels, I was able to choke the collar up to make up for the different tire radius.

Frankly, I'm surprised DC didn't catch the potential clearance issue. I would take it back to them and see if they think it's a straightforward fix. As far as the track day, I would post on the board and see if anyone can bring a set of 18's for you to switch to at the track. I think you'll be pleasantly surprised by the responses you get.

Mike