19" and 21" Tire Wear (informal) Survey

[cfOH]

Here are the official Tesla Model S alignment specs, as provided to me by a Tesla technician today while I was at my local alignment shop:

http://craigfroehle.com/posted/ModelS_Alignment.pdf

For the record, my alignment with just 411 miles on the car (P+ VIN 16073) was as follows:

Pretty far from ideal, especially that thrust angle. At least my camber isn't as extreme as some have been.

BTW, my tech, who has probably forgotten more about alignments and chassis setup than most of us will ever know (he used to crew on F1 and various other pro/mfr. racing teams) was aghast at the 21" wheels Tesla forces P+ owners to buy. And I have to agree with him...it certainly doesn't help performance.

 

[LuckyLuke]

Excellent piece of information, thank you.

So what would your alignment tech consider "better" for P+ instead of the Tesla 21" set? 20" ? 19" staggered? Something else?

 

[dsm363]

Pretty far from ideal, especially that thrust angle. At least my camber isn't as extreme as some have been.

BTW, my tech, who has probably forgotten more about alignments and chassis setup than most of us will ever know (he used to crew on F1 and various other pro/mfr. racing teams) was aghast at the 21" wheels Tesla forces P+ owners to buy. And I have to agree with him...it certainly doesn't help performance.

What is the issue with the P85+ wheels (do you mean rims or tires) Tesla picked?

 

[Johan]

What is the issue with the P85+ wheels (do you mean rims or tires) Tesla picked?

Value for money is poor.

 

[cfOH]

Bigger wheels = more unsprung weight to deal with and less sidewall to cope with surface irregularities. His belief is that no car needs more than 19" wheels because that's the largest needed to clear the brakes. Anything larger is sacrificing function for aesthetics.

 

[jerry33]

Bigger wheels = more unsprung weight to deal with and less sidewall to cope with surface irregularities. His belief is that no car needs more than 19" wheels because that's the largest needed to clear the brakes. Anything larger is sacrificing function for aesthetics.

Sounds as if he knows what he's talking about.

 

[yobigd20]

no car needs more than 19" wheels because that's the largest needed to clear the brakes. Anything larger is sacrificing function for aesthetics.

^^^^ this.

21" tires/wheels serve no practical purpose other than to show off and say "hey, look at me and how much money I have to spend on new wheels every 5k miles!" end of story.

All kidding aside (sort of, lol) , I find the 21" tires/wheels to be a safety concern. I wouldn't feel comfortable (ignoring the 5star crash safety ratings) driving my family around in a vehicle where the tires were susceptible to blowouts and the possibility of causing a major accident when hitting a pothole or any other road hazard at highway speeds.

I wish this information could be communicated better to customers when configuring the car. I think a lot of people get into the mindset of "I won't settle for anything less than the best of the best" and check every little icon and option available without giving any thought to the potential danger of 21" tire blowouts (of which there have been dozens of incidents already recorded on these forums, fortunately none resulting in an accident that I'm aware of).

My advice; if your ordering now, don't get the 21s, and if you already have them, get rid of them ASAP!

IMO I can think of only 2 valid reasons to order the 21s:

1 - the car is used primarily at car shows and on display. Aesthetics only.

2 - the car is primarily used for racing at tracks and not frequently used on street roads.

Outside of that , again IMHO but I think my points are valid, due to the higher chance of blowouts, clearly I've said it's a safety concern but also consider this: not only is it a concern to the passengers in your vehicle , but also to others on the road!! This car is a tank and will obliterate anything it hits so for that reason alone I think the it would be best to have 19s instead of 21s. Why subject yourself to increasing the chance of harming others just for "looks?" Ok I admit I might be blowing this out of proportion but that's how I feel about it at least...

 

[lolachampcar]

and for a counterbalance to the above.....

Race car guys only know tuning cars with sidewall flex. Just listen to all the goings on in F1 regarding tires and the associated spring rate and damping with different constructions. These things are out of the car engineers control and thus of primary concern. I faced the same thing on the ChampCars. Half of the 1.25" of front ground clearance was consumed by tire sidewall flex leaving only .625" of travel for me to control with springs and dampers. I would have preferred stiffer sidewalls and thus more of the chassis movement under my control. Sure, sidewall flex does move the wheel/brake/upright mass more to the sprung category but there is a price to be paid for this.

Moving on to street cars, the whole sprung to unsprung argument goes out the window when you are talking a 4600lbs of total car mass. The car will accelerate better with less wheel mass but ride quality and ability of the wheels to follow the road will hardly be affected by five pounds per corner either way.

I agree with YBD that there is no absolute reason to have 21s versus 19s and that 21s will be more problematic. I've commented in the past about weighting the risks of blow outs from inner shoulder wear against loss of over steer margin from running less camber. Where I differ from YBD is that I prefer the response of MS without the side wall flex of 19s. This preference has nothing to do with at the limit handling. I'm talking day to day steering response and feedback from the road. It is personal preference and my preference is for the smallest time constant in car control. I also like the way they look so, yes, I am shallow

 

[FlasherZ]

IMO I can think of only 2 valid reasons to order the 21s:

1 - the car is used primarily at car shows and on display. Aesthetics only.
2 - the car is primarily used for racing at tracks and not frequently used on street roads.

For me, it was two things (one of which really doesn't apply anymore):

1. The 19" 5-spoke wheels are simply not my thing - I won't call them "ugly", but I just don't like them. The new cyclone wheels are still asymmetric 5-spoke wheels in that there are 5 groups of 2 "fan blades". I really love the look of the symmetrical turbofan wheel style that the 21" has. Now that the 19" Rials are available, I'm getting those. Don't ruin the resale value of my 21" wheels with this thread yet...

