Mini runflat tyres - daveyjp
Apparently they can't be plugged if you get a nail in one - said nail has not been removed and tyre is still inflated, no tyre monitoring warning so inflation OK.

Is this true or is a colleague being ripped off? Replacement is £130 + fitting.
Mini runflat tyres - daveyjp
Now found them at £111 - or alternatively BMW dealer for £175!
Mini runflat tyres - y2k+4
But aren't MINI tyres quite small? Thats a shocking price for just one! Out of personal interest, aren't these things covered by the tlc package?
Mini runflat tyres - daveyjp
205-45-17 84V - far from small. Larger than the majority of cars, hence the cost. They are only available as runflats, no 'normal' alternatives (according to mytyres and blackcircles). Tlc only covers basic servicing, not normal wear and tear.
Mini runflat tyres - Aprilia
Price sounds about right. I wouldn't drive around with a nail in though!

Eric
Mini runflat tyres - Honestjohn
Apparently manufacturers are not allowed to fit runflats without Tyre Pressure Monitoring Systems. (Now I realise I misinterpreted the first post. He meant the TPMS had not activated because there had been no loss of pressure. In that circumstance there is a chance that the tyre is repairable.

HJ
Mini runflat tyres - Adam {P}
Sorry to go slightly off topic but how do the monitoring systems work? They sound fantastic - do they really tell you what your tyre pressure is in the car and if your tyres are a bit flat?
Mini runflat tyres - daveyjp
They do tell you the pressure and if they drop below a preset level a warning sounds. They work via a transponder located inside the wheel.
Mini runflat tyres - Adam {P}
How though? Is the transponder inside the tyre and can detect pressure or is it something more advanced?
Mini runflat tyres - AR-CoolC
The one in my car doesn't tell me the actual pressure, but warns when the pressure has dropped by a certain amount (can't remember what off hand)

Mini runflat tyres - Honestjohn
Maybe worth repeating here. The huge advantage of runflat tyres is you don't have to stop and change a wheel. If you have ever done that on a hard shoulder, even with police 'protection', you will never want to do it again. Especially an offside tyre. One inadvertant step back a couple of feet and you are road kill by a 40 ton HGV.

HJ
Mini runflat tyres - rtj70
I think there are two types. e.g. the Laguna II used some sort of special valve plus a "transponder" in the tyre and could relay tyre pressure info. The simpler method is to make use of the traction control sensors to measure wheel speed... loss of pressure will mean wheels turn at differing speeds.
Mini runflat tyres - rtj70
I should have said ABS and on Traction Control of course. Doh.

Also just found this via RoSPA: www.rospa.com/roadsafety/advice/motorvehicles/tpms...m
Mini runflat tyres - Adam {P}
That's pretty clever!

Thanks for the explanations!
Mini runflat tyres - Xileno {P}
I never found they worked very well on Laguna, although it was a very early model. Tyre fitters hated them as well, often the valve would snap off - ££££.

Useful but certainly no substitute for regular checking with one of the best inventions of all - a pair of eyes.
Mini runflat tyres - henry k
Useful but certainly no substitute for regular checking with one of the best inventions of all - a pair of eyes.

>>
Oh I wish it was that easy.
Easier if its a flat tyre but with low profile tyres it is not easy to see if it is just low on pressure.
Sadly I know of one fatality that the root cause was due to a nail in an ultra low profile tyre on a brand new car and it was not at high speed.

A proper on board pressure monitor is what is required. I hope this will become mandatory on all new vehicles.
Mini runflat tyres - AR-CoolC
I think there are two types. e.g. the Laguna II used
some sort of special valve plus a "transponder" in the tyre
and could relay tyre pressure info. The simpler method is to
make use of the traction control sensors to measure wheel speed...
loss of pressure will mean wheels turn at differing speeds.


The ones on my SEAT must have some sort of pressure monitor rather than just relying on wheel speed, as when I rotated the wheels to even out tyre wear the warning light (and annoying ponging) came on. This is bacause the rear tyres are set about 3psi higher than the fronts, so the monitor must be pretty acurate aswell.
Mini runflat tyres - rtj70
But how would a pressure monitor in a tyre know which end of the vehicle it is fitted too? Surely if you just swapped them around the tyre would still be reporting it was okay? I'd have thought it is using the ABS sensor because there'll be one for each wheel and it's noticed they're spinning at different speeds.

I'm with the poster that says checking them with your eyes and regularly with a tyre pressure gauge is best. But with run flats you do need something extra checking for you.
Mini runflat tyres - AR-CoolC
My understanding is that there is a sensor within each wheel arch that "reads" the transponder in the tyre, so when changing the wheels around the sensor in the wheel arch sees an instand change in tyre pressure of 3psi.

The difference in wheel speed must be rediculasly small, the front and rears had only a couple of mm tread depth difference.

This is only my understanding of how it works, and I'm more than happy to be corrected.
 

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