[E60MKF]

So what is the deal with run-flat tyres...?

If you get a puncture how long can you drive with them on?

I know you shouldn't exceed 50mph or brake harshly..

I always change them as soon as it comes up on iDrive but surely you can drive them for a day or two- isnt that the point of them?

Cheers

[....,,,,..,,..]

The main points are not having big blow outs and also being able to drive to a garage to get them replaced.

Although the latter does depend on where and when you get the puncture.

No you can't drive on them for a few days.

(Obviously you can, just would be bit crazy to).

[DTP1980]

If you drive on them for extended periods the internal structure ultimately gets destroyed. The tyre becomes unstable too.

You are not legally supposed to repair them and most reputable tyre fitters will not do it. If you get tyre failure causing an accident as a result of fixing it or having driven on them whilst deflated, if discovered, your insurance will be nullified as the RFTs are part of the safety system on BMW's just as your airbags are part of it. That's why you have to notify your insurer if they are swapped to non RFT.

[teaston]

Originally Posted by E60MKF

So what is the deal with run-flat tyres...?

If you get a puncture how long can you drive with them on?

I know you shouldn't exceed 50mph or brake harshly..

I always change them as soon as it comes up on iDrive but surely you can drive them for a day or two- isnt that the point of them?

Cheers

If you drive on them with zero or very low pressure then they can't be repaired! I still carried slime & a tyre inflator for this reason!

Might as well just get non RFT tyres then!

[TimMcC]

100 miles. After that it'll fail when it's ready.

Ended up doing 99 miles on one earlier this year due to when and where the puncture developed. Was a bit hairy, always get them changed as soon as possible.

[Lorcan]

We recommend you change to ordinary tyres.

[JustChris]

I drive well over a hundred miles back from. Oxford on a flat RFT and did occasionally pass over 50mph. Doubt I'd do it with the family onboard etc.

Hate the ride on them but it's greats carrying no spare and handy if some tool were to let all the tyres down!

[E60MKF]

Interesting!

Yesterday night on the way home from dinner I got a puncture, the chances! At least I can go to bmw and check out the gran coupe too!

[HighlandPete]

Originally Posted by E60MKF

So what is the deal with run-flat tyres...?

If you get a puncture how long can you drive with them on?

I know you shouldn't exceed 50mph or brake harshly..

I always change them as soon as it comes up on iDrive but surely you can drive them for a day or two- isnt that the point of them?

Cheers

As has been mentioned if zero or virtually no pressure the "run on flat" capacity will get used. Tyre will have done its job, even if it is being destroyed in the process. Distance depends on the pressure in the tyre, vehicle load and speed.

You can of course extend that range, say with a slow puncture, if you keep it pumped up.

Same applies to a non run-flat, if you drive around long enough with it at low pressure it weakens, but keeping a tyre pumped up with a slow puncture, can often get you out of trouble, or extend its range before you can get it sorted.

HighlandPete

[Slipperyshoe]

I had a slow puncture on mine and did 1500 miles ish on it. Was inflating every morning until new wheels and tyres came in.

On my old E90 I did 2000 ish miles with no pressure (two cracked 19" rims). Tyres were destroyed inside when we took them off.....the car supermarket I bought them from had set the pressures at 0 so I didn't get a warning. I couldn't prove anything but safe to say I will never be buying anything from a certain car supermarket Northampton way. Run flats are a great safety feature but I still choose to get them off asap!

And yes I know in an idiot for not spotting it straight away...first bmw and all that

[E60MKF]

So it turns out they sheered the valve when the car was in on Thursday! Absolute joke of a service today!!

[gatsojon]

Originally Posted by DTP1980

If you drive on them for extended periods the internal structure ultimately gets destroyed. The tyre becomes unstable too.

You are not legally supposed to repair them and most reputable tyre fitters will not do it. If you get tyre failure causing an accident as a result of fixing it or having driven on them whilst deflated, if discovered, your insurance will be nullified as the RFTs are part of the safety system on BMW's just as your airbags are part of it. That's why you have to notify your insurer if they are swapped to non RFT.

You should drive at reduced speed and for the shortest distance reasonably practicable. So I agree with that.

But what "law" are you referring to with respect to repair of Zero Pressure tyres? All major tyre manufacturers permit one repair within the tread (as with any non- ZP tyre), though any subsequent zero pressure running is not guaranteed.

The 'not repairable' line is only trotted out by organisations with a vested interest in selling a new tyre. BMW dealers are really good at this