Anyone have a good explanation why new tires would pull left when the old tires tracked straight? My dealer had aligned my front end and things were good. These new Revo's are going left pretty hard. It is not very noticeable around town, but on the interstate, it is pretty bad. I also have to get the tires back to the place where I bought them to get them rebalanced. They shimmy pretty bad at 65 mph.

 

This is just a guess based on my experience but I had the same kind of thing happen a few years ago...

Alignment seemed bad... pulled to the left... I just fought it with the steering wheel. Over time the tires seemed to wear in such that I didn't have to fight it any more.

50,000 miles later when I put new tires on, all of a sudden, wow! This is really pulling bad!

If the alignment was fine tuned to drive straight with tires that were warn in when fighting the pull, when you put new tires on, the alignment seems off.

I know it sounds wierd, but that's what happened to me.

 

If the truck drove straight after alignment it should drive straight with new tires. If you aligned the truck put new tires on at the same time I would suspect you don't have enough caster on the right wheel. I had this same problem. I found that shops don't really like to adjust the caster as it requires taking the ball joint loose, removal of a shim bushing (possibly with air chisel) and then reset the entire thing.

The first thing I would do would be cross the front tires left to right and move the rears to the front to see if the problem clears. IF it clears or moves to pull right you can suspect tires. If it continues to pull left look at the alignement. I had my 7.3 Ex aligned with new tires and the shop insisted the front end was within spec, but the truck pulled right. I took it to a specialty shop and the front end WAS within spec but that is why it was pulling. More caster could be added to the right wheel (and still be within spec) to stop the pull. The shop ordered the "factory design shim from NAPA) and then reset the caster. Now it drives like on rails. Hope this helps. Jim