Negative Camber in the Rear and Expensive Tires

[lolachampcar]

mnx,

Just be prepared for slightly less straight line stability when it comes to "hunting" or following grooving on the highway. One thing toe in on the rear of a car does is make it very stable in a straight line. Going to near zero toe in for me reduced my power consumption, increased my range and added slightly (but noticeably) to the tendency of the car to wander or hunt when on the interstate.

 

[rogbmw]

mnx,

Just be prepared for slightly less straight line stability when it comes to "hunting" or following grooving on the highway. One thing toe in on the rear of a car does is make it very stable in a straight line. Going to near zero toe in for me reduced my power consumption, increased my range and added slightly (but noticeably) to the tendency of the car to wander or hunt when on the interstate.

Did you leave it at near zero toe?

 

[zwede]

I've done some testing and found that for the rear wheels efficiency is the best anywhere between 0.15-0.40 dgr. Within that range I could not see any difference. I have it at 0.25 toe-in.

This is in contrast to the front that hates anything more than 0.15 dgr toe-in. I have the front set at zero. I have not noticed any impact on stability. It drives great on the highway. Zero front toe made it turn in much better at low speeds (more fun to drive).

 

[qwk]

mnx,

Just be prepared for slightly less straight line stability when it comes to "hunting" or following grooving on the highway. One thing toe in on the rear of a car does is make it very stable in a straight line. Going to near zero toe in for me reduced my power consumption, increased my range and added slightly (but noticeably) to the tendency of the car to wander or hunt when on the interstate.

How close to near zero toe are you on the rear? I just received my camber bolts, and will set the camber somewhere around -1.05 to -1.10 without changing the toe, to see how much of the inside wear goes away. My car is very stable in a straight line, and does not hunt at any speed, so I want to leave the rear toe alone if I can.

- - - Updated - - -

I've done some testing and found that for the rear wheels efficiency is the best anywhere between 0.15-0.40 dgr. Within that range I could not see any difference. I have it at 0.25 toe-in.

Is this total toe-in or per side?

- - - Updated - - -

I asked for an alignment the other day during my annual and my rear camber was set to -2.1 and -2.4 (with -2.4 being out of spec). I guess since my car was wearing 19's they left it as is....

What was your rear camber at?

Just read back a few pages and noticed your settings. Yikes, that setup has to shred tires very quickly.

 

[lolachampcar]

I used 0.1 total toe in (just enough to not get toe out under hard acceleration exiting a corner). I did notice a difference in rolling resistance (coast down) and range when I went from 0.45 total to 0.1 total toe in on the rear of my car.

With the longer upper arms in the rear, I was able to get my car to -1.2 degrees of camber on all four wheels running reasonably low ride height (about air Low).

 

[zwede]

I've done some testing and found that for the rear wheels efficiency is the best anywhere between 0.15-0.40 dgr. Within that range I could not see any difference. I have it at 0.25 toe-in.

Is this total toe-in or per side?

That's total toe.

 

[ibxspeedracer]

Your Educated Opinions on my issue is much appreciated! Dropped off my P85 with air-suspension to have realigned and have the camber bolts installed at the Costa Mesa Tesla SC two days ago. Today I pick up the car and within minutes of getting on the freeway (@ 65mph+) I get the rear of the car lowering so low that I get total rubbing of the tires again the inside rear fenders while I'm driving on "low" suspension setting. Immediately slowed down, raised the setting to "standard" and returned to SC. The photos here show the car's rear parked in "standard" suspension setting at SC once I arrived. Also to note the passenger side rear is setting much lower than the driver's side! Also to keep in mind, I was driving for about 700 miles on these new set of rear tires (on new aftermarket 22x11 rims) of 285/30/22 size and had ZERO rubbing or any weirdness or handling or noise before SC did their realignment/camber-bolt-addition in the last 2 days. Faced with this PROBLEM after their alignment (spec sheet of my alignment by SC toady is here-in included) I was told that the air-suspension has adjusted to non-conforming wheels is the cause!!! Really!? How could that be!? Anyhow, I am thinking to have them put a set of OEM 19" wheels and tires back on and then align to "spec" with the camber bolts left in. Then I will reconsider whether or not use aftermarket (these or some other brand, if any) but for now I am really suspicious! I can't imagine how legitimate the SC's claim why the MS rear suspension has dropped soooooo much after the alignment and yet none of this was the case while I have had these aftermarket wheels/tires on the car for 700miles+ Any thoughts/comments appreciated! The car has only 5,400 miles on it and its no more than 3-4 months old.

