NHTSA Tire issue reported on Tesla 21 Inch tires

[tomas]

I think Tesla's engineers made the decision to use the same geometry for the air cars as for the coil cars. Put differently, I think they chose not to pair the air springs with a different upper link to maintain the same camber. I would guess that this was done to limit the number of part numbers and ease the production process as rear power assemblies could be built without regard for suspension spring choice.

Might be getting somewhere, though I confess to being a suspension novice. Are you saying a certain amount of non-flat camber is somewhat unavoidable with setup of air suspension and upper link, particularly when suspension automagically shifts from "normal" to "low". Thus creating a proclivity for some abnormal wear. Which, by itself, if camber is not otherwise off, would result in slightly less life than expected with the 21" wheels and rubber. But, combine that with any other alignment issue - particularly toe out - and then you've got the 4-5k problem???

TM should 1) better inspect alignment on each delivery starting now, and 2) offer a free alignment check to all air suspension cars, because it sounds as if some people have had bad enough alignment to burn through 19s. None of which negates a bit of owner responsibility to inspect tires once in a while and follow up on any alignment clues, rather than just let the tires wear out and then get angry.

Reminds me, I had a weird problem with BMW 545 and run-flats that developed astonishingly bad road noise starting at 7,500 miles. Not a one time issue, because I went through 3 sets in the time I owned the car. BMW never called me in, but knew about the problem, and paid for the first replacement... but told me I was on my own thereafter.

 

[strider]

2. The Model S appears to be very picky about rear toe. If it's spot-on, then tire life appears to be fine. If it's not spot-on, tire life suffers--sometimes dramatically. Does anyone actually have the spot-on specs?

I would love this data if we have it. lolachampcar? Our car is going in for its annual in December and I would love to ask that Tesla align to our ideal and show me the report.

We just replaced our Conti's at 13,640 miles w/ cord showing on the rears. If I had rotated a little earlier I think I could have gotten another 3k out of them as the fronts still had some inside rubber. I thought about going ahead and rotating them and having the wife drive w/ cord showing on the inside of the (now) fronts but thought better of it and replaced all 4. I'm going to rotate every 3k on this set (last set I rotated at 3k, 8.5k, and was about to rotate at 13.5k when I noticed the cords). It takes less than an hour in my garage and my 2 year old loves helping out (mostly by hiding the lug nuts ) so it's time well spent.

On a related note the shop who installed my tires (tirerack affliated shop) does mostly BMW work and he said he installs aftermarket kits that decrease the amount of negative rear camber on tons of his customers cars. So although I recall it being more difficult to do on MS compared to a BMW maybe there's a market there. If I could double my tire life (there was tons of tread on the outside of the tires) then I would take the chance of decreasing lift-throttle oversteer as the tire savings would cover my insurance deductible But seriously, my wife has been through a Skip Barber school and knows not to lift if the rear end tries to come around.

 

[lolachampcar]

tomas,
Yes, my 535 ate rear run flats and they were not cheap. And yes, there are all kinds of camber eccentric solutions for BMW suspensions as they have been tire eaters for many a year.

strider,
I was concerned about a reduction in over steer margin at the beginning when first started making the upper links. We then took delivery of my wife's S85 and, low and behold, it had 1.2 degrees of negative camber which is exactly where the new upper links put my P85. Obviously minus 1.2 was sufficient to have the car pass stability control tests even with the higher ride height of the coil springs. If it is good enough for a high coil spring car then the exact same camber will only work better on the lower air sprung car.

....... as for me, I learned not to lift too much
99Shell Atlanta 1 - YouTube

WRT "ideal" alignment specs, I run as little rear toe (in) as I can and still have toe in at Low ride height. Jerry has mentioned several times that "camber is not a wear angle" but it will amplify any other issues with the suspension. I had this clearly in mind when choosing my rear toe settings.

If memory serves me, it was something like 0.1 degree of toe in at Standard ride height. I did run into a situation with the upper link installation on my P+ where we could not get one of the rear wheels to point out enough. I ended up running 0.4 degrees of toe in for a few days. My car was more stable driving down the highway but range suffered. We ended up having to loosen the sub-frame bolts which allowed the sub-frame to "snap" straight with the car. We tightened the sub-frame bolts and had equal amounts of toe adjustment on both sides. Once it was set to 0.1 degrees of toe in, my slight bit of pavement following returned on the highway and my range went back up.

