Switching from Run Flats to Michelins. What size Compact Spare fits?

[VN Vet]

I am done with run flats. I have the extended tire warranty but the dealer says my fronts are going bad due to alignment. They said they were wearing on the inside. Funny, the tread is equal across both tires, no uneven wear. Tread looks fine except the rubber appears to be deteriorating and chunks are coming off the tread areas.

These things are more trouble than they are worth. I am going to change to regular Michelins. The size on there now is 245 45 R19. The car is a 2017 X3 i28 four cyl. dual turbo. Other than this the car has been trouble free.

I know this has probably been addressed before but the info I get googling it is vague.

What size compact spare will fit? I only want something to get to a tire store, I not going to drive around on it for weeks like I have seen some people do.

thanks.

[2ndgenerationX1]

I am done with run flats. I have the extended tire warranty but the dealer says my fronts are going bad due to alignment. They said they were wearing on the inside. Funny, the tread is equal across both tires, no uneven wear. Tread looks fine except the rubber appears to be deteriorating and chunks are coming off the tread areas.

These things are more trouble than they are worth. I am going to change to regular Michelins. The size on there now is 245 45 R19. The car is a 2017 X3 i28 four cyl. dual turbo. Other than this the car has been trouble free.

I know this has probably been addressed before but the info I get googling it is vague.

What size compact spare will fit? I only want something to get to a tire store, I not going to drive around on it for weeks like I have seen some people do.

thanks.

We just switched from run-flats to regular tires on my wife's 2015 X1 around 2 weeks ago. After much research and asking on forums we've decided to go with a mobility kit: comes with a can of tire sealant, and a 12V compressor you plug in. Our shop recommended this as well, and I'm gonna order a kit tonight or tomorrow. We're not going with an actual BMW mobility kit btw, they're way overpriced imo. Instead I'm thinking we'll likely order a KIA kit on eBay which is very similar but a lot cheaper. We debated going the donut route too, but they're really hard to find in the size we'd need and are (imo) ridiculously expensive when you can find them.

[VN Vet]

Thanks. I thought about putting a kit together, didn't think about the KIA. I'll have to google that or check fleabay.

I'm still going to look for a donut. There has to be one with a bolt pattern that fits (I hope)

Thanks again

[2ndgenerationX1]

Thanks. I thought about putting a kit together, didn't think about the KIA. I'll have to google that or check fleabay.

I'm still going to look for a donut. There has to be one with a bolt pattern that fits (I hope)

Thanks again

I just ordered our Kia kit this morning on eBay for $40 shipped. I'll tell you, I thought since eBay has the kits cheaper - from wrecked cars I'm guessing - that maybe we'd spring for the actual BMW kit. But the BMW and Kia kits look IDENTICAL side by side in the pics, the only apparent differences is one says BMW, one says Kia - and the BMW version costs twice as much. Also I watched a Youtube vid put out by Kia that shows the tire inflation process. Looks like something my wife won't have any problem if I'm not with her.

Post a link if you find a donut that will work. I've searched and given up. Flat tires are pretty rare these days so I'm mostly hoping for the best, lol.

[tdavis5008]

Something to think about with spares on a vehicle with full time all wheel drive is that there is a viscus clutch between your front and rear axles. If one wheel has a rolling circumference that differs from the other wheels, this will stress the VC causing it to over heat and to fail prematurely. And I'm sure they're not cheap. I don’t know how many miles it takes for this to happen, but why risk it. Green slime and plug kit with an air compressor seems like the way to go for me.

[e30luv318i]

I also built my own little kit. I got a nice little compressor, flat fix, and a plug kit. I got it all off amazon for cheap and threw it under the trunk floor ... (where the spare tire SHOULD BE!!!!!!)

[richardodn]

Something to think about with spares on a vehicle with full time all wheel drive is that there is a viscus clutch between your front and rear axles. If one wheel has a rolling circumference that differs from the other wheels, this will stress the VC causing it to over heat and to fail prematurely. And I'm sure they're not cheap. I don’t know how many miles it takes for this to happen, but why risk it. Green slime and plug kit with an air compressor seems like the way to go for me.

BMW only used a VC in the old E30 and E34 cars. The early X5 and e46 3 series used the DSC system to limit slip by applying the brakes on the slipping wheels. The xdrive systems introduced in 2003 on the X3 and e46 uses an electronically controlled wet clutch to achieve front to rear torque split. However your advice is correct and it is best to keep all the wheels with the same circumference.