2. When I configured (Sig), we didn't save anything by going to the 19" wheels on the P models. Value for the money and all that.

Other than the fast wear on the inside shoulder, I've already had 2 tire incidents during last winter, one from a curb rub that created a small cut in the sidewall and one from a pothole. Those things turn into brittle, 21" rocks in the winter and I will go broke replacing tires in the cold if I don't change.

 

[nleggatt]

Can I get the tires rotated anywhere I want? Special instructions?

 

[gnelson]

My P85+ drives much better than the P85 loaner I drove with 19 in wheels. Although I like the asthetics, I got 21 in wheels because that is what comes with a P85+. I also understand the potential problems with 21 in wheels, but I am not going to do what Yobigd20 suggests. I don't need winter tires in Houston! I don't want to sacrifice handling and ride quality and drivability. I am happy with my P85+, and others can be happy with their 19 in wheels.

 

[jerry33]

Can I get the tires rotated anywhere I want? Special instructions?

Yes, just pick a place that is comfortable with 21" wheels (assuming that's what you have).

Wheel nut torque is 125 ft. lbs. I'd check both the torque and the tire pressure the next morning.

 

[lolachampcar]

jerry,
WoW on that 125 ft-lb number.... I wonder what went wrong on the design desk/factory to drive that number?

 

[AlMc]

jerry,
WoW on that 125 ft-lb number.... I wonder what went wrong on the design desk/factory to drive that number?

Guess I won't be pulling those off on my own.

 

[gene]

Guess I won't be pulling those off on my own.

Huh? 125 pounds (actually I think it is 130) is nothing. A 1/2 inch drive breaker bar is 18 to 24 inches long. You only have to lean 60 to 80 pounds of your body weight on to the bar to loosen or tighten. Easy even for an old 57 year old gieser like me.

I use two floor jacks and only rotate front to back on one side (I'm old school). I have 19's. I just swapped my front and rears at 9,000 miles. There was about 20% less tread on my rear tires, I think I'll get near 20k miles. I have standard suspension and I am pleased that my tires are wearing perfectly even across the width of the tread. With standard suspension the rear camber is near neutral resulting in excellent tire wear.

 

[gtimbers]

I bit the bullet and went for new wheels and tires. I stayed with the standard 19" x 8 size using a TSW Forged alloy rim. It weighs about 21 pounds instead of the stocker's 30 pounds. I also tried the new Michelin Sport A/S 3. It is alleged to have summer tire performance with all season wet and wear characteristics. The wear number is 500! After 200 miles, I can report that they handle like a wild animal. All of my steering drift is gone and the adhesion is nuts. They ride (even on 8 lb lighter wheels) about as smooth as the Goodyears. They do make a groove whine at certain speeds, but they are still really new. I plan to rotate them at 500 miles or so left to right and then again front to rear so that the leading edges of the outer blocks get to experience all positions. I think that will take care of the noise and I can then return to regular rotation intervals. I watched them do the install (took the old sensors off and moved them over). When it came to final torquing time they called for this guy named King K. He looks kinda familiar to me - big guy, really hairy, snorts a lot - anyway, he just jumps up and down on the torque wrench until it clicks. Seems straight forward enough. At this time (200 miles) the power consumption is a little higher than my long term average. It was really high at first but is coming down steadily. Hopefully it will reach about the same number as the Goodyears. It is a lot stickier tire though, but I hope the wheel weight reduction helps.

BTW my car is Silver, not white. It is really hard to photograph.

 

[jerry33]

jerry,
WoW on that 125 ft-lb number.... I wonder what went wrong on the design desk/factory to drive that number?

Nothing went wrong. A heavy high performance car requires that kind of torque. The Corvette takes 130 ft.lbs. IIRC.

The nuts have big shoulders on them. The idea is that they won't pull through under maximum g-force turns (this isn't even remotely fun--even on a race track).

 

[wycolo]

> The nuts have big shoulders on them. The idea is that they won't pull through under maximum g-force turns [jerry33]

Yes, beware the 'pull through'!!

 

[Only Trons]

S85 (non performance) Vin XXX8404
Delivered late April 2013
19” Goodyear Eagle RSA
Air Suspension
Regen on Standard
292 Wh/mi lifetime average
Moderate driving style; some highway (mostly 55 – 60 mph) but mostly local roads. Did run the Richmond International Raceway about 20 laps or so as part of a Tesla event.
3,362 miles; not rotated yet
Current depth readings provided as xx/32; measured from inside out for each tire.

RR 9+ 9+ 9+ 9+
LR 9+ 9+ 9+ 9+
RF 9+ 9+ 9+ 9+
LF 9+ 9+ 9+ 9+

By “9+”, I mean the measurements were over 9. Most came in around 9.6. I used Central Tools 3S401 Digital Tire Tread Depth Gage for measurements (in decimal format which I converted to xx/32). I measured each tire tread twice (in the same location) to ensure I didn't skew the measurement.

I check tire pressure weekly after car has been sitting for several hours; I have topped up the pressure once or twice by one or two pounds to maintain the recommended 45 psi.

Visual inspection does not reveal anything unusual at this time.

 

[texex91]

Is it just me, or why isn't this becoming a bigger deal--and more importantly, why isn't Tesla addressing it!

There is NO way that any tire should be replaced (I'll take 21" as example) after 5K-7.5K miles. I've owned 3 911's and the lowest mileage I had to change those high performance tires was around 15K. Why are we putting up with this?

I'm putting my order on hold for now, as this shows me Tesla is not paying attention to these issues.

And BTW the answer isn't "put on 19' they are better". If they cannot support 21" tires, then don't sell them on your vehicles.

With the other issues I've seen thus far (which I can ignore most) with S, I'm not going to buy tires ever 5K miles when there is no need.