Compact Space Saver Tire/Wheel Solution

[JST]

Thanks again for your efforts.

I understand you concern regarding using a compact tire on such a heavy car. However, obviously we would be carrying this tire to deal with a flat tire while on road trips and there is equally likihood of getting a flat in the rear as the front. Would you use this tire in the rear to slowly travel to the nearest tire repair location?

Thanks.

Larry

Well, what I would be most worried about mounting it in the rear is a) being very judicious with the power given the amount of torque you'd be sending through a 155 sized tire, and b) ending up promoting oversteer by having relatively less grip on the rear than on the front.

These concerns are probably not that big of a deal--I drove my M3 around for a day with a 135/70 compact spare on the back while I got the tire fixed, and it was fine. But where it might be an issue would be inclement weather/rain.

I am not worried about load capacity generally. The X5 wheel is designed to handle it, obvs, and the spare tire that I have is rated for more weight than the OEM wheel.

 

[4SUPER9]

JST,
Can you please summarize everything that would be needed to achieve what you did?
Thx

 

[JST]

JST,
Can you please summarize everything that would be needed to achieve what you did?
Thx

Sure, here you go, all in one place:


1 steel temporary spare wheel from a BMW X5, BMW part number 36-11-6-768-861. These are available from any BMW dealer, or online from www.getbmwparts.com. http://www.getbmwparts.com/parts/in...1-6-768-861&action=oePartSearch&siteid=214672
Cost: About $75.

1 155/80 18 compact spare tire. These are available new for about $300, but you can find them used for a lot less. Look for the compact spare tire assembly from a Mercury Marauder or Ford Escape Hybrid. I found a number of them for sale at Automotix.net, a wrecking yard aggregator, for about $150. Note—the automotix search engine makes it seem like all you are getting is a wheel, not a tire. I received both when I ordered, but another forum member called and could not get them to confirm the tire would come, too. YMMV, as they say.

2007 Ford Escape Wheel (Used VIN H 8th digit, Hybrid 18x4 compact spare aluminum) For Sale - Buy Ford OEM Parts

1 74.1 mm to 65 mm centering ring adapter (basically just a piece of plastic with those diameters, respectively, outside and inside). I got a set of four from Amazon for about $5.

1 T-handle lug wrench with a 21 mm socket. Any auto parts store.

1 jack capable of lifting Model S weight. I bought a scissor jack at Autozone. Some carry bottle or floor jacks, but this seems like too much weight and space.

1 tire tote from TireRack. I think these are like $30 for 2. I had one lying around.

Once you get the tire and wheel, you’ll need to have the tire mounted on the BMW wheel. The local NTB did this for me; cost was about $25.

Of course, this is totally unapproved by Tesla and if you decide to follow this DIY you do so completely at your own risk. I make no warranty, express or implied, about the function or safety of this setup. Etc.

 

[4SUPER9]

Thanks JST. This is much appreciated.
Which scissor jack did you buy?

 

[caddieo]

Sure, here you go, all in one place:


1 steel temporary spare wheel from a BMW X5, BMW part number 36-11-6-768-861. These are available from any BMW dealer, or online from www.getbmwparts.com. http://www.getbmwparts.com/parts/in...1-6-768-861&action=oePartSearch&siteid=214672
Cost: About $75.

1 155/80 18 compact spare tire. These are available new for about $300, but you can find them used for a lot less. Look for the compact spare tire assembly from a Mercury Marauder or Ford Escape Hybrid. I found a number of them for sale at Automotix.net, a wrecking yard aggregator, for about $150. Note—the automotix search engine makes it seem like all you are getting is a wheel, not a tire. I received both when I ordered, but another forum member called and could not get them to confirm the tire would come, too. YMMV, as they say.

2007 Ford Escape Wheel (Used VIN H 8th digit, Hybrid 18x4 compact spare aluminum) For Sale - Buy Ford OEM Parts

1 74.1 mm to 65 mm centering ring adapter (basically just a piece of plastic with those diameters, respectively, outside and inside). I got a set of four from Amazon for about $5.

