BMW's Michelin run-flats draw criticism... from Michelin
The Michelin run-flat tires fitted to certain BMW products are too heavy, degrade the vehicle's ride, and increase fuel consumption. So says Didier Miraton, who heads up the French tiremaker's Michelin Technology Center.
Miraton has an ulterior motive, of course. He wants to push his employer's PAX run-flat system (pictured to the right), which eschews the super-stiff sidewalls of typical run-flats in favor of an elastomer inner ring and an improved bead design. This design not only allows for improved handling and ride, but also provides over twice the endurance (125 miles vs. 50) after pressure is lost. The downside to such a system is that it requires a special wheel and can only be serviced by trained technicians, where as standard tires can be repaired virtually anywhere in the world.
In our opinion, anyone who's working on a solution to flat tires deserves mad props, since it's one of those nagging century-old problems that an outside observer might think should have been addressed before everyone expended so much energy on the issue of, say, dashboard covers that were hard to the touch.
[Source: Carsguide.com.au]
Reader Comments (Page 1 of 2)
naggs 7:07PM (6/23/2006)
i dont see how this run flat system can be much better than the stiff side wall solution. both add unsprung weight to a rotating mass. they already have a solution to flat tires, its called a spare and it is still the best solution to the problem.
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Buster Hymen 7:32PM (6/23/2006)
Also not mentioned that the PAX system is VERY expensive to replace for the consumer.
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John 7:32PM (6/23/2006)
Flat tires occur so seldomly.
Feeling up your nice, soft, smooth and sumptuous dash happens everyday.
seldomly
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John 7:46PM (6/23/2006)
soft touch, nice looking dash is much more important than that incremental improvement in tire technology.
Run flat tires lets you go an additional 125 miles... to find the next certified run flat tire technician to change your tire lol!
Regular tire lets you go one mile... to find a safe spot and change your tire right there, and be on your merry way!
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salguod 9:18PM (6/23/2006)
I can count on one hand the number of flats I've had in the past 10 years (that's something like 250,000 miles or so). Having fancy, expensive tires to save that extremely rare annoyance seems silly.
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Gardiner Westbound 10:36PM (6/23/2006)
The automobile manufacturers are the prime movers behind run flat tires. They want to save the cost of supplying a spare tire and jack, the complexity of designing on-board storage capacity and to gain the added packaging flexibility spare-less cars will yield.
Unfortunately early examples are disastrous; poor performing, very short-lived and colossally expensive to replace.
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Phil L. 11:05PM (6/23/2006)
A few thoughts on PAX:
- Note that PAX is NOT rated to tow a trailer in run-flat operation (I tow a popup camper with my minivan, so this is an issue I pay attention to). The manual says to park the camper at the side of the road while trying to find a certified PAX repair center. Hmmm, suddenly this isn't so convenient anymore. If the run-flat people really want market acceptance, the tire needs to be able to do everything the vehicle can.
- Last I checked, PAX service is not available in Canada. Think about this before taking your Odyssey Touring on vacation in Ontario!
- Honda instituted a wheel/tire exchange program to help deal with delays when servicing PAX systems. But complaints have surfaced about surprisingly high fees associated with the exchange - when new owners were told it would be a free (or nearly so) program during the warranty period. Read all fine print carefully; any clarifications need to be in writing. Yes, this can be a big deal: A set of PAX tires can be well over $1000 US.
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KazO 11:13PM (6/23/2006)
The only production vehicles in the US today with PAX tires are the Odyssey Touring and the Veyron 16/4 (does the Bug count as a 'production' car??).
The technical aspects of PAX are good (though I don't quite understand the asymmetrical inner and outer wheel diameters) but Michelin should have worked on getting lots of wheel and tire mfrs on board, and worked out availability of support infrastructure before putting these on the market. When Honda put the new Odyssey on the market, they had access TWO PAX tire mounting machines in the whole US. Honda had their dealers stock pre-mounted wheel/tire sets so they had something for Odyssey owners when they blew a tire.
BMW probabaly remembers their last bout with 3-letter Michelin technology (TRX) so their hesitance is understandable.
Speaking of, anyone want to take 5 BMW TRX wheels off my hands??
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Anthony Albertus 12:38AM (6/24/2006)
I had run-flats on my '03 MINI Crapper.. and they were utter crap-ola. The notion of needing no spare is insane. If you unfortunately get a flat more than 50 miles from a tire dealer that has IN stock, your exact tire (which is usually at least $250.00) you're basically stuck with an undriveable car. Like.. tow or no-go. Most shops won't fix them, never mind fit them, This whole concept is great if you drive a lot in scary slums and have a trust fund.. otherwise, it blows a flat.
