Michelin admit run-flats are flawed.

[Top Secret]

Originally Posted by Herald Sun

BMW's tyres fail the test.

Run-flat tyres fitted to BMWs are heavy, increase fuel consumption and have a negative effect on ride comfort - that's the opinion of Michelin, one of the companies that makes run-flat tyres for the German carmaker.
The candid assessment is made by Didier Miraton, the director of the Michelin Technology Centre.
He says carmakers such as BMW pushed for run-flat tyres.
"The OEMs (original equipment manufacturers or carmakers) are motivated by the spare wheel suppression (removal) for the reason of cost and space. We are, of course, following them on that path because it makes sense," Miraton says.
BMW says run-flat tyres, which have thick re-enforced sidewalls, make sure customers do not lose control when they have a puncture.
It says the main reason for their use is safety, adding that customers can drive up to 250km on a flat at up to 80km/h.
Michelin has developed its own, more expensive run-flat tyre called Pax, which uses a roll of rubber around the hub of the tyre to keep the car running after a puncture.
It says Pax is a superior system to the run-flat used by BMW in Australia. The only car fitted with the Pax system in Australia is the Rolls-Royce Phantom.

Miraton says the run-flats it produces for BMW are not perfect.
"It is a very heavy tyre, there is additional cost, fuel consumption is higher because of the very thick sidewalls, and comfort is hampered," Miraton says.
Few dealers outside capital cities stock run-flat tyres, though they are available through BMW dealers.
Tyres are usually shipped overnight to retailers.
"To be frank with you, the issue of service is also quite substantial," Miraton says.
He feels the run-flat system used by BMW is not a long-term solution.
"We move forward, we do our best to innovate in that field, but we also see the limit of this concept."
Tyremakers including Goodyear, Dunlop, Continental and Bridgestone provide BMW with run-flat tyres, which are used on 1-Series, 3-Series and 5-Series cars with 17-inch or bigger wheels.
The X3 and X5 have spare wheels and the M performance cars have a repair kit instead of run-flats.

Link: http://carsguide.news.com.au/story/0...-21822,00.html

[warot]

I think that they are flawed as well, but that's the future of tyres. This technology is still new and once improvements are made, spares will be a thing of the past. One of the top 3 problems is how difficult they are to replace, and that isn't really BMW's fault.

[Michael]

Originally Posted by warot

I think that they are flawed as well, but that's the future of tyres. This technology is still new and once improvements are made, spares will be a thing of the past. One of the top 3 problems is how difficult they are to replace, and that isn't really BMW's fault.

You are absolutely right Warot. I think this is a great move by Michilin, however, to come out and say this is rather wrong. Interesting that BMW was pushing for this, but it made sense.

[Giannis]

IMO, runflats may not be a comfortable/econimic should be, but they are a big step towards more safe cars. It woulde be better though if those problems could be fixed. Though, i have never driven a car with runflats so that i can say if they work or not.

Anyway, does anyone have any experience with that repairment kit? I think Audi uses it in A4. What does exaclty has and does it fix the tyre properly?

[Mr. Mercedes]

I think it’s very unethical for Michelin to so blatantly undermine a manufacturer (BMW) who has provided good custom to their business. If anything they should be talking about the future of run-flat technology rather than lambasting BMW for having the guts to push tire technology forward.

[Michael]

Originally Posted by Mr. Mercedes

I think it’s very unethical for Michelin to so blatantly undermine a manufacturer (BMW) who has provided good custom to their business. If anything they should be talking about the future of run-flat technology rather than lambasting BMW for having the guts to push tire technology forward.

Yeah it is somewhat wrong by Michelin to do this, but you need to understand that they may be covering themselves incase something were to go wrong.Either way I hope to see Michilen, BMW and other manufaturers develop new techonlogy for tires.

[Snake Vargas]

IMHO it's the opposite - as a consumer and a world-citizen even before being a car fan, I'm glad they've had the guts to admit the shortcomings. Perhaps not naming any brand would be a better way, but it's better that they let everyone know that they realise there's problems rather than having the spin factory work overtime and pumping out some more marketing propaganda.

Refreshing.

Anyhow, runflats do have problems - in Australia, they're not very accessible out of town. Once you get out of major cities, it's not unusual to be more than 250km away from another major city. Runflats aren't well stocked. Also, will this have repercussions for law enforcers who use tyre spikes?

Anyhow, from a practical point of view, runflats are better than repair kits - if the sidewall gets gashed by a rock, then aerosol and gunk won't help at all.

[YoungWarrior]

runflats suck full stop.

[warot]

Originally Posted by YoungWarrior

runflats suck full stop.

Nice one...

This technology is still in the development stages. Future ones will be more comfortable, have longer range and probably have better grip, while at the same time being cheaper. Now it's just up to the people to accept this techonology. It just might take a while for garages to stock up with them.

[YoungWarrior]

Its true though, whenever one of my family members are buying a car that comes equipped with them I make sure that they ask for normal tyres instead.