[Two] New rear tires and now autopilot weaves

[adayley]

I had to replace the rear stock tires with a pair of Michelin Pilot Sport All Season 4 tires. Today I used Autopilot on a 60 mile round trip. The car was weaving slightly but noticeably in the freeway lanes. Just enough to be annoying. It didn’t do this before. It held a nice steady line in the lane.

Is a wheel alignment is needed? What else should I check or investigate?

 

[d1nownlee324]

I had to replace the rear stock tires with a pair of Michelin Pilot Sport All Season 4 tires. Today I used Autopilot on a 60 mile round trip. The car was weaving slightly but noticeably in the freeway lanes. Just enough to be annoying. It didn’t do this before. It held a nice steady line in the lane.

Is a wheel alignment is needed? What else should I check or investigate?

I am having this exact problem right now. What was your solution?

 

[adayley]

Solution (sort of):

I got a wheel alignment. The report showed just one adjustment 0.1 out of spec, which they corrected. Didn’t fix the problem.

Second step, I stopped worrying about it. The problem went away after a few weeks. If I had to drive every day on a long commute, I would have pursued a solution.

Sorry, I’m not not much help. I would have tried the tire rotation next. At present, the problem is gone, auto steer tracks straight and smooth, now.

 

[jackmott]

I am having this exact problem right now. What was your solution?

Already said it earlier in here, but when some tires are too different a diameter than others, the car can't handle it. Solution is make all the tires the same diameter. This *might* happen naturally just driving around for a while if they are close.

 

[adayley]

Already said it earlier in here, but when some tires are too different a diameter than others, the car can't handle it. Solution is make all the tires the same diameter. This *might* happen naturally just driving around for a while if they are close.

This makes technical sense. It makes little sense from a money and sustainability standpoint. I got in the situation because one tire needed to be replaced. Keeping all tires close to the same diameter would mean buying four tires even though three of them a fine. The car should be able to handle one new tire when only one needs to be replaced.

I’m wishing for your solution to be not needed, not that your solution is wrong. Hopefully improvements can change the need to keep similar diameter on all the tires.

 

[jackmott]

This makes technical sense. It makes little sense from a money and sustainability standpoint. I got in the situation because one tire needed to be replaced. Keeping all tires close to the same diameter would mean buying four tires even though three of them a fine. The car should be able to handle one new tire when only one needs to be replaced.

I’m wishing for your solution to be not needed, not that your solution is wrong. Hopefully improvements can change the need to keep similar diameter on all the tires.

Yes I agree it is a sad state of affairs and doesn't seem like it *needs* to be that way, but that it is a limitation of the software as currently programmed.

 

[sfgene]

Exactly my problem, I replaced 2 rear tires - they only had Michelin PILOTS and the front are original Michelin Primacy. The car became slightly squirrely. Its been 9 months but I just went to the tire store today to discuss this. I am having them find 4 new original Primacys for me. $1,200

PRIMACY MXM4 - SIZE: 235/45R18 -​

 

[chamshaw]

My m3LR failed warrant due one tyre at "0mm" tread. Our warrants allow for the tyres to wear 1.6mm before next annual warrant (costly but true). Replaced full set with Michelin Primacy 4s, aligned and away. Straight, quiet and more economical so far; down from 1.52 to 1.33 power usage... No point in trying to be cheap, guys...

 

[Lindenwood]

I might have missed it, but was tire pressure discussed?

 

[adayley]

I might have missed it, but was tire pressure discussed?

I didn’t discuss it. Maybe I mentioned it. Was not a factor for my issues. I check my pressure regularly and would have confirmed good pressures during my investigations.

It’s a good thought to check!

 

[Lindenwood]

I didn’t discuss it. Maybe I mentioned it. Was not a factor for my issues. I check my pressure regularly and would have confirmed good pressures during my investigations.

It’s a good thought to check!

I was actually thinking that different tire types can react differently to different pressures. For example, in previous vehicles I have had different tires take as much as +/- 5 PSI to achieve the same priority characteristics (comfort, efficiency, precision, etc). So, while they may be set at the desired pressure, they may need more if the sidewalls happen to be less stiff.

 

[aymelis]

Hi there, I am getting the same issue (swrving a lot) with Autopilot after I changed my back tires with Michelin Pilot Sport 4S last week.
Did you figure out how to fix this issue ? Did you have to do an alignment ? Thanks !

 

[adayley]

Hi there, I am getting the same issue (swrving a lot) with Autopilot after I changed my back tires with Michelin Pilot Sport 4S last week.
Did you figure out how to fix this issue ? Did you have to do an alignment ? Thanks !

Please read the thread. Answers to your questions are there.