 

[qwk]

That alignment is fubar'd. The rear tires are going to be eaten alive.

 

[ibxspeedracer]

That alignment is fubar'd. The rear tires are going to be eaten alive.

SC is putting on there 19" OEMs and realigning. I need to find someone down here in SoCal that knows how to set up the alignment on a MS that has an aftermarket package on it! I might be looking for something that doesn't exist but figured I still give it a shot!

 

[einTier]

Indeed. That rear alignment is so terribly wrong it's difficult to use the word wrong to describe it. Get it realigned immediately.

 

[zwede]

You're right to suspect that aftermarket wheels don't have any effect on the air suspension height adjustment. My thought is they damaged the travel sensors when they replaced the camber bolts so the car thinks the suspension is higher than it is (so it lowers it).

I'm disappointed the SC would even return the car to you with -3.0 camber. It's way out of spec and will make for bad handling.

Also, realignment won't help by itself. The SC needs to figure out why the car sits too low first.

 

[ibxspeedracer]

You're right to suspect that aftermarket wheels don't have any effect on the air suspension height adjustment. My thought is they damaged the travel sensors when they replaced the camber bolts so the car thinks the suspension is higher than it is (so it lowers it).

I'm disappointed the SC would even return the car to you with -3.0 camber. It's way out of spec and will make for bad handling.

Also, realignment won't help by itself. The SC needs to figure out why the car sits too low first.

Thats what I thought about the height adjustment too. Plus I had put 600-700 mikes on these rims/tires before I brought the car in for realignment/camber-bolts and I didn't have a single problem! Experiencing This catastrophic suspension failure immediately as I picked up the car from the Costa Mesa SC's re-alignment and camber-bolts addition is super suspicious...and that's just the tip of the iceberg as these alignment specs are seem to be majorly off too. Actually per their tech, these are the best spec's they had to dial in to get me the best alignment with these aftermarket rims/tires!!!

I'm hoping to get others of experience chime in here and maybe I'll be able to find a (better) guideline or solution.

For or now they are putting a 19" set on and re-aligning to the "spec" with the camber-bolts in! This way I would know if they return the car acceptable working order and spec. Then I can figure out the aftermarket rims/tires setup!

Anyone know a non-factory alignment shop here in SoCal that can deal with MS alignments!?

 

[jerry33]

Anyone know a non-factory alignment shop here in SoCal that can deal with MS alignments!?

There is really nothing "magic" about the MS suspension. Any reputable frame shop that deals with air suspension vehicles should be able to give you a good alignment.

 

[lolachampcar]

Some comments-
Having the proper test tools will allow one to calibrate the ride height and account for the new rims/tires.
Changes in upright location WRT the chassis caused by recalibrating ride height will change camber (your on a different point of the camber gain curve). This may also place the static upright position outside an acceptable range which does not allow for proper wheel geometry under full compression. It would be unreasonable to ask Tesla to (1) evaluate your particular combination for safety or (2) modify their ride height calibration procedures to put the upright in the correct neutral or static position if this causes the chassis ride height to be unacceptable. I'm not saying any of this is happening; I'm just pointing out the concerns.
Installing camber bolts will push the top of the rear tire outwards changing aftermarket tire to wheel well clearance.
A ride height calibration will spot a damaged or deranged sensor if one was damaged in the alignment process.
Tesla does not currently share software tools (like MB StarDiagnostics or Porsche PWIS) so only Tesla can address the ride height issue which means a manufacturer is providing tacit approval of a modification. Tesla is (and should be) reluctant to have anything to do with mods thus one of the rubs associated with proprietary one source service.

