Shuttering / juddering in reverse low speed fully angled wheel - MY'25 AT 20's

[newlucidguy]

So does that sound normal or do you guys suspect a mechanical issue. Leased MY'25 AT 20" wheels. When I back out of my driveway and cut the wheels all the way and dive at a very slow speed, my front tires seem to judder / skip and I get a strong vibration in the steering wheel. Almost feels like the tires are skipping on the ground somehow. Anyone else have this / sound familiar? What might cause this? Stock tires - might they be rubbing on the tire cowel?

 

[borski]

So does that sound normal or do you guys suspect a mechanical issue. Leased MY'25 AT 20" wheels. When I back out of my driveway and cut the wheels all the way and dive at a very slow speed, my front tires seem to judder / skip and I get a strong vibration in the steering wheel. Almost feels like the tires are skipping on the ground somehow. Anyone else have this / sound familiar? What might cause this? Stock tires - might they be rubbing on the tire cowel?

Call service. Might be a balance issue or might be something else, but it’s definitely not normal.

 

[Johnny]

I also have a MY'25 AT with 20" wheels and I have not had that happen to me, though I've only had the car since Nov. Closest I've come to your driving situation is making tight U-turns in two-lane roads but that was in Drive not Reverse and I didn't have your experience. Suggest you call the SC if this persists.

 

[newlucidguy]

Actually it might be "normal". I'm finding references to the Ackerman effect. And I am running the summer tires which are quite grippy.

 

[rfc805]

You are describing the result of incomplete Ackerman effect at low speeds and full lock.

I haven't experienced it in the Air, but the full lock turning is pretty extreme so I've also never had to try it.

 

[newlucidguy]

You are describing the result of incomplete Ackerman effect at low speeds and full lock.

I haven't experienced it in the Air, but the full lock turning is pretty extreme so I've also never had to try it.

Yeah after some research, I think so. Case closed!

 

[Neurio]

I've had it happen rarely, though oddly enough it happened on my way to work this morning as I backed out of my garage. Given that it was never constant, I have ignored it thus far. TIL about the Ackerman effect.

 

[borski]

I have never heard of this! TIL!

 

[rfc805]

The simple solution is usually just unwind the wheel like, 1-2 degrees from lock.

I only know it from having daily driven some sports cars that specifically do not have Ackerman geometry by intent, and it's quite a violent thing near full lock at 1-2mph.

 

[new owner]

Agree with rfc805
Unwind a few degrees
I’ve experienced this backing out of garage
With black ice or cold wet conditions
Feels like slipping
22 AGT

 

[coma24]

Yeah after some research, I think so. Case closed!

I have it happen on a regular basis at full lock when pulling into my garage ('22 GT). It hasn't felt like anything back is happening, mechanically. That's with 21's on the Pirelli summer tires.