 

[100thMonkey]

...I admire your focus but coming from the resource consuming side of sedan ownership it is unreasonable to expect a P85+ to have a small footprint. MS has a high performance sedan version and thus Tesla clearly need to identify it as a "high maintenance" version of the car for those customers not used to these things. ...

That's a good point and still it's going to be hard not to parse words on this. Tesla has been touting a "have your cake and eat it to" achievement with all versions of the S. Core to Tesla's branding, from the 60 all the way to the P+, is: "With no tailpipe to spew harmful emissions, Tesla vehicles liberate their owners from the petroleum-burning paradigm. They are the only cars to get more efficient from the moment they're first driven." UM, not if they are burning through the equivalent of 3-500 gallons of oil in tires a year! The P+ is branded as the ultimate expression of the Tesla line, not the dirty sport car version: "our vehicle dynamics team was able to achieve the rare outcome of simultaneously improving performance, comfort and efficiency." The P+ is just about the only car Tesla offers for loaner vehicles, the primary car offered for immediate purchase, with no caveats, it's offered as the ultimate "S". Tesla either needs to find a good fix for this or they need to make it abundantly clear that the P85+ is an exception to Tesla's core marketing principles, an ultra exotic, ultra finicky, petrol consuming vehicle. IMHO, finding a fix will be much easier than trying to find a way to smooth over the the apparent contradiction in core marketing principles. It's hard to imagine them being successful with tag lines like: "For those seeking race car like handling and willing to overlook the ultra expensive and resource intensive frequent tire replacement, we've created the P85+."

I agree that going to the NHTSA at this stage is overkill and potentially damaging to our beloved brand, but I'm also not surprised that people are fed up when they are stung with a several thousand dollar bill, and told this is normal, just a few months into ownership. I guess in the end, I want to know that if I go through the expense and hassle of selling the 21's and buying the 19" cyclones, that I'm not locked into a self destructing tire alignment issue. Ideally, Tesla would acknowledge this issue, find a fix and I'd put regular 21" tires on the rears and wait it out for someone to come out with an all season tire for them, that way, I'd have the best handling I can get with an all season tire and the elegance of the turbine 21's... that's the potential I thought I was buying with the P85+.

 

[lolachampcar]

I guess I've just been around this block too many times. My P85+ is soooooo much better than my old M5 in sooooo many ways. It even eats less tire as I have put camber where I want it to be. All of this is simply second nature to me and thus no surprise. I expect a car that does 0-60 in 4ish seconds to have really sticky tires. I also expect a car that weighs 4700lbs with that much torque to be hard on rear tires. There is no amount of Tesla marketing talk that can talk me out of these basic understandings. The P85+ is a superior car in every way to the M5 for me but it does not defy the laws of physics or those of common sense.

I believe Tesla can communicate this message and that the message is consistent with the company's core values. As a consumer, if I am uncomfortable with the excess of wearing out tires in 15K or so miles (my expectations based on very soft Pilots and proper rear alignment) I will choose the 19" S option and not the 21" P option. If I can live with the tire issue, then choosing the 21" P option is still much better for the planet then something like an M5.

Please pardon me for being a bit thick here but, apart from some exaggerated marketing, Tesla is really not doing anything wrong here. I think they are actually doing a lot right. I also think that, like the marketing hype around the financing ("how much your gas station time is worth"), Tesla will reign in the over zealous marketeers and strike the correct balance.

 

[100thMonkey]

First off Lolachampcars, I want to publicaly thank you for taking the time to tackle this issue. Of all the posters on this issue, I've learned the most from what you have said in various threads on this and very much respect your perspective and appreciate the extensive knowledge you bring and the time to detail you are paying this issue. you are benefiting us all!

I agree with your sentiment in many respects, it's more a matter of degree. Compared to what I'm seeing, on our P85+ with only 3.5 K miles on it, I wouldn't be nearly so nervous if the trajectory of wear was looking like it was leading to 15K mile life on the rears. the ride is so amazing I might even learn to live with it but instead I'm already down to 5-6 MM on the inside back tires and I've already been told 5-6K is normal and I can't live with that.

 

[lolachampcar]

100th,

I had to muck with my rear camber to have a chance of getting to 15K.

