BMW X3 M40i 21" space saver wheel question

[Stuart59]

Afternoon everyone,
Just wanted to share an experience and ask a question.
I've a 2019 BMW X3 M40i with the 21" wheels and run flat tyres. After only a few weeks I was unlucky to have an instant defation puncture on a Saturday night 12 miles from home. I drove home on the flat at 30 mph, the rim looked undamaged though I wouldn't have wanted to drive on it much further. The tyre was very hot and in motion was making a 'crinkly noise' (it wasn't making a noise initially so I presume it was well on the way to total failure). The actual tyre is a Bridgestone Alenza 001 RFT 245/40 R21 100Y.
A phone around on the Monday morning revealed a replacement tyre would be about £260 fitted but there was current difficulty sourcing one. The big national depot companies couldn't locate the exact tyre at all and the best a local mobile tyre fitting company could offer was a 30 day wait. I then decided to go down the BMW new car assist procedure due to the availability problem. The X3 was recovered to the nearest BMW service centre and a courtesy car provided. The next day the service centre phoned needing a payment of £443 before ordering the replacement tyre and then it would take 5 days as it was on back order.

Oh for the days when cars carried a proper spare wheel! So much for progress!

This experience has left me considering whether to obtain a space saver in future. I'm thinking if I carried one then I could have got the roadside assist to put the space saver on and then take the wheel to a local tyre fitter myself, saving £183, being able to keep the car and still not needing to turn a wheel nut myself.
The question..... Has anyone sourced a space saver for a similar car to mine? I'm reading comments on the net about problems clearing the brake calipers and wheel spacers being required for certain models. One BMW dealer told me there is no approved solution for my X3. Another offered an 18" BMW space saver for £257.50 plus vat but pointed out there isn't space to store it under the floor (I accept it would have to be strapped above floor). I don't want to buy one and then find out it doesn't fit. Can anyone advise? I don't specifically want a genuine BMW space saver either. Also anyone had any failures driving an X3 on a space saver for a long distance, they are quite a heavy car, I've read 50 miles is the limit? Does that mean that after 50 miles the wheel is a write off (metal fatigue perhaps).
Thanks for reading.

[Pica-Pica]

BMW or your BMW dealer should certainly know which minimum size would fit.

[Locknut]

Last question first: There is no reason why a space-saver would have to be scrapped after 50 miles.

[Pica-Pica]

Locknut said:

Last question first: There is no reason why a space-saver would have to be scrapped after 50 miles.

I believe that the 50mph for 50 mile limit on space savers is to keep any serious driving to a limit with an odd wheel/tyre on one corner.

[VerySideways]

Personally i'd just buy a spare front wheel and have it fitted with a new tyre.

The rolling radius front and rear is the same, so it would certainly get you out of trouble whether you had a puncture front or rear, even if the replacement tyre took a week to arrive.
Space savers are typically only good for up to 50 miles at up to 50mph.

Whether you choose to carry the spare all the time, or simply leave it at home, if you have recovery then at least you could get recovered home and change it?

I have a full set of winter wheels/tyres which effectively means i have 4 spares :-)

[Locknut]

VerySideways said:

.
Space savers are typically only good for up to 50 miles at up to 50mph.

,,,,,

I have taken down this post as explained later in the thread..

Edited by Locknut on Thursday 26th September 20:12

[Monty Python]

What caused the deflation? Was it something in the tread? If so, then it might be worthwhile getting a mobility kit (like Slime) or a tyre plug kit so you can try and repair the tyre when the problem occurs, then get it fixed.

[VerySideways]

Locknut said:

VerySideways said:

.
Space savers are typically only good for up to 50 miles at up to 50mph.

Those are the recommendations for runflat tyres.

Errr, no.
I've owned plenty of cars with space savers over the years, and they have ALL specified no more than 50mph, and usually suggest that anywhere from 50 to 70 miles is the maximum recommended driving distance.
Either way, if it takes the OP a week to get a replacement tyre that effectively renders his off the road for that time. If he's 40 miles from home then all the space saver will really do is get him home and then get him to the tyre shop.
Hence my suggestion that having a full size front (which would fit on the front or rear) would keep him mobile for the week until the new tyre arrives.

[Locknut]

VerySideways said:

Errr, no.
I've owned plenty of cars with space savers over the years, and they have ALL specified no more than 50mph....

Yes you are correct, especially about the 50MPH speed limit (although I have seen them being driven much faster by morons who obviously did not know what they were doing). As for distance: a runflat will eventually self-destruct if driven further than about 50 miles. A space-saver will go much further but obviously you should not set off on a long journey with one fitted. You couldl get many hundreds of miles on shorter trips near home provided you treat them properly, in particular the pressure must be correct, usually around 60PSI.

In short what I'm saying is that you can use a space-saver for hundreds of miles with common sense. However, this is a public forum and we don't know how the advice will be understood, so I am taking down my previous post.

[naturalaspiration]

I have a cheap chinese puncture kit off eBay and a small compressor in the boot. So far fixed three (!) punctures on my non run flat tyres (LPG tank in the spare wheel well) - all there times the tyres had swallowed a screw which went all the way in. Luckily not on a motorway.

[VerySideways]

naturalaspiration said:

I have a cheap chinese puncture kit off eBay and a small compressor in the boot. So far fixed three (!) punctures on my non run flat tyres (LPG tank in the spare wheel well) - all there times the tyres had swallowed a screw which went all the way in. Luckily not on a motorway.

Have you looked at Dynaplug? I have used at least a dozen over the last few years when i'm at work, and for fixing punctures which are nail/screw or similar based they are absolutely superb. Highly recommended.