[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?

 

[Occhis]

For future reference, Tirerack does carry MXM4 tires. In addition they offer a tire shaving service. So if only one tire is needed and the other tire on the same axle has an appreciable amount of wear, they can shave the new tire to match. Not sure of the cost but prob less than a new tire if the other tire has at least half the tread remaining.

 

[adayley]

How does the car drive when autopilot is not engaged?

Feels fine and normal.

 

[adayley]

Had four wheel alignment done. The front steer ahead was barely out. They adjusted it. I drove a bit on the freeway in auto pilot, about 4 miles. Didn't notice the weaving but it was a stretch of road with construction and such. I'll try a longer, clean stretch in the morning.

 

[adayley]

For future reference, Tirerack does carry MXM4 tires. In addition they offer a tire shaving service. So if only one tire is needed and the other tire on the same axle has an appreciable amount of wear, they can shave the new tire to match. Not sure of the cost but prob less than a new tire if the other tire has at least half the tread remaining.

I didn't check Tirerack and other online sources. I needed the tire replaced sooner than shipping could provide. I'll keep it in mind as it comes time to replace again. Thank you.

 

[Gauss Guzzler]

Autopilot keeps a running estimate of your tire's lateral stiffness so that it can provide more accurate steering inputs. It your new tires are significantly different than the old it might take a bit of driving for it to adapt. Though I'd be surprised if autopilot used *rear* tire stiffness to such a strong extent that you could feel the result.

Often new tires are a little squirmy for the first few hundred miles and maybe autopilot is just fighting/exacerbating that squirminess.

 

[minis2003]

how many miles on the old tires?
i wonder what the tire diameter difference of the old vs the new tires are??
about be enough to affect the driving dynamic

 

[adayley]

how many miles on the old tires?
i wonder what the tire diameter difference of the old vs the new tires are??
about be enough to affect the driving dynamic

Old tires had about 7,800 miles. So, a few millimeters difference? The new tires I think have deeper tread to begin with. I’m just guessing about effects of the difference.

 

[Gauss Guzzler]

How did you "end up needing to replace both rear tires" with 7800 miles? Is there more to this story that you're not sharing?

 

[minis2003]

i am guessing that the difference is about 2 - 5mm in diameter size ( deeper tread depth) that might be causing the issues, if you swap the new tires to the front the issue might go away, i would recommend replacing the other two tires

 

[adayley]

How did you "end up needing to replace both rear tires" with 7800 miles? Is there more to this story that you're not sharing?

Ah, you want the whole story. I’ll do it brief.

• The driver side, rear tire caused a warning on the screen for low pressure. I filled it.
• A week or so later, it was low again. I filled it.
• Then, after a time, low again. Time to start investigating.
• I found the head of a nail near the side wall but looked plugable.
• I pulled the 3-inch nail out. As I pulled it, I knew I was doomed because it was pointing in the direction of the sidewall.
• Plug did not work, wouldn’t go in.
• Put on the spare (modernspare.com)
• Looked around for the original tire. No one local had it in stock.
• Found the other tire in the recommended lists and in stock at Discount Tire.
• Asked Discount Tire to repair the tire, if possible.
• They found a second nail in the tire that I missed, at a repairable spot, but the hole I found could not be repaired.
• Since I was buying a replacement tire different from the originals, I bought two for a matching pair on the back.

And that’s how two, 3-inch nails in one tire forced me to buy two tires.

 

[Gauss Guzzler]

Ah, see - a story about two nails simultaneously wrecking one tire is way more interesting!

 

[adayley]

Had four wheel alignment done. The front steer ahead was barely out. They adjusted it. I drove a bit on the freeway in auto pilot, about 4 miles. Didn't notice the weaving but it was a stretch of road with construction and such. I'll try a longer, clean stretch in the morning.

This morning I triggered a camera recalibration and immediately took an 18 mile drive, mostly freeway. After the calibration completed, it seemed like the weaving during Autopilot was less. Soon I’ll take the same 60 mile drive that revealed the issue. Only then will I be confident the problem is solved, or not.