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iQuack 2:53AM (6/24/2006)
Perhaps current run-flat tires aren't as good as they should be, but in this 21st Century, flat tires should be an annoyance of the past IMO.
It's been decades since I've had a flat, but the possibilty of having one at the worst possible time (when is it a good time?) is a concern.
Given the amazing technology that provides ABS, airbags all around, GPS systems, etc., it's odd that today's cars can be disabled by a flat tire.
I think flat tires should have disappeared at about the same time as 8-track tape players.
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jrhmobile 3:14AM (6/24/2006)
Yeah, right. This is Michelin talking ... the same guys who came up with TRX tires in the '80s ...
"I've got it. We'll make tires to fit metric wheel sizes nobody else uses. That way, they HAVE to buy our tires for replacement!"
Wrong-O, escargot-breath ... folks chucked the metric wheels in the trash with their used Michelin tires and bought normal replacements. How much you wanna bet that Michelin PAX wheel packages meet the same fate?
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Ari Kukkonen 3:27AM (6/24/2006)
runflats are good. You all buy safe cars allthough you are not having daily crahes.
You all buy ABS brakes in your car but you don't brake hard every day.
Same with ESP and other stuff.
Runflats are safer.
Bill Cosbys son was shot dead when he was changing a flat tire.
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peij 5:00AM (6/24/2006)
Fun-flat tyres are not about removing an annoyance, they are a safety feature (space and weight savings are just extra advantages). Car remains in the driver's control even when a tyre deflates extremely fast or even explodes (even at autobahn speeds).
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PBCrunch 9:00AM (6/24/2006)
You know, if you keep your tires inflated to the correct pressure you are MUCH less likely to have a flat. Of course only about 15% of people check their tire pressure on a regular basis so...
Those tire pressure monitoring systems are a MUCH better idea than this.
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MikeW 10:18AM (6/24/2006)
Rolls-Royce Phantom?
Michelin PAX first in the US
Didn't Nissan follow honda's lead in the minivan arena?
How does this reduce weight? No spare wheel and jack, what about the gain in unsprung weight? Michelin says 4 PAX wheels weight is equal to 4.7 regular wheels.
Winter tires?
Tire rotation on a Honda minivan, will the stealership do it for free?
Doesn't PAX answer a question no one asked? I would wait for the TWEEL.
Then again how many idiots put the mini-spare (inconvenience) on the front axle of a front wheel drive car. NHTSA should mandate large stickers that say NO!!!
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Pinkerton 9:54PM (6/24/2006)
The Cosby tragedy mentioned by Kukkonen is probably the most compelling argument for run-flats. BTW, that happened in LA late at night, a place not known for friendly motorists who stop to actually help you.
Obviously, conventional tires + a rinky dink spare is the lousiest OEM solution. Between the run-flats and a full size spare, both are a calculated risk depending on a number of scenarios unique to each car and driver.
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verdegrrl 6:27PM (6/25/2006)
Are cars so insular that nobody notices the feeling of a tire going flat? I have never actually had a "flat" tire - ever! This despite trips from Southern California to the Yukon and all over the western North American continent. Sure, I had a full sized spare and a can of fix-a-flat, but I've never used them.
Yes, I have caught a tire going flat, either by how the car drives, sits at a angle when I approach it, or a ticking sound of something caught in the tread while I leave the driveway/parking lot with my windows down. Really, how hard it it to check your tires once a week while filling up? Or if you are lazy, a tire pressure monitor system? Maybe I've been lucky, but I take care never to rub the sideall of the tire on a curb, park it hard up against t parking berm, or do anything else that might damage the sidewall.
IMHO until run-flats are available at minimal cost (after all, ABS is a fraction of the cost of an entire car, while run-flats are part of an ongoing replacement item with an expense that gets renewed every time you replace a tire), and offer little to no downside, they won't be the tire of choice. I recently drove an E90 with the run-flats and the bushings in the car felt distinctly soft and allowed more lateral movement than expected - I'm sure as an attempt to isolate the passengers from the harshness of the tires.
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Erling 2:56PM (1/09/2007)
Is there any test (video), on exploiding a tire while the car speed is 70mph?
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bill sommerfeldt 8:45AM (8/30/2006)
Now we find out most drivers are getting, at most, 30000 miles with these wonder tires. What a bunch of crap we were sold when we asked about the tires before purchase. All the hype was on saftey and being to run without a spare. Were we told it was $600 per tire to replace them after as low as 25000 miles? Nope....suckers are we all!
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Pat Caserta 5:00PM (2/22/2007)
I'm looking for someone in NJ w/ problems with their Honda Pax system tires - Please contact ASAP
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