Negative Camber in the Rear and Expensive Tires

[White]

Just got my car back from TiresUnlimited in San Jose, CA as my rear tires were wearing on the inside. The car has just over 9k miles and the alignment machine was a Hunter (with the latest Tesla MS specs).

Long story short the LEFT REAR tire was toed out at -0.23" and camber was at -2.0. degrees. The RIGHT REAR tire was toed out at -0.14" and camber was at -2.5. degrees. Guess that explains the wear, which was worst on the drivers side. Tesla has an issue with toe and camber that isn't being addressed by the service centers. I have been in and out of service about 8 times for different things...

:frown:

 

[Chipper]

Just got my car back from TiresUnlimited in San Jose, CA as my rear tires were wearing on the inside. The car has just over 9k miles and the alignment machine was a Hunter (with the latest Tesla MS specs).

Long story short the LEFT REAR tire was toed out at -0.23" and camber was at -2.0. degrees. The RIGHT REAR tire was toed out at -0.14" and camber was at -2.5. degrees. Guess that explains the wear, which was worst on the drivers side. Tesla has an issue with toe and camber that isn't being addressed by the service centers. I have been in and out of service about 8 times for different things...

:frown:

Truly a bummer! I feel sorry for you, White! I have to wonder how long it is going to take for them to figure out what it takes?

 

[lolachampcar]

White,
The camber numbers are what is to be expected with air on a lot of cars. The SC can adjust it a bit by using necked down bolts on the inside of the upper suspension arm (thus allowing them to pull the upper arm or pre-load it outwards before tightening the bolt down and clamping the bushing inner sleeve) but they will normally only do this if one side or both are out of spec.

The toe out thing has appeared way too many times to be a fluke. There was/is an issue with initial setting (highly unlikely) or perhaps toe link torque which is allowing cars to escape production with (or develop in the wild) toe out in the rear. This would fully explain why some people have reasonable wear in the rear while others are getting clobbered.

On an unrelated note, I was able to remove a pull in the front of my car buy matching caster. The alignment tech and I did not look close enough the first time we worked with the front (lowering had us setting front camber to the minimum allowed by the camber eccentric) and thus missed the eccentric on the trailing link. There is caster adjustment in the front if anyone finds they need it. My car now tracks true with 1.2 degrees of negative camber all the way around.

 

[gg_got_a_tesla]

This is all greek and latin to me but, spotted this on my service notes from a visit to the service center:

 

[tezco]

I had the same bolts replaced at my last service visit when I asked them to check the alignment, just to be proactive.

 

[lolachampcar]

gg,
Basically it is a smaller diameter bolt that allows more slop in the upper link system when the bolts are loose. The technician simply holds the assembly towards the "right" direction and tightens the bolt down. The extra slop allows the suspension to lock down in the "more right" direction which, in turn, helps reduce inside shoulder rear tire wear.

Hope this helps.

 

[gg_got_a_tesla]

Hope this helps.

Yes, I think so. Thanks

 

[lolachampcar]

A buddy of mine just sent me a note regarding Tesla and rear tire wear. I realized I've not summarized things lately for those new to MS so I've included the following bits of my response. This is only my opinion of course.

XYZ,


There are practical and necessary reasons for Tesla having so much baseline camber.


The baseline is referenced to "the lowest common denominator" which is a coil car. Those at stock ride height appear to need a minimum of about one degree of negative camber in the rear to pass federal stability control standards. There is one test in particular where the steering wheel is yanked from one side to the other, paused and then back. The idea is to induce a pendulum affect that you might see in an emergency maneuver. The way performance sedans have gotten by this is to have the rear "roll" onto more tire by running negative camber. If they take it out, they have to re-certify the car which they simply will not do. In addition, it is unclear if the car would pass with less rear negative camber.


Once you accept the baseline, you must make a decision about other models that can run lower. Do you change the suspension on those cars such that you maintain that same negative camber when the car is running lower or not.


Camber gain in the rear will cause negative camber to increase as the air suspension allows the car to lower. Using the same suspension on all cars is the cheaper way to deal with the issue but it means that air cars will have more camber at Standard ride then coils. This is exacerbated by low mode. Obviously, Tesla chose to have one standard set of suspension (even to the point of putting P+ LCAs on all production cars making the P+ package a damper valving and sway bar change).


In short, I understand what Tesla did and why they did it.


The only mistake I can see is blaming initial 4K tire life on owners. If it were me, I would have started from an "its my fault" position and examined the vehicle logs to see if the owner might be responsible. Once I determined the owner was driving normally, as I believe a lot of these owners were, I would have gone to school on the problem and learned that cars were getting into the wild with toe out in the rear. Tesla has now come to grips with that problem but they were slow in doing so. The penalty they paid is that EVERYONE became aware of the problem. I suspect tire wear is now much better and almost livable (as they intended when they made their design decisions) but Tesla has used up any good will on the subject by being too slow to respond on the toe out problem. People are less willing to accept it than they would have otherwise been.


You can try to work with Tesla but I doubt they have much room to wiggle. The only real meaningful possibility would be new upper arms that bring air cars to coil car camber levels when at standard ride height. That means producing an 18" extrusion die which has lead time and is very expensive. It also means carrying another part in inventory which they have been reluctant to do.