1 T-handle lug wrench with a 21 mm socket. Any auto parts store.

1 jack capable of lifting Model S weight. I bought a scissor jack at Autozone. Some carry bottle or floor jacks, but this seems like too much weight and space.

1 tire tote from TireRack. I think these are like $30 for 2. I had one lying around.

Once you get the tire and wheel, you’ll need to have the tire mounted on the BMW wheel. The local NTB did this for me; cost was about $25.

Of course, this is totally unapproved by Tesla and if you decide to follow this DIY you do so completely at your own risk. I make no warranty, express or implied, about the function or safety of this setup. Etc.

Am I correct in understanding that the centering ring adapter is for the Ford wheel? Or is it for both the BMW and the Ford wheel?
Thanks for the wheel/tire summary and for the answer to my question.

 

[JST]

Am I correct in understanding that the centering ring adapter is for the Ford wheel? Or is it for both the BMW and the Ford wheel?
Thanks for the wheel/tire summary and for the answer to my question.

The centering ring is for the BMW wheel, which has a 74.1 mm hub diameter. You don't really need this; the wheel is held on by the bolts. But it makes it easier to put on and get centered properly.

The Ford wheel you don't use. I think it has 114.5 mm bolt spacing, so it's of no use to you. Once you strip the tire off, you can recycle or sell it.

As for scissor jacks, it was the autozone 1.5 ton unit. This one, I think.

http://m.autozone.com/autozone-mobile/en/accessories/Tools-Garage-and-Equipment/Jack/_/N-255z?searchText=Scissor%20jack

But I'm not convinced this is the best option. It's just the one they had in stock at the closest store. If I were doing it from scratch I might search around a bit and see what I could find.

Oh, I also have a 6" scrap piece of 1x4 that I carry in the car to put between the jack and the lift point.

 

[Cool-Model S]

JST - Thanks for all the work you have done to solve this problem. I took a drive to CA and back (1500 miles round trip) this past weekend and took your suggestions to have the spare kit for peace of mind. I did not have to use it but having it made me drive without worries.

Attached you will see the pictures of the products I used. I have a 21" wheel and the 145/80/R18 wheel did fine. I put it on for a test drive. Drove about 6 miles on winding roads up to 50 miles/hour. No issues, no error messages. I would only use it on front wheel. I did hear squeaking type of noise while making right turns on curvy roads at 25-30 miles/hour. Not sure what that was. But in an emergency this will work to get to a nearest tire shop. Everything fits perfectly in the frunk.

I borrowed the tire from a friend but I would like to have a 155/80/R18 tire instead. I am having a hard time finding this. If anyone knows where to find - please let us know.

Again thanks for the good work - JST

 

[JST]

JST - Thanks for all the work you have done to solve this problem. I took a drive to CA and back (1500 miles round trip) this past weekend and took your suggestions to have the spare kit for peace of mind. I did not have to use it but having it made me drive without worries.

Attached you will see the pictures of the products I used. I have a 21" wheel and the 145/80/R18 wheel did fine. I put it on for a test drive. Drove about 6 miles on winding roads up to 50 miles/hour. No issues, no error messages. I would only use it on front wheel. I did hear squeaking type of noise while making right turns on curvy roads at 25-30 miles/hour. Not sure what that was. But in an emergency this will work to get to a nearest tire shop. Everything fits perfectly in the frunk.

I borrowed the tire from a friend but I would like to have a 155/80/R18 tire instead. I am having a hard time finding this. If anyone knows where to find - please let us know.

Again thanks for the good work - JST

Thanks for the kind words. The fact that the 145/80 18 tire works on the car without error messages is really significant. Those tires are a lot easier to find than the 155.

 

[KeithM]

I just carry a Tesla wheel & tire as a spare when needed. As you can see, the factory 19" wheel fits in the frunk. A Tesla 21" wheel assembly fits the frunk also. Be careful of the Tesla lug nuts. They have a crimped on chrome cover which is a bit fragile. If you don't get the socket all the way on the lug nut, you can easily damage the nut which makes getting the prescribed 129' lbs of torque difficult or not possible. Make sure the socket is bottomed out on the lug nut before applying torque to remove or tighten the nut.

