Strange handling question

[Awall]

I am noticing something now that I didn't think the truck always did: when I go over a bump, it feels a bit more....skittish. Hard to really describe, but it almost feels like for a split second one or more wheels loses traction, but its incredibly brief...

For a second I thought maybe its just 4 wheel steer, but I expect that around turns to feel like the back end kicks out. This happens when going straight.

I haven't noticed it until now, and have had the truck a little more than 2 months. When I mentioned to my wife, she said she feels it as a passenger, but assumed that was just how it drove. Said sometimes it feels like it is skidding, but thought that was just how it drives (she isn't in it as often as her Model Y).

I normally drive sport, so expect it to be a little tighter and transmit a bit more of the road feel, but something just feels slightly off, like maybe the wheels aren't fully calibrated and bump makes it noticeable? I doubt its really skidding or bouncing in the air and free spinning or anything like that, way too heavy a vehicle.

I have a service appointment next week for this and the weird warbling sound around 35mph, but wanted to know if anyone else has noticed anything similar (maybe I can describe it better to service --I plan on taking them for a test drive regardless, but assume they will just say "in-spec").

Thanks,
Andy

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[Dazureus]

Yeah, I think there's a bit of a wheel hop over bumpy surfaces. The Beast uses the front motor more than the rear, so it's noticeable as harsh driving in the front. The AWD uses the rear motor more so that's probably what you're feeling.

 

[Awall]

Thanks Dazureus, this definitely describes what I am feeling better than I explained it. Given your occupation, I would put a pretty high degree of confidence in your understanding

I am assuming this also has some relation to the other thread discussing the beast's stiffness on accelerating into a bump except it is just manifesting itself differently in AWD? I'd definitely prefer the extra stiffness vs the floating feeling.

Do you think via software its something they will eventually tweak, or should I just adjust my driving expectation to include the wheel hop and move on?


Thanks again...

 

[Dazureus]

I'm not much into powertrain engineering, but I've heard from a few people that have experienced wheel hop during acceleration on rough surfaces, and experience it myself on the front end of my Beast. Combined with something I heard about the Beast using the front motor bias vs the AWD rear motor bias seems to match our experiences. I can hear/feel the difference in road materials (brick, crossing paint, etc) on my front wheels under even "light" acceleration.

I'm not sure if its something that can be fixed with software. In my '16 Model X, I would experience odd braking issues when the rear wheels would brake over a rough surface. It almost felt like ABS was kicking in and reducing the braking force. Although it's not the same situation with acceleration wheel hop, a software remedy would be along the same lines as traction control, and would probably feel like a loss of acceleration. I think because these motors put out so much torque at such low rpm, the wheel hop will be more pronounced vs. ICE powertrains. AT tire might also exacerbate the effect. Maybe it can be tweaked with the active dampening system, but I haven't looked across the boards at the Model S or X to see if those drivers have complained about something similar.

 

[AlmostHuman]

Check all your lug nuts. I had some coming off.

 

[Awall]

Thanks, checked the lug nuts and they were all tight. I did bring it to service, and as Dazerius mentioned they said it is driving and handling as expected.

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