No spare, no run flat, no running on 3 wheels. Just a can of goo!

No spare, no run flat, no running on 3 wheels. Just a can of goo!

As delivery time approaches I worry about the lack of a full sized spare and a place to put it (since it can't fit in the frunk); or, even a doughnut that could fit in the frunk. The car with air suspension can't crawl to the nearest repair center on 3 wheels. I really don't like or want run flats, so that's not upsetting to me; but, relying on a can of tire sealant is extremely worrisome. What does that goo do to the tire, wheel and pressure monitoring system (I assume the Model S has one)? In case of a blow out does Tesla just want us to deal with the night stalkers until an approved tow truck arrives?

Robert22 | September 8, 2012

No worries Tomas. Didn't want those shy a few organs to think they were immunocompromised ;) OTOH it's one less thing to get pressed against your spine when flooring the accelerator!

EdG | September 8, 2012

Unless someone finds out otherwise, I'm not putting too much hope in the idea that the suspension will be able to be programmed to lift the one offending tire off the ground.

Granted that I've always changed tires on cars with typical spring suspensions, but the amount I've had to jack up the car was far more than the difference between "low" and "high" points that the Model S suspension can reach. I've neither seen any specs nor rumors that might suggest the active suspension would even be close to capable of lifting a tire fully off the ground.

jerry3 | September 8, 2012


I'm just going by other cars that have had adjustable height suspension. It's not just the suspension travel between the highest and lowest point. There is also the angle of the car when the suspension lowers the car. What happens in cars that I've had:

1. You raise the suspension to the highest point.

2. You put a jack stand(s) under the car at either one or two points depending on the design.

3. You lower the suspension to it's lowest point.

4. As all four corners go to the lowest point, the body leans to one side and two of the tires lift off the ground. There's really no programming involved other than the raising and lowering that's already there. Some of the lifting is provided by the suspension lowering and some of the lifting is provided by the tilting of the car.

Will the Model S behave this way? I don't know, but there's no technical reason why it shouldn't.

walla2 | September 8, 2012

I came up with a great idea:

A expandable rim. It's small enough to fit in the frunk, the tread is floppy, and the tube is prefilled. , you crank it to 19 inches, The tube gets compressed between the denser rubber of the tread and the pressure increases. You now have a 19" spare to get you 50 miles on at lower speeds.

Then I found this 1929 expandable rim patent.

With today's technology, this could be a real solution if someone wanted to make it and use it on all cars not just Tesla to reduce spare tire volume.

Timo | September 9, 2012

For those that say tonsils and adenoids and appendix are vital to the immune system and those that say those provide no function at all, you are both wrong. They are not vital, nor do they have no function at all.

Evolution is clever in a way to "invent" new uses to old structures. That's how we have hands and not flippers and why big toe doesn't do same thing as thumbs even that it has exactly same bones. If those remnants of the old have any function at all they stay.

Carmine | September 9, 2012

Walla2 & BYT, your finds are awesome.
Timo, please read my post from yesterday more carefully. I pretty sure that's what I said & in the real world I actually get paid for saying things like that! Enough with Immunology.
Again, does any Teslaholic know if a doughnut will fit under the rear floor panel where the jump seat would go; and, if so, can it be secured in that location or in the frunk?

Timo | September 9, 2012

I think that rear floor panel is too shallow for Model S tires. They are quite wide tires. (and Carmine, if you said what I said then I can't but agree with you :-) Not actually arguing, just pointing out that in world of biology things are rarely just black or white, so going at either extremes is equally stupid).

dborn | September 9, 2012

It seems to me that the solution is a redesign of the liner in the frunk. This really should not be such a big deal. It is not metal stamping dies we are looking at here, just a mold on which the liner material can be shaped which should be easily doable and quickly, with CAD and rapid prototyping equipment. Could probably be done and dusted within a week.
I do know that our local Tesla rep in Sydney did tell me that he is planning on keeping a full size spare in stock for loan to those who want it prior to embarking on a long road trip. Doesn't solve the day to day nails etc. we (Mark E and I) encounter regularly in this town.
I too am medical, but not an allergist. Carmine is 100% correct. I was being simplistic in my last post, but will leave it there.

sergiyz | September 10, 2012

As far as long trips vs short trips go.
I got stranded a couple of times within 10 miles of my home.
If not for the spare tyre, it would have been way more inconvenient for us to get home. It was a 15mins job vs taw on a flatbed with us taking a cab home, plus living with one car for a couple of days while waiting for a new tyre.
I'd prefer a full size spare as well, so I could deal with fixing/replacing the bad one as time permits, especially the 21" ones that are not exactly a commodity.

