Rear tire wear

TurboGT · Post by **TurboGT** » Mon Sep 19, 2005 9:24 pm

This is the 4th Fiero (all pre 88) I have owned and all of them seem to wear the rear tires quite fast. I have different size tires fornt to rear so I cant rotate them. The tires are wearing evenly accross the tread, just at a much faster rate than I think they should.

Is the tire wear caused from the toe change when going into corners?
Are the 88's better at not wearing the rears so fast?
Is it because the car is rear wheel drive and while turning the inside wheel wants to turn at a slower speed than the outer?
Is there something I can change when getting it aligned (like the alignment specs)?

teamlseep13 · Post by **teamlseep13** » Mon Sep 19, 2005 9:34 pm

Assuming that your driving style isn't like the Dukes of Hazard, a good alignment shop should be able to figure out the right specs to help keep your tire wear down.
Alot also depends on what tire you have. Some wear a shitload faster than others. Check the treadwear rating, and if its below 300, thats probably the problem.
Toe change during cornering will wear tires faster, but unless its a real huge change it shouldn't be doing it fast. Plus if the toe change is that big, you would notice the terrible handling first. As for being pre 88, sure that will make a differnece because the bumpsteer in the rear of pre 88's is a problem.
Since the car is RWD, of corse the rears will wear faster than the fronts, same with FWD but reversed. But it shouldn't be very noticable, where you are having to replace 2 sets of rears for every set of fronts.

What are your alignment specs now, what kind of tires do you have)size and all) and whats the differnece in tread wear between front and rear.

Post by **eHoward** » Mon Sep 19, 2005 9:47 pm

post pictures of the tire wear.

TurboGT · Post by **TurboGT** » Mon Sep 19, 2005 10:32 pm

Tires are Road Hugger- Radial GT-A's
Front: 205/60/15
Rear: 215/50/15
Tredwear: 380 Traction: A Temp: A
I have no clue to what the alignment specs are set to now. The reason I asked about the specs is because I have a gm update on the 84-87 Fieros. It says that you should change the rear toe from
.15 +/- .1 degree (per wheel)
to
0 +/- .1 degree (per wheel)
I know this isnt much but was just wondering.
I would say that the rear tires are 50% of the fronts. I dont know how old these tires are, I got the car 6 months ago and the rears have just seemed to go fast. These tires havent even been on the car the whole six months I have had it, I had some 18's on her for at least a month of that, and those seemed to be wearing fast to the rear also. Here are some pics, sorry it was starting to get dark so they dont look the best

Front tire

Rear tire

Shaun41178(2) · Post by **Shaun41178(2)** » Mon Sep 19, 2005 10:45 pm

your tire wear looks even. THey are just the drive tires man. THast the way it is.

I have an 88 and mine do that too. I dont' do burnouts either. I take off normally from every light. Mine on the rear have slightly more wear thent he fronts. I have had the tires on for like maybe over a year now.

TurboGT · Post by **TurboGT** » Mon Sep 19, 2005 11:12 pm

How often would you guys say you have to replace the rears compared to the fronts?

stimpy · Post by **stimpy** » Mon Sep 19, 2005 11:24 pm

I'd say 3 sets of rears for 2 sets of fronts.

Kohburn · Post by **Kohburn** » Tue Sep 20, 2005 8:27 am

stimpy wrote:I'd say 3 sets of rears for 2 sets of fronts.

for me on past fieros running 235's in the rear and 225's front i'd go through 2-3 sets of rears to one set of fronts (running a rear sway bar)

The Dark Side of Will · Tue Sep 20, 2005 8:36 am

255's rear, various from 205-225 front. About two sets of rears per set of fronts.
The harder the pedal hits the floor, the faster your rear tires wear out.

TurboGT · Post by **TurboGT** » Tue Sep 20, 2005 9:34 am

The problem with the early cradle is that the bump steer is for front wheels, that is the further the suspension moves up the more the tire toes out. This cause the trailing throttle over steer. As the car slows down in a corner weight shifts from the rear to the front, the rear suspension moves down in relation to the rest of the car. This causes the tire to toe in, and increase the slip angle requirement with less weight on the wheel. This leads to the tire slipping and the car spinning around.

