19" and 21" Tire Wear (informal) Survey

[Owner]

Doesn't this require you to "jack up the front wheels"?

To get a very accurate toe-in measurement jack up front wheels and scribe a true running line on the face of the tire. Place the gauge in front of the tires and align the pointers with the scribe lines. Then move the gauge to the rear of the tires and align the fixed end with the scribe line. On the other end loosen the thumb screws and move the slider until the pointer aligns with the other scribe line. Now read the exact toe-in on the scale. Quick, easy, & accurate. A reminder… The scribed line can be anywhere on the tire face.

The alignment figures you display DO NOT equal the inside shoulder on your tires. I'm with Zwede on this one; go to an independent tire shop and have them give you their print out for the alignment as the car is now (before it goes back to the SC). It looks a whole lot like toe out to me.



If people have a concern over the accuracy of the SC's alignment specs and these concerns are costing $1000 per 8500 miles, I would recommend the following-
Toe-In Gauge

For less than $150 delivered to your door, you and a bud can check toe with a standard ruler in less than three minutes! There is no guessing, speculation or arguing.
This will not tell you thrust angle but then that is not as critical as total toe.

 

[zwede]

I like the string method. Easy and accurate. I posted it here: How to measure toe yourself (with pictures)

 

[lolachampcar]

The pro plates require measuring front and rear with a tape. That is problematic when working with such small variance over such a large distance. Tape droop or obstruction in the bottom of the car can be a problem.

I've used toe bars without the need to scribe lines. It is hard to describe, but here is a whack at how to do it-

Good bars have a slide adjustable pointer both on the long portion (side to side) of the bar and the little pointer piece that actually references on the rim.
So there are three dimensions which I will call the Long Arm being the side to side portion, the Medium Arm being the one that goes up from the ground in a vertical fashion and the Short Nub that is a small pointer that goes from the vertical arm to actually touch the rim.

Adjust the Long arm distance such that the Short Nubs are just a tad bit wider (1/4" ish) than the rear of the outer edge of the rim.
Adjust the Short Nub so that it is about half way up the rim when the toe bar is inserted behind the wheel and the Medium Arm is vertical. Getting the Short Nub height close to the center line of the rim is good enough for what we are doing. Most people can get it within a 1/4" of the CL so any error here is really small. Most of the time the Long Arm will slide far enough under the tire to allow the Medium Arm to reach full vertical. Even if it does not because the rim and tire diameter does not allow for the Long Arm to slip far enough under the tire (between the tire radius and the ground) for the Medium Arm to reach vertical, the resulting Medium Arm angle is the same front and rear so it is not a problem.

Once you do the top two adjustments, have a bud hold the Short Nub on the rear of the rim on one side of the car while you use a machinist's rule or a set of calipers (my favorite as you can zero digital calipers on the rear measurement then directly read the front measurement) then slide the toe bar around to the front of the tire and do the exact same thing. If the front number is larger than the rear number you have toe in (and, of course, vise versa). A couple of practice runs once you get the bar set up for your car and you can make the measurement in fifteen seconds This is why I was so surprised that Tesla did not make toe bars a fixture at SCs such that every car could be checked before being delivered as part of the PDI. It would have been an $80 investment per SC and taken their people mere seconds to confirm rear toe. I guess that would have been too simple and too obvious along with admitting defeat (or at least the need to check before delivery).

I'll measure rim outer diameter and post the geometry for converting the measure numerical toe to angular toe for direct comparison with the results from the SC's alignment machines.

- - - Updated - - -

OK, stepping back to high school geometry (which was a while back for me so take all results with a grain of salt)-

Tan angle = Opposite over Adjacent
Opposite is the measured toe
Adjacent is the wheel radius which is 11.25" for my 21s and 10.125" for my wife's 19s.
Using a target toe in of 0.2 degrees (for a total toe in of 0.4 degrees) I come up with 0.040" measured for the 21s and 0.035" measured for the 19s.

To come up with your own angles, use-
Arc Tan (Measured Distance / Radius of your wheels (19s or 21s)) If you have an IPhone, use calculator and turn the phone sideways to get the "engineering" version of the calculator and thus access to trig functions. Use the second key to access Arc Tan.

I was shooting for 0.1 degree per side for a total of 0.2 degrees of total toe in on the rear of the car. These numbers are soooooo small that (1) you better be using a caliper and (2) you need to be good at reading very small numbers with those calipers A machinist's rule is simply not up to the task.

 

[jerry33]

The deluxe toe-in plates seem easier to use - and then you don't have to worry about scribing a line in your tire or wondering if the ribs are lined up accurately, either.

Would love to hear the pros/cons of each.

Looks good. Ordered one.

 

[linkster]

Decided to crawl under and check today - P85+ 8600 miles, PS2 worn through to the cord.

I drive like a geezer. The car spends 99% of its time at standard height. Alighment set/checked by the Dallas Service Center at 900 miles and 5000 miles.

This is just nuts.

