I first noticed my car drifting left and/or right randomly after replacing my tires. I replaced the factory tires with the same Michelin's (~52k miles, currently at 60k miles). I've had alignment checked 4 times from 2 different shops, and lastly checked at the dealer. The dealer said they drove it on a "known straight road" and found no issues. "Known straight road" or not, I've been driving the same roads for years and never had this issue before. It's hard to believe that something would have failed at the same time that I got new tires, which is why I stated that I first noticed it after replacing my tires. The steering wheel feels tight without any play/slop, but while driving (especially at highway speeds) I have to constantly correct the wheel to keep from drifting left and/or right, randomly.

Has anyone had issues with their steering rack? Is there a module that controls the amount of assist that is applied to the steering rack that could be failing?

I hate Easter-Egging, but I'm at the point that I want to just start replacing parts until something fixes it.

My car is a '12 F Sport SE

Thoughts?

 

So how much toe-in you have on front and rear? Have you tried to increase tyre inflation?

 

Have you had your alignment checked recently? My Toyota Tundra was recently doing the same thing, and I thought it was completely fine until I put it on an alignment rack.

 

Since you noticed after the tires were replaced, check to see if all the new tires were properly balanced. Usually unbalanced tires cause vibration but might be worth checking. Are all the tires the same size, double check the side wall numbers.

 

Toe is set to "0" on both sides (verified from the printout I received from my most recent alignment at Lexus of Mobile). Increasing the tire pressure makes the issue much worse. I typically run around 40 psi on my car and have been since I got it in '12. Now, I run 32 psi to lessen the issue.


Yes, I had it checked 4 times before going to Lexus of Mobile and they did an alignment, too. The issue still remains.


Yes, they were properly balanced and there is no vibration. All of the tires are the same, bought brand new.



It seems like the car is trying to correct/assist in turning with changing road conditions. The steering wheel is always tight, and rock solid. As far as the electric power assist, are there sensors on the rack that aid with turning or is there a module that controls the assist? If there is nothing external for electric power steering assist, I'll just buy a new steering rack.

 

You probably have tire belt pull, and I am surprised none of the mechanics raised this issue.

It occurs because the internal belts in the tire may make the car pull to the left or right. It is diagnosed and sometimes cured by rotating the tires. Sometimes it may be cured by flipping the tire on the wheel so the opposite side faces out ( if your tire design allows it). Sometimes you have to replace the tires. It is not a balance issue. It is not a problem with your car as it began with the new tires. It is probably a problem with your new tires.

See this from Tire Rack http://www.tirerack.com/tires/tirete....jsp?techid=12

 

Zero is very strange Toe-in, because it will cause just this drifting you're describing. There should always be some toe-in to prevent that, but Lexus maintenance should know correct values. Is there another Lexus dealer around to ask another opinion?

 

I found these alignment spec ranges on another thread

Spec Range
Front Camber -1.0 to 0.5
Front Caster 5.1 to 6.6
Front Toe 0.00 to 0.20

It was unclear if Lexus of Mobile did all 4 alignments or if you had had someone else look at it. If they had done all of them it is time for someone else to do it. Your alignment can have all the numbers in the green zone on the computer printout and your car may still drive like a POS. They have to tweak it for your concerns.

 

Attached is the printout from Lexus. I see adjustments to front and rear toe, but not camber.

What's a good value for the toe (so that I can specifically ask for it).

 

You have zero total toe-in on the rear axle, that could be the problem here. If specs say 0.00"-0.20", it could be set to 0.05" like on the front axle.