Also in the early cradle as the car increases speed in a corner the weight of the car shifts to the rear. This cause the rear suspension to move up in relation to the car ( the suspension compresses ). This causes the wheel to toe out. This causes rear steering in the car.

http://www.mindspring.com/~martinwhite/ ... index.html

With the above would you say that the 88's are better on rear tire wear?

The Dark Side of Will · Tue Sep 20, 2005 7:51 pm

Other than reducing how often you spin out in hard corners, no.

teamlseep13 · Post by **teamlseep13** » Tue Sep 20, 2005 8:21 pm

Toe change will affect the tire life, in a straight line and during the corners.

While moving straight ahead, the wheels should have no toe for the best tire wear, but normally they have a small amount of toe in, which is a more stable condition when you encounter a corner.

But I still think its probably just normal RWD rear tire wear. Yes it sucks, but yes RWD worth it.

Kohburn · Post by **Kohburn** » Tue Sep 20, 2005 8:22 pm

teamlseep13 wrote: But I still think its probably just normal RWD rear tire wear. Yes it sucks, but yes RWD worth it.

fwd wears out the fronts fast - difference is you can rotate them easily

teamlseep13 · Post by **teamlseep13** » Tue Sep 20, 2005 8:26 pm

True, but FWD blows.....hehe

TurboGT · Post by **TurboGT** » Wed Sep 21, 2005 12:18 am

Thanks for all the input guys

The Dark Side of Will · Wed Sep 21, 2005 8:56 pm

Kohburn wrote:
teamlseep13 wrote: But I still think its probably just normal RWD rear tire wear. Yes it sucks, but yes RWD worth it.
fwd wears out the fronts fast - difference is you can rotate them easily

Not necessarily. New Grand Prix GXP's (with 5.3 V8) will FINALLY have wider tires in front than in back.

crzyone · Post by **crzyone** » Wed Sep 21, 2005 9:45 pm

How much do you think that transverse sbc and trani package weighs? Seems like the weight bias in the new GXP would be terrible.

Kohburn · Post by **Kohburn** » Thu Sep 22, 2005 8:02 am

The Dark Side of Will wrote:
Kohburn wrote:
teamlseep13 wrote: But I still think its probably just normal RWD rear tire wear. Yes it sucks, but yes RWD worth it.
fwd wears out the fronts fast - difference is you can rotate them easily
Not necessarily. New Grand Prix GXP's (with 5.3 V8) will FINALLY have wider tires in front than in back.

interesting - int he fwd cars I've owned most of the wear was from turning and braking (not necessarilly at the same time)

The Dark Side of Will · Sun Sep 25, 2005 10:37 pm

teamlseep13 wrote:Toe change will affect the tire life, in a straight line and during the corners.

While moving straight ahead, the wheels should have no toe for the best tire wear, but normally they have a small amount of toe in, which is a more stable condition when you encounter a corner.

But I still think its probably just normal RWD rear tire wear. Yes it sucks, but yes RWD worth it.

The difference in bump steer between early and '88 suspension will not make one iota of difference in tire wear... Except, as I said above, in reducing the frequency of embarassing spinouts.

The Dark Side of Will · Sun Sep 25, 2005 10:37 pm

Kohburn wrote:
The Dark Side of Will wrote:
Kohburn wrote:
teamlseep13 wrote: But I still think its probably just normal RWD rear tire wear. Yes it sucks, but yes RWD worth it.
fwd wears out the fronts fast - difference is you can rotate them easily
Not necessarily. New Grand Prix GXP's (with 5.3 V8) will FINALLY have wider tires in front than in back.
interesting - int he fwd cars I've owned most of the wear was from turning and braking (not necessarilly at the same time)

Did most of the FWD cars you owned have over 300 ftlbs of torque?