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Vans & Minivans Run-flat, self-sealing, PAX tires for Minivans
1440 messages, Last post on Dec 07, 2009 at 6:59 PM
You are in the Vans & Minivans Forum. Your Host is Karens
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Replying to: joeb24 (Dec 12, 2004 2:49 pm) Steve, Host |
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Replying to: digiprod (Dec 11, 2004 3:54 pm)
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Replying to: gkkim (Jan 03, 2006 2:05 am) Seems like a pretty hefty premium to pay over and above an EX-L to me. I had no idea the Touring was really THAT much better. Maybe the Touring owner could recoup some of their expense by selling their PAX system on Ebay to someone who really, really wants PAX......
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Replying to: rorr (Dec 13, 2004 3:15 pm)
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Replying to: gkkim (Dec 13, 2004 5:06 pm) |
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Replying to: ramcfall (Dec 09, 2004 10:11 am)
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I think you're missing the point. We aren't dissing the safety advantages of RFT's. We just don't understand why Honda had to chose a proprietary system. We don't understand why Michelin couldn't developed a PAX rim which could ALSO accept standard tires if PAX tires were unavailable. We don't like the fact that if you have the PAX system, you are forced to STAY with the PAX system unless you want to incur the additional expense of changing out rims. We also don't like the fact that Michelin has tried this EXACT same scheme before (offering tires which were supposed to be a 'revolution' but required special rims which would NOT accept any other type of tire). This system was called TRX. It was an abyssmal failure. And it had much wider initial use by manufacturers than PAX currently has. Personally, I think the system would have had a much greater chance for success if people knew that, IF a PAX tire was unavailable, or IF they didn't like the ride/wear/noise of their PAX tires, they would have the option to choose a different tire. They would then be more willing to give PAX a try.
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Replying to: coach87 (Dec 13, 2004 11:31 pm) "The significance of Michelin's PAX run-flat tire is its decoupling of inflated and deflated performance. That is, unlike other extended-mobility concepts, PAX lets engineers optimize deflated performance independently of normal inflated operation. Its attributes offer benefits compared with conventional tire designs as well." "Unlike any other tire's bead technology, PAX anchoring is not pneumatic; it's purely mechanical....thus, since its independent of a tire's inflation pressure, the bead/wheel interface isn't compromised by deflation. In fact, this is the case even in extreme cornering." After several more comments about the origin of the PAX name and the nomenclature they use in defining the tire's size. He then goes on to say: "Michelin recently offered me several back-to-back tests to assess PAX technology. First, I got to autocross two Renault Scenics, one with PAX, the other with conventional tires, both at correct inflation pressure. By the way, PAX has been optional on this tidy Euro-only minivan since June 2001 and standard since January 2002. "By assiduously keeping my eyes off the tires, I was able to do this phase 'blind' with slow, moderately aggressive and car-control-teetering laps of each one. Differences were really subtle, though I sensed one car offered a bit more comfort on the easy lap and a bit more grip on the hot one. "Which car? The one on PAX. "Next came a street route with a new Honda Odyssey, the Touring model....this particular Odyssey had a flat left rear tire.....In moderate city driving, the principal giveaway was a slight rumble and a bit of ride harshness on broken surfaces..." "The last exercise was the most compelling: autocrossing an Audi A8L with its left rear PAX utterly deflated.....on hard right turns, the Audi's left rear felt initially like it was breaking away; this, as the tread structure realigned itself on the PAX inner ring. Then, it stabilized and developed grip....Pushed further the Audi could actully be pitched and caught around cones--this quite amazingly, with a flat rear tire." "What of PAX significance? The tire has already been standard equipment on the Renault Scenics and Roll-Royce Phantom and now on the Odyssey Touring. Its optional on Audi A4, A6 and A8 models (and rumored on a coming Nissan product) Michelin expects annual PAX adoptions to grow to between 200,000 and 250,000 four-tire fitments by 2005." The article then mentions that the PAX is amenable to SUV and minivan load ranges. (unlike Michelin's own Zero Pressure tires) Four PAX tires weigh less than 5 equivalent conventional tires. PAX rolling resistance is 12 percent better than a conventional tires and a huge 30-40 percent better than other run-flat tires (which are notoriously poor in this regard). Michelin says PAX will probably cost a 10-percent premium over a traditional non-run-flat tire. Then the author concludes the PAX portion of the article with this comment: "To me, the most compelling thing is that Pirelli, Goodyear, Sumitimo and Toyo have each licensed PAX technology for their own products. In fact, one of the concept cars at the Paris auto show was on Goodyear PAX tires." In the following portion of the article, the author discusses various tire pressure monitoring systems (TPMS). TPMS is mandatory for run-flat systems to let you know when you're tire has lost pressure. PAX uses a direct-pressure sensing system which has very good accuracy. Direct systems have a sensor within each wheel, measuring each tire pressure independently, and can display each pressure separately. Sienna and other systems use an indirect system that works on the principal that an underinflated tire has a smaller rolling circumference. By monitoring the differences between tires using ABS hardware, its possible to identify differences in inflation pressure. However, since indirect systems compare data over time, it won't necessarily provide a timely response to rapid deflation, and most likely cannot identify which tire is low and may not operate at all vehicle speeds. Also, if all four tires gradually lose pressure at about the same rate (for example through neglect), an indirect system won't identify an underinflation at all. A direct system is as accurate as its chosen sensor. Typically, 1-psi differences are identified. Indirect systems may not be capable of anything better than that required by the proposed NHTSA regulation (25 percent). I have also noticed that there are several tire changer manufacturers (for example, Hunter Engineering--go to Hunter.com) now marketing PAX system tools and kits for independent shops that can handle all the latest PAX combinations. I hope that the above has been helpful--GO FOR THE TOURING! I think the PAX system is not only the best run-flat system available, but will be successful. Hey--I remember back when tubeless tires were introduced. There was a lot of concern as to whether they would actually work. Some people even insisted om putting a tube in their tubeless tires.
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Replying to: rorr (Dec 14, 2004 7:04 am) As for the price point break mentioned for implementing non-proprietary RFT, there really isn't. The availability of those "non-proprietary" system is at best comparable. After looking at both the 05 Odyssey and 04/05 Sienna AWD, we called around the tire shops in the SF Bay Area and and came to the that conclusion. What non-proprietary does give one is the ability to put on a non-rft "regular" tire -- at which point, the comparison is moot because a blow out/flat of a regular tire and the trouble of being stuck on the roadside waiting. By 2007 when the TREAD act comes in place, one of the big stumbling block for implementing RFT will be in place. Cars will be required to have pressure monitors. The point that I was making is that (whether the PAX tires are successful), people can change out the PAX if they do no like the ride/wear/noise. There will be duds out there - TRX being the most notable. Fifty years ago no one believed that a radial tire was possible. Just a few years back, the motion pictures association spoke out against the VHS technology. Consumers will speak with their wallet and time will tell if PAX becomes a part of the evolution - or a roadkill.
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Replying to: ramcfall (Dec 14, 2004 10:11 am) Maybe the gas saved by the less rolling resistance of the tires will offset the 10% estimated extra cost. btw, I remember when radials replaced bias tires; that was a hot topic of discussion at the time. Especially since they cost more to buy. Steve, Host
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