I will give a little background on a little problem I have been having with tire wear... Last year when I drove to Bowling Green and back I noticed that my inside front tires had started to cup real bad on the inside.. I figured that my stock deCarbons had bit the big one since my car had been lowered sometime ago. No problem.. I parked my car for the winter and bought some revalved Bilsteins from Sam Strano to handle the lowering... After I installed the shocks in the springtime I went down to get a wheel alignment.. 5 degrees caster 0 degrees camber 1/16" toe-in I then rotated my cupped tires to the back After driving around for part of the summer I noticed that my front tires were again starting to cup on the inside the same way as before... Now I do realize that a vehicle will naturally toe out when driven.. After noticing that my tires were cupping I took my car down to get aligned again to see if that was the problem.. They were a little out but not much.. We then put the car back to the specs I mentioned earlier...
Now after this long rambling here is my questions...
What could be causing my tire wear?? Is there something worn out that would cause my car to toe out when driving?? I will be going to Bowling Green again this year and don't want to have to buy new tires when I get down there...
Thanks for everyones help in advance....
[ 26. August 2003, 10:28 PM: Message edited by: CK-1 99SS ]
Posted by JeffY (Member # 120) on :
First question-what tire pressures are you running?
Posted by CK-1 99SS (Member # 93) on :
34psi all around
Posted by JeffY (Member # 120) on :
That's a little high - should be closer to 30 -the 4 psi can make it ride a lot stiffer. As far as the cupping - page the local tire expert, KenC - that's his field of expertise.
Posted by 2002Z4CSS (Member # 1393) on :
Is the 1/16" toe in factory specs? These newer cars toe is ususlly measured in degrees instead of inches.Your camber is great even with the lowered ride height.Caster is 5 degrees positive I assume.That is great. Posted by Bill Mason (Member # 1807) on :
Hhhmmm...this is a tough one. I would say that tire pressures are not a factor, since if they were too high the centres would wear more than the edges. Also, performance tires need a little more pressure. I run mine at 34-36 psi.
I assume that the front end shop checked the outer tie rod ends and they are tight. You may also want to have the inners checked as well.
Past that, I would then look to see if the wheel bearings are loose. They are a weak link (IMHO). In 157,000 kms I am one my 4 or 5th set....lost track.
The last thing to check is the upper and lower ball joints, but I would be surprised if they are the culprit.
You might want to try zero toe-in as I have tried a small amount of toe-in and I did not like the way it deadened initial turn-in. This would not be causing your tire wear problem as you noted.
One other thing you can do to even out tire wear is to remount the tires so the inside becomes the outside on the other side of the car. This is sometning I have been doing.
Bill M 98 TA
Posted by JeffY (Member # 120) on :
quote:Originally posted by Bill Mason: Hhhmmm...this is a tough one. I would say that tire pressures are not a factor, since if they were too high the centres would wear more than the edges. Also, performance tires need a little more pressure. I run mine at 34-36 psi.
Bill M 98 TA
I agree - I don't think its a tire pressure issue. However, you are incorrect about performance tires needing more pressure. The F-car was designed and tested with the Z-rated tires at 30 psi-that's what the the ABS, ASR and suspension were tuned for. 34-36 greatly reduces the footprint of the tire.
Posted by 35th6spd (Member # 1243) on :
I was an alignment specialist for 6 years; I never once observed tire cupping on only one side of the tires due to tire pressure or bad wheel bearings; most of the time I observed bad steering linkage components (tie rod ends, center link or idler arm) permitting excess travel or bad shocks/struts with weak springs; I believe it is unlikely that your alignment settings are the cause, because the tires are cupped, not worn, and only an obvious misalignment (extreme toe out for example) will cause this (camber generally wears tires evenly along one edge of the tire, as does moderate toe misadjustment). I would suspect worn inner or outer tie rods, allowing excessive toe out on turns as the culprit;;;however, it is unlikely a good alignment shop would perform an alignment without first checking the suspension for tightness..??..good luck
Posted by poSSum (Member # 119) on :
These are your KD's? By "cupping" do you mean a wedge shape worn off the inside tread blocks?
That's what I have, but blame it on a fairly agressive autocross biased wheel alignment.
Wouldn't expect it with your alignment.
You Autocrossing in Bowling Green? If not I have set of 16" skinnies for the front you could borrow if you don't solve the problem ... . . . . . . . . and some DR's Posted by CK-1 99SS (Member # 93) on :
Thank-you guys for your help.. I am going to take my car back to the alignment shop one last time to check everything over again.. I am right there each time and we check for play in all the components... By cupping I do mean that a wedge shape is worn off on the inside...
Art- Yes they are my KD's and I might take you up on that offer.. as far as the drag radials I am just to chicken to put them on as I am not sure my stock rear can handle it.. I have some Nitto DR's at home that I am going to put on after the BG trip to see if I can touch the 11's..
Thanks again everyone for your help...
Posted by DGOETZ (Member # 1846) on :
Are you running a Strut Tower Brace? If these point were to fold or move in would this not effect tire wear?
Posted by 2002Z4CSS (Member # 1393) on :
quote:Originally posted by DGOETZ: Are you running a Strut Tower Brace? If these point were to fold or move in would this not effect tire wear?
If for some reason the shock towers would get old and move inward,that would effect the camber big time.Like it did on the old Chevettes that had rusted shock towers...the tires had a ton of negative camber.Good for a Winston Cup cup car but not good for a street car. Posted by SS_CarGuy (Member # 2065) on :
Cupping is almost always caused by loose or worn suspension/steering components. Make sure everything is checked out thoroughly. The only other possibility is tire imbalance.......but you should be able to feel that. Combine this with worn or loose suspension/steering components, and you will get cupping.
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