what causes a tire pull

[2.2 Straight six]

Originally Posted by Polygon

Lots of things can cause tire pull.

1. Uneven tire wear.
2. Out of alignment.
3. Directional tires put on the wrong way.

Those are the most immediate offenders. Here's a tip for you. When you rotate your tires always rotate them from front to back. The criss-cross method was used for bias ply tires. Also, you CAN'T rotate directional tires criss-cross or it will mess up how your car rides.

very rarely does a directional tyre running backward cause a pull effect. you only really encounted adverse effects when a directional tyre is running backwards in heavy rain. in the dry there is little difference. as directional tyres (like non-directional tyres) are symetrical the sidewalls and carcass are the same either side.

inside-outside tyres can cause problems if fitted the wrong way round, as some are manufactured differently side to side, for example stiffer outer sidewalls for cornering ability.

most cars will pull to one side when you let go of the wheel for a simple reason. roads are built with a camber, to direct water towards the pavements. in my shop i had customers return to the shop after having alignment done, claiming the car pulled to the left when they let go of the wheel. of course, in the US it would pull to the right.

tyres alone don't usually cause a car to pull, unless odd sizes are used on the same axle.

[bobss396]

Originally Posted by 2.2 Straight six

...most cars will pull to one side when you let go of the wheel for a simple reason. roads are built with a camber, to direct water towards the pavements. in my shop i had customers return to the shop after having alignment done, claiming the car pulled to the left when they let go of the wheel. of course, in the US it would pull to the right....

Yeah, the road crown thing you describe is right on. After alignments, we always would road test the cars on this long level stretch of parking lot that was close by. Get up to 30 or 45, do a "hands off" test and see how it went.

Most of the time we were able to fend off a complaint by explaining the road crown thing to the customer and having them drive it on our private "test track" or the bigger highways, as they were built with no crown.

Bob

[UncleBob]

thats why there should always be around half a degree less caster on the left side for right side driven cars. Corrects for most crowns

Some cars are more sensitive than others. I've seen cars with as much as two degree's caster difference that didn't pull. Lot of geometry factors and stiction in the steering system.

[Deepdoodoo]

Thanks for all the help. The tires in question are BFG Touring T/A with about 6k miles. I don't see any rotational arrows on them. I've gotten another couple of answers on another forum and 1 suggests that the control arm is bent and you just can't see it. Wouldn't that show up in the alignment? 1 more piece of info is probably not important but, When I took the car in for re balance and rotation Thursday they broke 1 center cap (they blamed it on them being brittle) So when I got it back the missing cap was on the right, when I got it back from the front end shop the missing cap is on the left. I don't know if he switched the tires or just the cap.

[Deepdoodoo]

Sorry about the above post. I'm new here and I responded to the wrong post.