Will the Model S/X have a spare tire & if not, how is that ok?

[JST]

You could likely fit a "Space Saver" Spare!

My apologies if someone has already run this down, but back in my E90 M3 days we went through the same issue--no spare from the factory, no space saver option that was made for the car.

Enterprising folks realized that the space saver wheel from the X5, when equipped with the proper tire, would do the trick. It was large enough to clear the brakes on the M3. Since the bolt pattern and spacing is the same, that temporary steel wheel may work on the Model S, too. Of course, you'd need to find the right tire option.

http://www.m3post.com/forums/showthread.php?t=253769&highlight=spare

 

[Denarius]

I've had a flat every year or two for the last several years. I live in a new development and there is construction all around my home. Every time it's been a nail or a screw.

 

[jeff_adams]

Flat tires are much different these days. Most modern cars have tire pressure sensors so you know right away if you have a tire leaking issue.

 

[jerry33]

Flat tires are much different these days. Most modern cars have tire pressure sensors so you know right away if you have a tire leaking issue.

Had a flat last week on my trip and I noticed it only because I checked the pressures. TPMS didn't warn me at all. Here in Dallas I've had five flats in the last two years (not counting last week's).

 

[JST]

My apologies if someone has already run this down, but back in my E90 M3 days we went through the same issue--no spare from the factory, no space saver option that was made for the car.

Enterprising folks realized that the space saver wheel from the X5, when equipped with the proper tire, would do the trick. It was large enough to clear the brakes on the M3. Since the bolt pattern and spacing is the same, that temporary steel wheel may work on the Model S, too. Of course, you'd need to find the right tire option.

http://www.m3post.com/forums/showthread.php?t=253769&highlight=spare

To follow up on this, I did some digging. There are a variety of space saver kits for BMWs available now; the one for the X5 is too big, and the one for the 550 is too small, but it looks like the one that they offer for the X3 might do the trick for a Tesla. It's an 18" wheel, with a 145/80-18 temporary spare.

The stock (19 inch) Model S wheels have a diameter of 27.7 inches (the 21s are 27.8 inches). The 145/80-18 spare has a diameter of 27.1, a difference of 2 percent, which seems workable for temporary use.

As I noted above, bolt pattern is the same, but I don't know what the Tesla centerbore is, and whether this wheel would bolt up and clear the brakes or not. Might be worth a shot.

http://www.bimmerzone.com/BMW_Performance_Spare_Tire/BIM-SST-F25-KIT.html


Not sure what the load rating on that spare is, but the X3's curb weight is 4100 lbs, about 500 shy of the Model S.

 

[ksdprasad]

Flat tires are much different these days. Most modern cars have tire pressure sensors so you know right away if you have a tire leaking issue.

+1, few weeks back my carrera had a nail in the tire and constantly loosing air, my TPMS alerted me saying "you have x% of less air, possibly flat tire", so TPMS sure will pickup. i used my onboard compressor to fill the air to manage to get to tire shop.

 

[mknox]

Had a flat last week on my trip and I noticed it only because I checked the pressures. TPMS didn't warn me at all. Here in Dallas I've had five flats in the last two years (not counting last week's).

My former Cadillac CTS was great in this regard. The TPMS would throw a red warning light up, then I could go to the screen and call up each tire's pressure and see who the culprit was and how fast it was losing air. The screen updated pressure in real time so fast, that I used to use it with my air compressor when topping the tires up at home. No flat tire experiences with the Model S yet.

 

[Denarius]

They really need to update the TPMS to show current levels rather than just the alarm.

 

[jeff_adams]

They really need to update the TPMS to show current levels rather than just the alarm.

Yeah, for a car with this much tech, they should be able to do that

 

[UMD86]

They really need to update the TPMS to show current levels rather than just the alarm.

I was thinking about that before I blew out 2 of my 21's last night. In the Mercedes they show the actual tire pressure on each tire. I wish Tesla would incorporate that into their software.