A 21mm 6 point deep socket fits the lug nut. Don't use anything smaller than a ½" drive wrench. I use a 6" lenth of 2x4 on top of the jack to be sure it doesn't touch anything outside the jack pad to avoid damaging the edge of the battery. In addition to a "click" style torque wrench, a breaker bar is very handy as are a couple of extra pieces of 2x4 to chock the car when jacking.

 

[Larry Chanin]

Attached you will see the pictures of the products I used. I have a 21" wheel and the 145/80/R18 wheel did fine. I put it on for a test drive. Drove about 6 miles on winding roads up to 50 miles/hour. No issues, no error messages. I would only use it on front wheel. I did hear squeaking type of noise while making right turns on curvy roads at 25-30 miles/hour. Not sure what that was. But in an emergency this will work to get to a nearest tire shop. Everything fits perfectly in the frunk

Thanks for the information.

Would you mind elaborating on why you would only use this arrangement of the front wheels?

Larry

 

[4SUPER9]

I just carry a Tesla wheel & tire as a spare when needed. As you can see, the factory 19" wheel fits in the frunk. A Tesla 21" wheel assembly fits the frunk also. Be careful of the Tesla lug nuts. They have a crimped on chrome cover which is a bit fragile. If you don't get the socket all the way on the lug nut, you can easily damage the nut which makes getting the prescribed 129' lbs of torque difficult or not possible. Make sure the socket is bottomed out on the lug nut before applying torque to remove or tighten the nut.

I seem to be getting conflicting information on this. I was under the impression that the Tesla wheel would not fit in the frunk. It obviously does for you. Is it that some of us have different frunk sizes?

 

[KeithM]

I seem to be getting conflicting information on this. I was under the impression that the Tesla wheel would not fit in the frunk. It obviously does for you. Is it that some of us have different frunk sizes?

There are two different frunk sizes. My car was manufactured in November, 2013 and has the later frunk. To my knowledge the difference between the early and late frunk is only related to the size of the "microwave", the early cars having a larger one. I have the WeatherTech Tesla mat in the frunk. When I got the mat at the SC, we were unsure of which size would fit. The older style was much too large to fit in the microwave hole, but the new style fit fine. As I recall, the difference in microwave size was related to depth, the width being the same. I did not notice any difference between the fit of the mat in the main area where the tire in the picture is located. If this is true, the tire should fit in any frunk. FYI - the tire in the picture I posted is the Tesla supplied Michelin Primacy. It has only 3,000 miles, so there is little tread wear. It is in there because I installed a nearly new set of factory 21" wheels with Continentals and needed to bring my 19's home. (3 in the back, one in the frunk.). The 21" wheel/tire combo also fit in the frunk.

When placing the spare in the frunk, I find if the wheel is tilted slightly with the portion of the tire to the rear being low, and the tire inserted just below the two top attachment fittings for the net, that once it reaches the aft limit, the front drops down easily, but it is a snug fit. If carrying the tire as a spare, I would invert it to allow space for a jack, torque wrench and breaker bar on top. There is no problem with height to prevent closing the hood.

 

[jerry33]

Would you mind elaborating on why you would only use this arrangement of the front wheels?

The front wheels are free-rolling so there's no possibility of drive train damage. Perhaps this isn't actually an issue, but do you really want to take a chance?

- - - Updated - - -

I seem to be getting conflicting information on this. I was under the impression that the Tesla wheel would not fit in the frunk. It obviously does for you. Is it that some of us have different frunk sizes?

That seemed to be true for the very first cars and for 21" tires. I haven't seen any recent posts where it was true for 19" tires. (I haven't personally verified that a 19" tire will fit in my frunk--and in any event I use the frunk for shirts and pants in lieu of a suitcase, so I'm not keen on putting a tire in there.

