Cause of uneven tire wear
The outer edges of the front tires are worn out compared to the rest of the tire tread.
The alignment has been checked several times and everything is to spec. What other
possible reasons could cause this problem? The service manager is suggesting I
replace the struts/shocks to fix this issue.
The rear tires show even wear.
The vehicle was in a front end collision a year ago and that's when this problem started
happening. Car hit a tree smack in the middle of the grille. Everything forward of the
radiator was replaced.
On a related note, after the tires were rotated, now all 4 tires show the same worn outer
edge. However, one of the rear tires has turned into an "egg" shape such that when it
came time to rotate them again, with the "egg" shaped tire going to the front, the
resulting vibrations rendered the car undrivable. Any speed below 30 mph causes the
steering wheel to shimmy vigorously. Any speed over 30 mph and the whole vehicle
Again, the service tech blames a bad strut/shock for causing the tire to turn into an egg
and suggested I replace them.
Could a bad strut/shock be the cause of both these tire issues?
Thanks for any answers.
Have you checked into the rank-n-pinion? Mine was going bad and the shop installed brand new tires anyways, and I Wore through them in a month. If that is the problem, make sure they do another alignment after the rack is replaced.
Are the tires properly balanced? If so, how old are the struts and shocks? If the tires are worn on the outside or inside of the tire this is a chamber issue which can be caused by a weak, or broken spring. Worn struts/shocks will give you uneven wear called "Cupping". An egg shape tire to me would be the tire issue itself. If your over 100K, I'd replace the struts/shocks anyhow if you are keeping the vehicle for many years to come. Sounds like you need to correct the suspension and purchase new tires ASAP.
The tires are properly inflated and balanced on a regular basis. The struts/shocks are original. The vehicle currently has 77,000 miles on it. The "egg" tire developed the issue at around 40,000 miles. These are Michelin HydroEdge with 80,000 miles tread life. So even though the outer edges are worn, the center still has plenty of tread life left. I would like to know the cause of this problem before I purchase another set of tires. Thanks!
Looking for a Used Sienna in your area?
CarGurus has 26,267 nationwide Sienna listings starting at $1,950.
Search Toyota Sienna Questions
Toyota Sienna Experts