 

[vgrinshpun]

I am planning to buy spare wheel/tire to have in my garage in case of emergency. Since my car has the Performance Plus package, I feel it is prudent thing to do as the 21" tires are not readily available and blown tire could mean a few days wait until replacement tire is available. The Performance Plus package, however, has bigger rear tires, so the question is whether one spare tire/wheel will do in this case.

I've sent the following e-mail to Tesla Motors to get their input; will post reply when they respond:

I have performance Plus Model S being built this week and delivered on July 24. The overall tire diameter for rear Performance Plus tires is approximately 0.55” larger than the overall diameter of the front tires.
I am planning to buy one extra wheel/tire set to serve as a spare in case of emergency. If I choose spare tire to be the same size as front tire (245/35R21) there could be a situation when the rear tire is damaged and replaced by the spare of the same size as front tire. Is it acceptable to run one 245/35R21 tire in the back while the other is 265/35R21? Please address the following in your response:

• Different overall diameter of the left and right rear tire as it relates to the different height between the roadway and left/right wheel axle.
• Different overall diameter of the left and right tire as it relates to the additional strain put on the rear differential
• Any other considerations not addressed above

In case it is OK to go with one size spare, what is better: to buy spare of the same size as front tires/wheels (245/35R21) or of the same size as rear tires/wheels (265/35R21)?
Front tire overall diameter: 2 x 0.35 x 245/25.4 + 21 = 27.75”
Rear tire overall diameter: 2 x 0.35 x 265/25.4 + 21 = 28.30”
28.30” – 27.75” = 0.55”

 

[jerry33]

I'd recommend against going with just one size spare. Might be okay for a couple of blocks at very low speed.

The overall diameter means very little. You need to compare the RPMs of the tire to get the percentage difference.

 

[vgrinshpun]

I'd recommend against going with just one size spare. Might be okay for a couple of blocks at very low speed.

The overall diameter means very little. You need to compare the RPMs of the tire to get the percentage difference.

The difference in RPMs IS the function of the difference in overall diameter. It seems to me that using different tires on front axles might be OK because there is no linkage between the right and left half axles and they rotate independently. The car would be level even with 0.55" difference in overall diameter because air suspension will compensate for this.

Using different size tires in the back could be more of a problem because of additional strain put on differential.

Ultimately I would be very interested in hearing what Tesla engineering has to say on this subject.

 

[jerry33]

The difference in RPMs IS the function of the difference in overall diameter.

This is correct for wooden wagon wheels or steel railroad wheels, but not for pneumatic tires. The RPM of radial tires is mainly fixed by the belts. In bias-ply tires it's mainly fixed by the inflation pressure. Use the RPM shown in the tire manufacturer's spec sheet. Do not use the overall diameter.

 

[vgrinshpun]

This is interesting information; was not aware of this.

I am still moderately skeptical that RPM is completely decoupled from the overall diameter - will check the numbers.:smile:

Thank you for the explanation!

 

[jerry33]

Well, it not completely decoupled. It's pretty obvious that a tire 15" in diameter will turn more than a tire 30" in diameter for a given distance But for use on the same axle you're trying to get within a couple of percent at most, and the C = pi x d formula for circumference won't be close enough for driveline safety. The overall diameter in the spec sheets is for clearance calculations.

 

[laalan]

Does the S come with a tire repair kit? If so where is it?

 

[kjl]

Does the S come with a tire repair kit? If so where is it?

No, but usually available at the Tesla Store (sold out right now).

http://shop.teslamotors.com/collections/model-s/products/tire-repair-kit-model-s

 

[laalan]

Thanks. I put a small compressor in the trunk after my first slow leak caused by a nail.

 

[4SUPER9]

I thought I would bump up this thread based on another thread regarding a similar discussion. Some people above had some interesting ideas: using a slightly smaller diameter tire on the front. Has anyone tried that yet? Any other creative solutions?
What about the run-flats? Is it true that they will reduce range, and if so, by how much?