LR today -

View attachment 53048

Alignment 10/13 "everything ok"

View attachment 53045

Alighment 2/14 5k miles "everything ok.

Checked again when in for service 4/14 @ 6400 miles - "5/32 rear"

View attachment 53046

This is just crazy wear on a very expensive tire.

1. I COMPLETLY disagree with the first 1/2 your last statement
2. And, I respectively disagree with the handful of subsequent posts
3. All the P85+ cars have the "new style" high-durometer bushed UL's (neither design has a material effect on tire longevity)
4. No Model S just goes out of alignment (under normal driving or barring a related component failure)
5. Tesla has already stated that 10K is the approximate life span of the 265's
6. I submit that if Bolt HF M12x1.75-70 [10.9] 9.8 SHNK p/n 2007078-01-A was available/installed when you initially took possession of your most incredible P85+, you would have reached the Tesla stated 10K mark
7. The two alignment docs that you posted are the best I have ever seen and the SC tech should be HIGHLY commended (especially for taking the extra effort required to "push" the rear camber to its minimum factory limit) for such a precision alignment
8. Nobody seems to mention the extended tire life they are achieving on their fronts of P85+ for a truly balanced conversation
9. I am still simply perplexed and dismayed that intelligent Model S owners COMPLETELY disregard Tesla's warning/statement/disclaimer regarding 21’s, opt for them anyway (they do look SCHWEEET), then whine about the additional care/maintance/replacement costs
10. If P85+ owners don't want the hassle and expense of staggards, then sell them and procure 19's.

Tesla Motors website:
"21-inch wheels with low-profile performance tires wear faster...."

 

[zwede]

Linkster: You post would have been correct if the tires had been worn out. That's not what the picture showed. Cords showing on the sidewall of the tires is not a wear issue, but an alignment (toe) issue. Yet his alignment printouts from the SC show correct toe. There's a problem here. The tires could not have worn the way they did if the alignment had truly been like the printout says.

 

[linkster]

We will then have to agree to disagree then.......


1. So, nobody believes the SC's alignments anymore, E V E R R? (yes, they had some growing pains, along with many areas of this young, most incredible company)
2. It is very generous and gracious of you and lola to provide "step-by-step" highly-detailed instructions on performing toe measurements in one's own garage. However, I would submit to you that very few S owners have the tools, desire, knowledge, time, skills, and patience to perform such a precision measurement nor adjustment task

 

[zwede]

That's ok, we can disagree. I try to not be this guy.

 

[redi]

Yep, we will agree to disagree on this one. The tread across my tires are, for all practical purposes, great. The inside upper shoulder area is worn and through to the cord.

21" wheels are equipped with low-profile performance tires... (check)
Provide less protection from and are consequently more likely to suffer damage... (check)
from uneven road surfaces, debris, curbs, and other common obstacles... (check)
Damage to wheels or tires is not covered under warranty (check)

Tesla Motors website:
"...21-inch wheels with low-profile performance tires wear faster...

and reduce battery range... For best results follow maintenance including tire rotation" (wha??)

They might have said "8-10K is all you can expect" and nobody would be a bit surprised, just like no surprises on the other caveats. They don't say that or anything close to that.

Curious to see what what sort of tire life 210 upper links will result in if they ever emerge to general availability. Looking at my tread left I would have expected 20K if that's where the wear would have occured.

 

[redi]

Linkster: You post would have been correct if the tires had been worn out. That's not what the picture showed. Cords showing on the sidewall of the tires is not a wear issue, but an alignment (toe) issue. Yet his alignment printouts from the SC show correct toe. There's a problem here. The tires could not have worn the way they did if the alignment had truly been like the printout says.

Thanks to the suggestions of zwede and lola I spent the last couple of hours over at our local track/performance suspension shop. As usual the guys were very helpful and interested in understanding the problem and potential fixes.

They indicated that it was apparent from the way the tires were wearing (even before the alignment check) there was a toe-out problem.

What they found (taking zwede's word for the trig that each mm of difference corresponds to ~0.1 degrees with 21" wheels )

Left - 3/32" toe out (.0939 in, 2.381 mm) or over .2 degrees toe out
Right - 9/32" toe out (.2813 in, 7.143 mm) or over .7 degrees toe out

Total toe = 3/8" toe out (.375 in, 9.525 mm) or about .95 degrees toe out.

Yes that is toe out not in.

It is hard to understand how 2500 miles ago the toe in was a hair over .1 degree compared to the readings on what it is today - the toe in my case (if both the 5k and 8.5k readings are accurate) has moved 1cm in 2500 miles.

 

[zwede]

Did you set it to spec (0.30-0.50 toe-in) yet? Once I did I was amazed at how nice the car drove. I mean, it drove nice before, but after it felt like I was driving on glass.

I bet you meant total toe out of 0.95 degrees, not 9.5 degrees.

 

[redi]

Did you set it to spec (0.30-0.50 toe-in) yet? Once I did I was amazed at how nice the car drove. I mean, it drove nice before, but after it felt like I was driving on glass.

