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.
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Now found them at £111 - or alternatively BMW dealer for £175!
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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?
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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.
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Price sounds about right. I wouldn't drive around with a nail in though!
Eric
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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?
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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.
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How though? Is the transponder inside the tyre and can detect pressure or is it something more advanced?
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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)
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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.
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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
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That's pretty clever!
Thanks for the explanations!
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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.
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Useful but certainly no substitute for regular checking with one of the best inventions of all - a pair of eyes.
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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.
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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.
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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.
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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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