Directional tire question

[me and my metro]

Thanks for the update. Back when I was racing cars in the 70s we always adjusted the suspension with the weight of the driver in the car. We also could adjust the suspension to compensate for fuel load on short or long runs. Street cars have really soft spring rates and iffy shocks. They bounce off the suspension snubbers all the time. Better shocks and stiffer springs with a good alignment can do wonders for handling and tire wear.

[freebeard]

I just ran across this tonight looking for something else.

I know how that goes. I just read the thread for the first time.

What I was looking for mention of was the rear wheel alignment. I did see some mention of rear toe-in. The best alignment I got was from a street-rod shop (long since gone) and it was $200 for the front and rear. It made my Type III Notchback as nimble as a little ballerina. Gymkana racers like toe-out in back because it wants to go around corners. If you drive long distance at night, toe-out.

It's a little after-the-fact, but if there're bald spots, you might as well shave the tire round[er] because the extra tread is causing problems and will never be used anyway.

[hotshoetom]

Originally Posted by CapriRacer

If you read my blurb on alignment, you probably figured out that I think anything over 1° of camber results in irregular wear - and that's the srtuation here.

Yes, Kia's specs for the rear can result in over a degree of camber, and that is clearly going to result in tire wear problems. But Kia's warranty doesn't cover tire wear in any way, shape, or form, so don't be surprised if get the cold shoulder for the Kia dealer. To complicate matters, getting an alignment somewhere other than the dealer could be used as evidence that there used to be a problem.

A better bet is to find an alignment shop that will work with you to get the alignment where you want it to be rather than what the book says.

I agree with everything he said...and let me add just a bit more to this. I have much autocross experience and a lot more experience specifying my own alignment specs over the years. I can sum up that experience in just a few sentences. Anything over .5 degrees of camber at either end of the car will result in uneven tire wear on a conservatively driven street car. If you are an aggressive driver cornering near the limit on a regular basis, you can push that number quite a bit higher and maintain nearly normal tire wear. Most of us dont drive that way so go outside the 1/2 degree window at your own peril. The other major contributor to tire wear is the toe setting. try running zero toe front and rear and as close to zero camber as you can get. By all means balance the camber side to side so that the front tires have the same camber and the rear have the same. more negative camber in the front will help alleviate understeer and on most front engine cars that is what you want. Rear engine cars are another category and they have their own requirements. I think if you follow these general guidelines you will see your tire wear improve dramatically.

[freebeard]

It's interesting that the aggressive driver gets more even wear. ...until they start drifting.

I'd add a little toe-in in front to compensate for any slop in the steering linkage.