 

[Chris1howell]

A lot of time has past and I owe an update on link availability....

I am still working and making progress on the links, I thought it was going to be easy...send the files to a few people and in a few weeks have finished parts. BUT... Turns out the TESLA design is optimized for extrusion and is very very expensive to waterjet. Machining would be less overall but IF the design was optimized for CNC the end result would be far stronger and much less expensive...

As it stands now the part has been redesigned for CNC and a full analysis in Solid Works was performed against the original Tesla part. The final design is much stronger and a bit lighter. I am just waiting for machine time, this is a low volume part it has very low priority at the machine shop. To complicate things further TESLA will no longer sell the old links I will have to build up stock in swaps or everyone will have to upgrade to the P+ version with larger dampers, not a bad thing but more expensive for those of us with early builds...

 

[bradhs]

Hi Chris,

PM me the file and I'll see if I can get it done for you faster. I know of a fewachine shops in SD who might help us.

A lot of time has past and I owe an update on link availability....

I am still working and making progress on the links, I thought it was going to be easy...send the files to a few people and in a few weeks have finished parts. BUT... Turns out the TESLA design is optimized for extrusion and is very very expensive to waterjet. Machining would be less overall but IF the design was optimized for CNC the end result would be far stronger and much less expensive...

As it stands now the part has been redesigned for CNC and a full analysis in Solid Works was performed against the original Tesla part. The final design is much stronger and a bit lighter. I am just waiting for machine time, this is a low volume part it has very low priority at the machine shop. To complicate things further TESLA will no longer sell the old links I will have to build up stock in swaps or everyone will have to upgrade to the P+ version with larger dampers, not a bad thing but more expensive for those of us with early builds...

 

[Chris1howell]

Thanks for the offer Bradhs. The shop that has been helping me is owned by a member here and is a Roadster and Model S owner, so I would like to give him a chance first. His shop is very busy but I am sure he will come through.

 

[kishdude]

This excessive rear camber is a real issue. My car (P85) has 14,000 miles on it and I had the tires rotated for the first time at 4500 miles. At 9000 miles, during a service visit, Tesla told me that all the tires needed to be replaced due to inner edge wear. I had them replace all 4 tires ($2K). Now they are telling me the rears have to be replaced at only 5000 miles since they were installed because of inner edge wear (another $1K). This is bad. I don't drive aggressively at all. The SC told me that setting the ride height to low wears tires faster. Can't they just decrease the camber of the rear tires? Paying $1K every 5000 miles is worse than paying for gas.

 

[qwk]

This excessive rear camber is a real issue. My car (P85) has 14,000 miles on it and I had the tires rotated for the first time at 4500 miles. At 9000 miles, during a service visit, Tesla told me that all the tires needed to be replaced due to inner edge wear. I had them replace all 4 tires ($2K). Now they are telling me the rears have to be replaced at only 5000 miles since they were installed because of inner edge wear (another $1K). This is bad. I don't drive aggressively at all. The SC told me that setting the ride height to low wears tires faster. Can't they just decrease the camber of the rear tires? Paying $1K every 5000 miles is worse than paying for gas.

No matter what the SC says, this is not normal. Have them align the car, until this goes away. It may take some pressure from you.

 

[lolachampcar]

kishdude,

Reading through the whole thread will give you examples of different alignments and an appreciation for how toe can have a huge affect on tire wear. Luckily, toe is adjustable in the rear of MS. There are also Tesla's "Camber Bolts" the service center can install so that the resultant "bolt slop" can be used to bias for less negative camber.

Take heart that many have managed to have their cars adjusted to a more reasonable tire wear state. As qwk says, it can be done. There are also threads on Pilot Super Sports as a more cost effective tire alternative (assuming by your pricing that you are replacing PS2s).

and yes, excessive rear camber is a pain which is why I took steps to fix it when I collected my first car sixteen months ago.