 

[BetaMan10]

I think the issue here is you are running a grand touring tire on the front and an ultra high performance tire in the rear. Sure they are both all season, but they are totally different animals. Personally if the tires are so new I would just save the MXM and run the AS4 on all 4 tires. You are just asking for trouble different wear rates significantly different tread design and different side wall stiffness. The AS4 is a much better performance tire than the MXM you might actually like how they ride when you have a full set of them anyway and either just try to sell the MXM or just use them down the line when you are able to get 2 more.

 

[jaybuz]

So, what was the verdict on whether or not the alignment fixed this issue? I changed two tires that had similar mileage on my Model 3, and I'm having the same problem with Autopilot...at speeds of 65mph or higher, it weaves back and forth within the lane. It gets worse at higher speeds. Mobile service recalibrated cameras and did other checks, but no improvement. The first time I replaced two tires, I had no problems.

 

[adayley]

So, what was the verdict on whether or not the alignment fixed this issue? I changed two tires that had similar mileage on my Model 3, and I'm having the same problem with Autopilot...at speeds of 65mph or higher, it weaves back and forth within the lane. It gets worse at higher speeds. Mobile service recalibrated cameras and did other checks, but no improvement. The first time I replaced two tires, I had no problems.

Alignment only needed one small adjustment so I don’t think it was the fix.

The problem has faded over time. The car no longer does the weaving at speed. The difference in tire models must have “evened out” with the initial wear.

 

[Khaiden]

So, what was the verdict on whether or not the alignment fixed this issue? I changed two tires that had similar mileage on my Model 3, and I'm having the same problem with Autopilot...at speeds of 65mph or higher, it weaves back and forth within the lane. It gets worse at higher speeds. Mobile service recalibrated cameras and did other checks, but no improvement. The first time I replaced two tires, I had no problems.

I have a similar problem. 2018 Tesla Model 3 LR rear wheel drive. Had Continental Extreme Contact DWS 06. Replaced 2 worn rear tires with same type. Front tires to the rear. The Model 3 drives now like a boat. Turning left or right gives you a weird feel in the spine. Autopilot does not drive straight, but has an oscillation. You can feel it at speeds above 60. All tire pressures are correct. Discount Tire did the installation.

Before tire change the car was rock solid on the road. Handled curvy roads extremely well. Now the car is completely wobbly in a curve. Really dangerous.

Any suggestions welcome.

 

[adayley]

Your issue sounds much more amplified than I experienced. I'd have a four wheel alignment done to see if that shows something. If that doesn't solve anything, maybe check the balance of all the tires. I don't have a good answer for you.

 

[jackmott]

This is a known thing when some tires are too different in diameter than others, the traction control system can't handle it and weird stuff like you have described happens.

 

[KenC]

I have a similar problem. 2018 Tesla Model 3 LR rear wheel drive. Had Continental Extreme Contact DWS 06. Replaced 2 worn rear tires with same type. Front tires to the rear. The Model 3 drives now like a boat. Turning left or right gives you a weird feel in the spine. Autopilot does not drive straight, but has an oscillation. You can feel it at speeds above 60. All tire pressures are correct. Discount Tire did the installation.

Before tire change the car was rock solid on the road. Handled curvy roads extremely well. Now the car is completely wobbly in a curve. Really dangerous.

Any suggestions welcome.

How much tread left on the older tires?

At worst, replace the older pair, and keep them as spares.

 

[Occhis]

I have a similar problem. 2018 Tesla Model 3 LR rear wheel drive. Had Continental Extreme Contact DWS 06. Replaced 2 worn rear tires with same type. Front tires to the rear. The Model 3 drives now like a boat. Turning left or right gives you a weird feel in the spine. Autopilot does not drive straight, but has an oscillation. You can feel it at speeds above 60. All tire pressures are correct. Discount Tire did the installation.

Before tire change the car was rock solid on the road. Handled curvy roads extremely well. Now the car is completely wobbly in a curve. Really dangerous.

Any suggestions welcome.

Sounds like you put the new tires up front. If that’s the case I would try rotating new ones to the rear.