I bet you meant total toe out of 0.95 degrees, not 9.5 degrees.

No I did not want them to touch it just yet. I only wanted them to check where it was before talking to the SC. I have a problem with 8k miles until cords showing on the inside shoulder. I'll have them take another look next week after the SC investigates.

And I fixed my decimal point. Thanks, zwede.

The shop did have a few ideas they are marinating on. The shop spends all their time on track and performance suspension and was frankly wondering why this (a seemingly simple and easy-to-fix issue) had not been resolved by the owner community or Tesla at this point.

They suggested considering some fabbing up some inexpensive shims like some of the other performance cars do to keep the toe-in settings locked-in. Once the right shim was in place the toe-in wouldn't (couldn't) move like others Tesla owners are reporting it does.

example http://forums.corvetteforum.com/att...15-camber-plates-hardbar-vs-pfadt-hardbar.jpg

They also suggested that it should be fairly simple to fab up adjustable upper and toe links - examples for another make:

But they seemed to think that this tire wear is not a camber problem, in fact the sub 2 degree neg camber would not make much difference in the end, it was primarily a toe-out problem.

 

[lolachampcar]

redi,
OMG now that is toe out. That must have been a real hoot to try to accelerate out of a corner

The links are all super easy to fabricate; liability is the issue. Also, I think you are not giving locking eccentrics enough credit. Many manufacturers use them and they work well even on lower a-arms (Ferrari) where the stresses are much higher than toe links. Not sure what is going on for other owners but I have NEVER had an issue with toe moving even the slightest amount and I was playing with different toe settings on my car for some time (which means I had it on and off the alignment rack multiple times over a six month period with two different MS').

 

[redi]

redi,
OMG now that is toe out. That must have been a real hoot to try to accelerate out of a corner

The links are all super easy to fabricate; liability is the issue. Also, I think you are not giving locking eccentrics enough credit. Many manufacturers use them and they work well even on lower a-arms (Ferrari) where the stresses are much higher than toe links. Not sure what is going on for other owners but I have NEVER had an issue with toe moving even the slightest amount and I was playing with different toe settings on my car for some time (which means I had it on and off the alignment rack multiple times over a six month period with two different MS').

Thanks, I really appreciate all you do on this subject.

I remain puzzled, and cannot explain how toe has switched from slightly in (exactly to spec) to way out (1 cm worth) in such a short period of time. Something or someone isn't doing its job.

 

[zwede]

Interesting thing would be if you take it back to the SC and they measure toe within spec. That's what I'm suspecting: Their machine is out of calibration.

 

[Dave EV]

Interesting thing would be if you take it back to the SC and they measure toe within spec. That's what I'm suspecting: Their machine is out of calibration.

+1 - My money is on the fact that their alignment rack is out of calibration. There's no way they measure it multiple times over 8600 miles, find it in spec (0.2* toe in) each time, and then you end up with wear like this.

This isn't the first time someone someone has had this happen, either.

 

[redi]

I sprung for a set of these toe plates and I think I have a pretty good test case.

The deluxe ones are dead easy to use and seem to be very positive and have no slop when positioned on the wheel. The deluxe model has little magnets to hold the ends of the steel tapes (provided), and little pointers with a reference line on the other. It makes measuring total toe a very easy 3-minute affair and you can tension both tapes at the same time, one in either hand.

I indeed have significant toe-out as my recent independent alignment check confirmed.

The distance between tapes on these plates is 21.5" and the OD of a 265/35-21 tire is 28.3" so I am assuming there is some conversion factor to compensate for tire size when using the plates as if the toe was measured from the tire surface.

 

[zwede]

With the distance between tapes being 21.5" you'll be right at 1 mm = 0.1 degrees:

21.5" = 546 mm

1/546 = 0.001832

atan of 0.001832 = 0.105 degrees

 

[Dave EV]

I sprung for a set of these toe plates and I think I have a pretty good test case.

With the distance between tapes being 21.5" you'll be right at 1 mm = 0.1 degrees:
atan of 0.001832 = 0.105 degrees

Nice - so 2 mm should be a good target to aim for in the rear - 0.21* which would put it right in spec and 1 mm would be great for the front.

Now take those plates to the service center and show them how far out their alignment rack is!

 

[jerry33]

But they seemed to think that this tire wear is not a camber problem, in fact the sub 2 degree neg camber would not make much difference in the end, it was primarily a toe-out problem.

They are correct. Camber is not considered to be a tire-wearing angle, however, it amplifies any other alignment problem. If you look closely at the tires, you'll see one kind of wear across the tread and at the inner shoulder you'll see that very extreme angular wear (where the cords are showing). What happens (from my observations) is that the slight wear across the tread is from straight ahead driving. The angular wear is from cornering. The wheel on the outside of the turn lifts up and the tread tries to fold under which causes that angular wear. This wouldn't happen if there wasn't toe-out.