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Negative Camber in the Rear and Expensive Tires

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> So we are discussing giving up handling for better tire wear on a high performance car? This reminds me of a discussion about hyper-miling in a Ferrari... [kaivball]

Stealth mode thread . . . plausible deniability . . . all that good stuff.
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From what I can gather, all this negative camber is designed to help the car pass the "wheel jerk" test in FMVSS 126. In the extreme, the trading wear for handling is accurate. However, I think a more apt description would be trading panic safety margin for wear as the negative camber will not show up on your radar on a day to day basis even during the most spirited driving.

The above said, it would be unwise for anyone to modify OEM suspension or reduce designed in safety margin without full confidence in what those changes do and how they affect each person's ability to control the car.
 
I had a good long conversation with Huibert Mees, head of chassis engineering for Tesla. It was incredibly nice of him to take time out of his day to call a customer. I do not think there is another car manufacturer on the planet that would have done that. Thank You!

Huibert confirmed the general understanding of the P+ field upgrade package saying it was a good balance between benefits and cost. I think someone posted that Elon said you get most of the benefits at an acceptable price which is consistent with Huibert's comments.

I did ask about large amounts of negative camber and he confirmed it was there to increase lateral stability in emergency maneuvers (like when you yank the wheel from side to side swerving to avoid something). I got the distinct impression that he felt the car should be left that way.
 
lolachampcar, do you have the before/after camber settings for your car? Apologies if I missed it, would be nice to have a summary of everything somewhere (perhaps the first post?).

The specs for the rear is -1.75 +- 0.35, even dialing it down to the lower end of that range (-1.4) would make a good difference while minimizing the effect on emergency stability.

Of course another option is to dial down camber in the front a similar amount - but this will very likely have the effect of reducing lateral grip as I'm sure that Tesla dialed in -0.75 +-0.35 in the front to maximize grip up there - most cars spec basically zero camber in the front. Perhaps this was done in an effort to maximize grip for the slightly narrow tires fitted stock compared to other performance sedans of similar weight.

For ultimate performance, most people look for at least -1.25 in the front and often up to -2.0 and a similar amount in the rear, though this definitely results in a car which is less stable under emergency maneuvers.
 
drees,
I am going from memory here but I believe I started out with something like -2.3 right and -1.9 left and had -1.3/-0.4 directly after installing the links. I took it down to the Dania service center because the front had -1.1/-0.4 leading me to believe there might be ride height imbalance leading to chassis tilt (thus the camber difference from left to right). My car turned out to be perfectly flat and Dania found the rear to be -1.2/-0.5 or now roughly the same as the front.

I did ask Huibert about the camber spread and he said something about assembling the rear suspension with play loaded to one side or the other which allows for a small amount of camber movement. I mentioned I was aware of the need to leave the bushing bolts loose until the car was in normal ride height so as not to put an angular preload on them. He confirmed that was necessary but pointed out that Tesla does it in a fixture when building the rear assembly while my doing it with the car on the ground and loaded causes all the play to be loaded to the maximum camber (which made sense). In short, you tighten one side's upper arm with the wheel loaded one way and load the other side the other way to achieve more balanced numbers across the car. I'm not too concerned about it and will wait until some other service to do that work.

Lastly, the large amounts of rear camber are purposefully designed into the rear of the car to INCREASE stability during emergency maneuvers. Huibert specifically mentioned BMW having done this for many years. Come to think of it, that rear suspension looks an awful lot like 7 series suspension :)
 
lolachampcar -

Awesome! That is amazing Huibert actually called you back as promised. So, do you think the retrofit would be worth it according to your discussion? I've partially customized my car and am very hesitant at selling it and getting a new one just for the P+ benefit. As you said before, hoping to keep the tires all the same and only upgrade the "rest" of the retrofit.

Thanks!

drees,
I am going from memory here but I believe I started out with something like -2.3 right and -1.9 left and had -1.3/-0.4 directly after installing the links. I took it down to the Dania service center because the front had -1.1/-0.4 leading me to believe there might be ride height imbalance leading to chassis tilt (thus the camber difference from left to right). My car turned out to be perfectly flat and Dania found the rear to be -1.2/-0.5 or now roughly the same as the front.

I did ask Huibert about the camber spread and he said something about assembling the rear suspension with play loaded to one side or the other which allows for a small amount of camber movement. I mentioned I was aware of the need to leave the bushing bolts loose until the car was in normal ride height so as not to put an angular preload on them. He confirmed that was necessary but pointed out that Tesla does it in a fixture when building the rear assembly while my doing it with the car on the ground and loaded causes all the play to be loaded to the maximum camber (which made sense). In short, you tighten one side's upper arm with the wheel loaded one way and load the other side the other way to achieve more balanced numbers across the car. I'm not too concerned about it and will wait until some other service to do that work.

Lastly, the large amounts of rear camber are purposefully designed into the rear of the car to INCREASE stability during emergency maneuvers. Huibert specifically mentioned BMW having done this for many years. Come to think of it, that rear suspension looks an awful lot like 7 series suspension :)
 
I am told by Tesla that there is a minor amount of camber adjustment in the bolt play. Basically, you loosen both bolts on the upper arm, preload the wheel towards your desired direction and tighten the bolts. Tesla uses a fixture with the uprights at ride height but not loaded so it is easy for them to do this. We have to lift the upright to ride height before tightening the bolts (to keep the rubber bushings from angular preload) which means the upright is loaded and thus harder to rotate.

This may be enough "adjustment" to get you where you want to be.
 
>there is a minor amount of camber adjustment in the bolt play. LCCar]

This just seems lame. An eccentric bolt would be far superior to relying simply on friction.

Btw, I gave a good look to my wheel positions yesterday when I found a nice paved level surface. All wheels have neg camber with a bit more on the rears. No difference between sides. So no surprise here as it just confirms what my benign tire wear already showed. Did not bring my carpenter's angle with me (makes note to self).
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Tires worn at 5500 miles? Will Tesla take care of this?

Sorry on Tapatalk and couldn't find a thread. Inside of both rears like this at 5500 miles. Sounds like rear camber was set wrong? Will Tesla take care of this? I paid for extended warranty nd ranger service. Car isn't drivable as is...
 

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Sorry on Tapatalk and couldn't find a thread. Inside of both rears like this at 5500 miles. Sounds like rear camber was set wrong? Will Tesla take care of this? I paid for extended warranty nd ranger service. Car isn't drivable as is...

You should get new tires prorated if I am not wrong . Since you are well into warranty period of tires...most of the tires come with 5 to 6 years with 30k to 90k miles warranty.