Volker.Berlin | September 10, 2012

I think Ron and Barbara explained Jack Mode: It freezes the air suspension to avoid automatic leveling, which it would normally do. When fixed on a tow track, automatic leveling could work against the equipment that holds the car in place, potentially becoming loose or damaging the car. If have yet to hear about lift-a-leg (TM) functionality in the Model S, the "Jack Mode" it is not.

Volker.Berlin | September 10, 2012

As mentioned earlier in this thread, an in-depth discussion of this topic, including the role of air suspension in this context, can be found here:

mrspaghetti | September 10, 2012

I've used fix-a-flat in tires many times and the shop was able to repair them afterward with no problem. If tire shop guys are telling you they can't repair a tire after it's had fix-a-flat in it, they're either misinformed or trying to get you to buy a new tire unnecessarily.

Carmine | September 10, 2012

tesla.mrspaghet-I like your response. AlexK mentioned that earlier in this thread with the use of the Slime product. Does it make a difference which brand of fix-a-flat is used? I still worry about messing up the tire pressure monitoring system.

Christy | September 12, 2012

I noticed that there is a Model S tire repair kit offered in the Tesla Shop. Does anyone know what it is or does?

stephen.kamichik | September 12, 2012

It looks like a compressor to inflate your tires and it obviously plugs into the 12 volt outlet of your car.

ReeceWeb | September 12, 2012

Yes, it is clearly a compressor that plugs into the 12v outlet.

However, it is called a "Tire Repair Kit, so perhaps it also includes a Tesla-approved can of Fix-a-flat? If it is just a compressor, it should probably be called a "Tire Inflator Kit".

Carmine | September 17, 2012

I realize that a spare would increase weight and decrease range but shouldn't Tesla at least offer a doughnut spare (TESLA ARE YOU LISTENING!) and a place to securely stow it for those of us willing to pay. I don't have range anxiety but I do have blow out HIGH anxiety. I'll take the can of fix a flat too with a compressor for the nail or the screw as long as it doesn't mess up the wheel and pressure monitoring system.
Spoke to some friends who have performance tires and they felt that because of the softer "rubber" there cars were susceptible to more flats. True or not?

poolman1237 | September 17, 2012

I have a question: Does the 21" wheel & tire have the same circumference as the 19" wheel & tire?

Carmine | September 17, 2012


Yes, same diameter/circumference but the 21" is a a little wider.

Brian H | September 17, 2012

The circumference has to be the same, or the speedometer, odometer, gearing, and so on all have to be adjusted. The walls of the tires are exactly as much shorter as the rims are wider. So to speak.

poolman1237 | September 18, 2012

Question: Since both the 21" and the 19" have the same circumference, which would be weigh less if I wanted to carry one on long distance trips as a spare?

jerry3 | September 18, 2012

The 19". The 21" wheel has more metal because both the rim diameter and width are wider.

Timo | September 18, 2012

I'm not so sure about that. Aluminum rims are light, rubber is surprisingly heavy and you reduce twice the amount of rubber compared to added aluminum when you go from 19 to 21. My bet would have been other way around. Whatever the reality, difference is not very big.

Vawlkus | September 19, 2012

I can state for a fact that 18" rims are noticeably heavier than 18" rubber tires. As the size increases, I'd be willing to bet the rims are still gonna be heavier.

Timo | September 19, 2012

Heavier than tires alone, of course, but you don't add whole rim in this size increase, only two inches of rim poles, and remove two inches of tire twice (two inches from both walls of the tire).

Timo | September 19, 2012

hmm...add a bit circumference increase to tire base to that rim...about 9.5 inches. That's a bit more than I thought it would be. Lesson to learn, always calculate before using intuition. 9.5 inch long block of aluminum in tire that is as wide as Model S tires are is not a small piece.

Vawlkus | September 19, 2012

The middle of the pie always has more meat to it than the crust ;)

poolman1237 | September 19, 2012

Ok, for a spare, carry a 19" wheel & tire, a small bottle jack,and the proper socket size in the trunk. For long distance trips away from home.

rwang | September 21, 2012

I've asked about this. You can get a 5th 19" wheel for a spare at $275+cost of a new tire.