The Prius definitely looks like Toyota’s technology demonstration vehicle. In the 2006 model, they have added a tire pressure monitor system. Pressure monitors clear the way for safe usage of Zero-Pressure Run Flat tires. Why didn’t Toyota add run flat tires to the Prius? The weight and fuel economy savings - by removing the spare tire and jack - plus the added benefit of freeing-up that space for use as additional storage, seems like a Prius kind of thing to do. Is run flat tire technology really ready for prime time . . . or at least Prius time? http://eu.goodyear.com/home_en/tires/runonflat/index.jsp Toyota, Goodyear sued over 'run-flat' tyres. (Wouldjaknowit, it involves a class-action suit filed by lawyer scum in the good ol’ USA :angry: ). http://www.busrep.co.za/index.php?fArticleId=2975207
These tyres will come in handy with that armored Prius on the other thread. When it Toyota going to add the quad .50 cal gun turret?
I understand that those kinds of run-flats are an entirely new type of tire-wheel (supposedly as big a difference as bias ply vs radial) and it could still hit or miss. From what I understand you cannot run "normal" radial tires on those rims so this point is still relatively large. Right now I know of Toyota (Sienna) and Volvo (S60 and V70) offering these packages, are there many others? Keep in mind that the run-flats on the BMW M's, Corvette, other high performance cars use a "normal" rim. Here is more info: http://www.michelin.co.uk/uk/front/affich....codeRubrique=31 Or am I just mixing things up?
The Toyota Sienna AWD uses runflats because there is no room for a spare with the driveshaft running to the rear wheels. My wife's Sienna is an AWD. Toyota uses standard wheels. The runflats mount right up on the standard wheels. Now Honda uses the PAX system which does require a special wheel. If you are interested in putting runflats on your prius, you might need to buy new wheels just because there may not be any runflats (RFT) in 15" size. I will say this, RFTs are MUCH heavier than standard tires. They are heavier because of the extra materials used to reinforce sidewall strength when the air is gone. Weight affects gas mileage, handling, and braking more than you might think. As you may know, the Prius uses very light wheels with very light tires. If you put on RFTs, you will need to reduce the weight of the wheels substantially in order to come close to the factory wheel+tire weight combo. This means new wheels, not because of a different bead design, but because you will need lighter wheels and perhaps move up to 16" or 17" in order to find some RFTs. They are not produced in every size, but limited sizes only.
Not sure about the zero pressure run flats, but there are some serious draw backs to standard run flats. Our other car is a Mini Cooper S which comes standard with run flats. After the tread ran down, I replaced them with traditional tires and even bought a spare tire to carry. The downside of runflats: stiff side walls result in a stiff ride, heavier tires X 4 negates the weight savings from not carrying a spare/jack, much more expensive, limited choices, most places won't repair/patch them so you have to buy a new tire, and finally they don't handle as well (though not as big a draw back in a Prius). They sound like a great idea, just not too practical. Peace out, DWrath
You forgot the biggest downside for run on flats, very few tire places are equiped to handle them and don't stock them. I heard of cases where people with run on flats took a trip to canada and got a flat.... they ended up waiting for a new tire to be shipped to them. Most people end up carrying a spare with them anyways. I have been told that if you ride a good distance on them when they are flat they usually can't be fixed and you will need a new one. I would never buy a car with RUN ON FLATS.
Are you sure about that?? One of the main causes of rolling resistance is the material of the tire flexing, so intuitively, you would think that the stiffer tire would actually *decrease* rolling resistance..
. . . Lexus specified that run-flat tire ride, handling and rolling resistance must equal conventional tire performance. . . . without increasing tire weight or sacrificing ride performance . . . http://www.accidentreconstruction.com/news/may01/053001a.asp
Trust me, the first thing Lexus owners do is replace the runflats because they ride so badly. Most of them take the chance without a spare just for a better ride. So, even if their goal was to make the tires "just like ordinary tires" they're not there yet.
My understanding is that most cars sold in the USA with run-flat tires are using either Bridgestone or Goodyear tires, and they don't require a special rim or tire insert. It's all done with stiff sidewalls, reinforcement where the sidewall and tread join, and with use of special materials in the construction. I did a little browsing on Tire Rack and man, Sienna owners really hate the run-flats. Some are only getting 15k miles or less out of each set, which is about 1/4th what they expected to get.
The new tire and wheel profile though doesn't have the ride drawbacks of the runflats because the rim has a support which you can drive the tire on, I think thats what they're talking about. The new wheel system is used on the Honda Odyssey for instance.