I could tell by looking at my P85 that it carried a lot of rear camber. You can tell by just looking at the car from the back that the rear wheels were leaning inward at the top. In my experience, if you can see it, it is at least two degrees. Sure enough it was -2.4 and I had about 20% wear on the inside shoulder after 800 miles; and that was with toe in. I also knew that, as the inside shoulder wears, it puts more pressure on the center and outside of the tire patch. This means that the wear rate is the greatest when the tire is brand new. I also knew from experience with BMWs and Ferraris that I would likely see 8K miles or so if I left things alone and could extend this to 12K if I rotated the tires across the rear of the car. Of course, this is expensive as it causes you to dismount and remount both rear tires. This is when I decided to fabricate the upper links and remove some of the camber. The first set cost me about $500 which I considered a bargain given the price of replacement Pilots and the value of not having to chase tire wear with rotations. Subsequent runs have gotten the price down.

 

[100thMonkey]

when you "corrected" the camber, did you notice a loss in performance? Initially I was under the impression that this was for performance sake but after following what you have posted over the last weeks, it appears it's not necessary to achieve the effect that the P85+ has become known for.

 

[joer00]

First off Lolachampcars, I want to publicaly thank you for taking the time to tackle this issue. Of all the posters on this issue, I've learned the most from what you have said in various threads on this and very much respect your perspective and appreciate the extensive knowledge you bring and the time to detail you are paying this issue. you are benefiting us all!

I agree with your sentiment in many respects, it's more a matter of degree. Compared to what I'm seeing, on our P85+ with only 3.5 K miles on it, I wouldn't be nearly so nervous if the trajectory of wear was looking like it was leading to 15K mile life on the rears. the ride is so amazing I might even learn to live with it but instead I'm already down to 5-6 MM on the inside back tires and I've already been told 5-6K is normal and I can't live with that.

I think we can take it now as a proven fact that if you have severe INSIDE tire wear, it is an alignment issue. I went to a special alignment shop on Friday to ask for their opinion. I showed them pictures of my replaced rear tires with the inside worn down to the thread. They immediately said "wrong toe". They took a quick look at the car and just BY EYE where telling me that the left side back tire has a strong toe. This was the tire which was replaced first and worn the most, so here we have it ! I was always disappointed by the cars handling and the tendency to "break out" on strong acceleration. Again, this was confirmed by the specialist as normal if you have strong asymmetrical toe, the car wants to break out to one side, driver usually overreacts which results in the terrible handling on strong acceleration. I am quite happy on one side, because this all can be fixed ! I have the car in service tomorrow and will report back once it is fixed if the drive is also stable.

The problem on Tela's side is their (at least in my case) ignorance of the problem ! After the FIRST occurrence of an extreme misalignment, all alarm clocks should have shouted at Tesla to have the service centers check the alignment BEFORE delivery. This could have avoided the "bad press" they have now !

Lolachampcar, do I understand you correct that with CORRECT alignment, we should get 15k out of a P ? Or does this count only for a P + ? I did not look, but is there any WIKI post with the aligment setup you are suggesting so people can simply copy that and go to either Tesla or their favorite alignment shop to get this done ?

 

[joesp85+]

If I could get 10K, I woudn't even complain. I am at 5300 miles and need a new set of tires. I am so scared to drive it hard because of the tire issue the last 1K miles, that i have averaged 295kw/hr. I might have bought 60kw...
I was one of the very first P85+ deliveries so there must be an issue with the early deliveries. I am going to service in one week, so lets see what happens. I am planning on insisting they replace all the 4 tires for free this time, and next time, i will have to decide whether to buy another set of 21's or maybe put some 20's aftermarket wheels.

For those looking for a better tire deal, Costco warranties the same Michelin PS2 tires--- fronts for 20K miles, and the rears for 10K miles(since I cannot rotate the rears). If the tires are worn again in another 5K miles, at least they will refund me 50% of the price for early wear.

 

[Denarius]

I just thought I'd add a data point here, as I have on the informal tire wear thread. I'm at 9k miles on my P85+ and am just starting to show some wear in my inside edge. I expect to get 12k+ miles out of my rears. I do plan on having my alignment checked to verify that my toe isn't moving out of alignment. I'd say 90% of my miles are freeway over 55, so my car has spent most of its time at the highest camber.

 

[lolachampcar]

joer,

MS' rear alignment is a simple thing to understand in that there is only one thing that is adjustable. All of the rear suspension links are fixed in length and only one, the toe link, has an eccentric adjustment bolt on the inside. This means that the alignment shop can only adjust rear toe.