Camber bolts have been reported to get as much as 0.6 degrees of change. Longer arms could only be made to yield 1.0 or so if your minimum camber in the rear are coil spring levels so the bolts get you most of the way there. I think Tesla has found the right position for them even though it may not be the best overall position for owners.


I feel like I am caught in an Ayn Rand world where I do not contribute for fear of what those I am trying to help will do to me. The right solution would be to contract with an oversees CnC or Waterjet house to run 500 rear arms then buy or otherwise acquire 50 current arms with bushings. With this it would be possible to supply full drop in upper arms exchange for $300 and still make a reasonable profit. I would have no problem dropping the coin to make that happen in a heartbeat if we did not live in the world we have. Those that are concerned about tire wear get reasonable yet safe (as defined by coil cars) levels of camber.


but then that would be in a reasonable world and we do not live in one of those at the moment.


Hope the above helps.


Bill

 

[lolachampcar]

Someone asked were I landed on ride height.

 

[youlikeadajuice]

Well of course, you landed at an airport!

 

[linkster]

lola

Thank-you for this most comprehensive post (#308). Your highly detailed posts regarding this issue for more than a year have been invaluable to me and I am sure to many other members.. We currently have 23,000 miles on our S. Due to your expertise along with specific advice we will easily achieve 30,000 miles, but probably closer to 35,000 miles from our original 21 Conti's. The sharing of your knowledge has made our S safer IMO and will easily save us $1,000's over the life of our "S".

Thanks!

david

 

[GDH]

Is it possible to order a P85+ without the rear staggered wheels?

 

[andrewket]

Is it possible to order a P85+ without the rear staggered wheels?

Nope. Must accept the 21x9 wheels and 265/ PS2 tires.

 

[lolachampcar]

linkster,

Do you mind sharing exactly where you ended up with rear camber and toe?

 

[einTier]

Well, at 6k miles on my P85+, I've encountered this "issue" as well.

I've driven a lot of track cars and owned a lot of high performance automobiles, and the only tires I went through faster were a set of R-888's I used on a car that saw track duty almost as often as street duty. I still got 5k out of those. These same tires on my Porsche Cayman S used to go 10-12k with the occasional HPDE and autocross.

What I've never had is the extremely uneven tire wear. The outside edge wasn't even to the wear bars while the inside was corded. The extreme camber isn't necessary for performance (probably too extreme to help even on the track) and I want to go to something more manageable. Right now, Tesla tells me the camber is 2.0 and 2.1 on their rack. If I take it to another alignment shop, what I can expect them to get? I'm not used to factory cars having much flexibility in camber settings. Can I get it to 1.5 without aftermarket parts? 1.0? If not, what do I need to buy to get there? Ideally, I'd like 1.0-1.5 in the lowest ride setting.

 

[qwk]

Well, at 6k miles on my P85+, I've encountered this "issue" as well.

I've driven a lot of track cars and owned a lot of high performance automobiles, and the only tires I went through faster were a set of R-888's I used on a car that saw track duty almost as often as street duty. I still got 5k out of those. These same tires on my Porsche Cayman S used to go 10-12k with the occasional HPDE and autocross.

What I've never had is the extremely uneven tire wear. The outside edge wasn't even to the wear bars while the inside was corded. The extreme camber isn't necessary for performance (probably too extreme to help even on the track) and I want to go to something more manageable. Right now, Tesla tells me the camber is 2.0 and 2.1 on their rack. If I take it to another alignment shop, what I can expect them to get? I'm not used to factory cars having much flexibility in camber settings. Can I get it to 1.5 without aftermarket parts? 1.0? If not, what do I need to buy to get there? Ideally, I'd like 1.0-1.5 in the lowest ride setting.

I'm currently going through this with my car(although I have 19" wheels). The smaller camber bolts that Tesla uses give you 0.3 flexibility. Longer camber links would give you more, but would have to be custom pieces.

 

[lolachampcar]

0.210" longer center to center on the upper links will give you 1.0 less camber on air cars and put you right at the end of toe adjustment to achieve near zero toe in. I would suggest your super low life was a function of camber AND toe out in the rear. If you read through this complete thread and similar ones you will find many an example of people with documented tow out; too many for it to be a simple customer driven issue. Put differently, something about the production process and/or shipping drove the rear wheels being pointed outwards.

 

[qwk]

0.210" longer center to center on the upper links will give you 1.0 less camber on air cars and put you right at the end of toe adjustment to achieve near zero toe in. I would suggest your super low life was a function of camber AND toe out in the rear. If you read through this complete thread and similar ones you will find many an example of people with documented tow out; too many for it to be a simple customer driven issue. Put differently, something about the production process and/or shipping drove the rear wheels being pointed outwards.

I wonder how often the rear toe settings get knocked out of whack on these cars? My car was aligned about 8 months ago, and the rear still wears very fast on the inside edge only. Rear camber was unchanged at -1.36.

 

[bradhs]

If someone wants to sell their rear P85+ rims/tires please PM me. I can trade you with my P85+ front rims, which are standard P85 tires. This will get you a consistent front/rear setup.

 

[andrewket]

If someone wants to sell their rear P85+ rims/tires please PM me. I can trade you with my P85+ front rims, which are standard P85 tires. This will get you a consistent front/rear setup.

Where are you located?