 

[HankLloydRight]

Well, wouldn't the outside diameter of both 19" and 21" wheels+tires be almost the same? So the rim size really shouldn't matter. I'm storing a 245/35/21 spare tire in my frunk without the rim. Don't see why it wouldn't fit if it were mounted on a 21" rim. although it is a snug fit, I don't see any reason it wouldn't fit on a rim, assuming the tire is not inflated to be flexible enough to fit.

 

[jerry33]

Well, wouldn't the outside diameter of both 19" and 21" wheels+tires be almost the same? So the rim size really shouldn't matter. I'm storing a 245/35/21 spare tire in my frunk without the rim. Don't see why it wouldn't fit if it were mounted on a 21" rim. although it is a snug fit, I don't see any reason it wouldn't fit on a rim, assuming the tire is not inflated to be flexible enough to fit.

It's not the diameter, it's the width and whether the hood will close. the 21" tire is more square (has a wider tread) than the 19" tire. The tires have always fitted diameter-wise. If the tire touches the hood it will likely dent it.

 

[HankLloydRight]

It's not the diameter, it's the width and whether the hood will close. the 21" tire is more square (has a wider tread) than the 19" tire. The tires have always fitted diameter-wise. If the tire touches the hood it will likely dent it.

How much wider is the 21" tire mounted to a rim? (assume 245 and not the P+ 265s). Looking at my 4 mounted (and inflated) tires, the tires are pretty flush with the rims. And there seems to be reasonable clearance between my tires and the frunk hood.

 

[JST]

Well, wouldn't the outside diameter of both 19" and 21" wheels+tires be almost the same? So the rim size really shouldn't matter. I'm storing a 245/35/21 spare tire in my frunk without the rim. Don't see why it wouldn't fit if it were mounted on a 21" rim. although it is a snug fit, I don't see any reason it wouldn't fit on a rim, assuming the tire is not inflated to be flexible enough to fit.

They are similar in terms of diameter, but not exactly the same.

As for using a compact spare on the rear--I wouldn't worry about hurting the drivetrain. That's what differentials are for, and if the diameter is close enough that it doesn't freak out the electronics, I doubt it will be an issue for the mechanicals.

I haven't test fit the 18" compact wheel on the rear, though, so I am not sure it will clear the brake calipers back there. That's one minor issue.

The other is that since the MS is a powerful RWD car, I'd rather have the lower-traction wheel on the front than on the rear. Understeer is more predictable than oversteer, and why try and put that kind of torque through a 145 or 155 mm tire of you don't have to?

 

[Larry Chanin]

The front wheels are free-rolling so there's no possibility of drive train damage. Perhaps this isn't actually an issue, but do you really want to take a chance?

- - - Updated - - -



That seemed to be true for the very first cars and for 21" tires. I haven't seen any recent posts where it was true for 19" tires. (I haven't personally verified that a 19" tire will fit in my frunk--and in any event I use the frunk for shirts and pants in lieu of a suitcase, so I'm not keen on putting a tire in there.

Hi Jerry,

Thanks for your response.

It seems that if we can't reasonably expect to use a compact tire in the rear without fear of damage to the car, that the prudent thing to do would be to follow Keith's lead and use a standard tire.

I have 21" tires/wheels. Am I correct that a stardard 19" tire/wheel would represent a less expensive alternative to using a 21" tire/wheel spare and we should have no fear of damaging the drive train?

Thanks.

Larry

 

[KeithM]

I and many others have both a set of 19's and 21's. The easy solution is to carry one of the set not currently installed for a spare. No reason it is unsafe to mix them.

 

[jerry33]

I have 21" tires/wheels. Am I correct that a stardard 19" tire/wheel would represent a less expensive alternative to using a 21" tire/wheel spare and we should have no fear of damaging the drive train?

Driven reasonably (not too fast) that would be my expectation. I don't put the compact spare that came with my Prius on the drive axle. And of course, the 19" would be much less expensive than the 21" (unless you have already replaced a 21" for curb damage and have it already).