WRT rear toe, there are two things to consider. The first is where the pair of rear wheels are pointing WRT the direction the car is traveling. This is called thrust angle and should be zero; that is, the set of rear wheels should be pointing the direction the car is traveling. The second consideration is how much toe in to use where toe in is the front of the rear tires pointing in towards each other just that little bit. As a rule of thumb, more toe in gives better straight line stability (less tendency to follow the grooves on the highway) and less range as you are scrubbing off energy by not having the tires pointed exactly straight. We all know where the extra energy goes now as it is used to wear your tires I have always approached rear toe on a performance street car to set as little as possible while making sure there is never toe out even under hard acceleration when the back of the car squats. Race cars uses toe out to help the car rotate on slow corners where the outside loaded rear wheel will tend to drive around the front wheels because it is pointed out (toe out). I can not imagine where this would ever be a good idea on a street car. So I ask the alignment tech to put as little as possible in the rear then we lower the car to Low and make sure it does not go positive. I'll then drive the car hard out of some slow corners and confirm that it does not do anything funny. I've found 0.1 degree of toe in works best for me.

In short, I go to the alignment shop with the goal of as little toe in as possible and check the car in Low after toe is set to make sure it does not go past zero. That number has worked out to be 0.1 degree for me.

Now, on to the stickier issue of camber. Tesla designed one set of suspension links for MS. They change the bushings for the P+ package but the castings and extrusions are the same from S to P through P+. Rear suspensions are designed such that camber increases as the rear of the car squats. This is called camber gain. Practically speaking, this means you have about -1.2 degrees of camber in a coil spring S with its high ride height and about -2.2 in a S, P or P+ with active air in Standard ride height. I say about because there are manufacturing tolerances that allow this number to vary from car to car. The numbers here are from my cars.

I expect my car to get at least 15K miles from the rear tires based on current wear numbers. I'm achieving these numbers because, at 100 miles, I replaced my upper links on the rear suspension with similar ones that were 0.210" longer. Pics of the links as they came out of the water jet are posted earlier in this thread. The longer length on the upper link "stood the rear tires up" basically removing a little over a degree of camber. My P+ now has about the same camber as my wife's coil spring S85 and the tires are wearing more evenly. The links were a one time PITA that keeps me from having to track wear so closely and rotate the tires across the back of the car. This approach is the only way I know of to change camber short of making changes to the lower a-arm (beefy part and bad idea).

I've always found that pictures help
Wheel Alignment Explained

 

[yobigd20]

I expect a car that does 0-60 in 4ish seconds to have really sticky tires. I also expect a car that weighs 4700lbs with that much torque to be hard on rear tires. There is no amount of Tesla marketing talk that can talk me out of these basic understandings. The P85+ is a superior car in every way to the M5 for me but it does not defy the laws of physics or those of common sense.

I believe Tesla can communicate this message and that the message is consistent with the company's core values. As a consumer, if I am uncomfortable with the excess of wearing out tires in 15K or so miles (my expectations based on very soft Pilots and proper rear alignment) I will choose the 19" S option and not the 21" P option. If I can live with the tire issue, then choosing the 21" P option is still much better for the planet then something like an M5.

Please pardon me for being a bit thick here but, apart from some exaggerated marketing, Tesla is really not doing anything wrong here. I think they are actually doing a lot right. I also think that, like the marketing hype around the financing ("how much your gas station time is worth"), Tesla will reign in the over zealous marketeers and strike the correct balance.

ditto. see my post #12.

The biggest problem here is not one of a "design flaw" , but rather "education of buyers".

 

[simplesolar]

Joer,

There is definitely something wrong with your alignment. I took my rear tires off at 8,500 miles and looked like there are about 2,000-3,000 miles left. the front looked brand new. I avg about 350kw/hr. Every new car I've gotten I've made sure to have the dealers check the alignment as they are always off.

 

[DIL]

so how will tesla "fix" this tire wear issue? will it be a version of lolachampcar's modifications to remove some camber, along with a pre-delivery alignment check? is it that simple, or am i missing something?

 

[dennis]

Late to this thread, but I thought I would post a photo of the 21" Conti's off my P85 with 6000 aggressive miles (400 wh/mi) and no tire rotation done. The fronts (on the left) show little wear and the rears (on the right) show a lot. And while there is a bit more wear on the inside of the rears, it is not excessive. My conclusions: 1) My alignment is OK and 2) with a rotation, these tires are good for another 4K-6K miles for a total of 10K-12K. Not great, but acceptable considering my driving style. It will be interesting to see what the PS2's look like at 6K miles now that I have upgraded to the P+ suspension/wheels/tires.

 

[FlasherZ]

EDIT: moved this post here, a better place for it.