Morphing Tire Reduces Rolling Resistance

Come to think of it, IF the ridge is only inflated AT speed, and 'instantly' deflated on braking, the additional tread wear might be negligible, though turning would tend to eat it up.

The 'dump' valve(s) could readily be tuned to support 1/4 of the car's rated loaded weight at rest (or at speed), and any higher pressure/load would dump the pressure and prevent it from inflating. Braking and accelerating would dump it. Hard turning would dump it. Overloading would dump it. Potholes or bumpy terrain would dump it. Another tire going flat (or dropping off its middle) would probably dump it, too.

So then the bladder would be inflated from the tire's own air, and only if the amount of weight/stress on the tire is small.

The air channels can be formed on the rim, where the bead of the tire meets metal. So one channel could be inflating the tire, and one channel can be inflating (or attempting to inflate) the center.

No brains needed at all for the center bladder, and inherently as safe from leaks as the tire is without it.

 

The whole idea here is to have the tires ALWAYS be inflated correctly, without any input from the driver, unless the TPM alerts them to a problem. For any car.

So something cheap and extremely reliable is required; not something like what the military would pay to build and maintain on the taxpayers' back, or for highly specialized off-road use. It's supposed to REDUCE cost and maintenance by taking care of the tires automatically, not spiral the maintenance out of control.

'Portable' 12 volt pumps only work for smaller vehicles, at lower pressures and take FOREVER to inflate them even a couple of PSI. The whole inconvenience of pulling the thing out of the trunk and going around checking the tires every week or two (which FEW people actually ever do) is what self-inflation is supposed to cure. As well as removing the need for a 'spare', as most modes of tire failures are a direct result of poor maintenance (not keeping the pressure right).

Not carrying a spare/jack/wrench is potentially a significant weight savings, too. No need to make/mold space for them. No need to carry them.

 

Thought the idea was to change tires for conditions. The CTIS does that. I don't think maintenance is high, but it adds to system cost. The system is simpler if it only has to inflate and not deflate tires. Most commercial trucks have them too. Those new fangled tires seemed to add to the cost of every tire. A CTIS just adds to the cost of the vehicle.

Which is why truckers use CTIS or some variant. With TPMS there isn't an excuse for low tires now. But I didn't think that is what the thread was about. Those self inflating good years seem to make each tire expensive as does this tire rolling resistance changing technology. If they get it inexpensive I'll be surprised. Do you know how cheap bike tubes are, and on the bike system that tire cost $95.

Many cars are going to fix a flat instead of a spare.

 

The thread is more about ways to make tires more efficient. In a way that consumers can afford. If it's not, then probably discussing other ways to 'raise the middle' than the news story's idiotic solution are 'off topic', too.

Properly inflated tires are more efficient than what is out there in the real world, now. Probably 80% of the 'raise a ridge' savings could be realized, fleet-wide, if tires couldn't generally be flat, even if the users ignored them.

With TPMS alone, different tires can still be down a few PSI, with no warning, and this degrades fuel economy and causes uneven wear. Many TPMS systems won't generate a 'warning' until one or more tires is substantially flat, as they work on counting rotations and noting some tires rotating more or less than others, not the actual pressure inside the tires. A freebie that comes from traction control hardware. In fact, with the traction control version of TPMS, all four wheels could be equally flat, but as long as they behave consistently, the computer won't ever notice a thing.

This gives users a false sense of security, and they will tend to be even more complacent about their tire maintenance. After all, the light hasn't come on, yet.

What works on an embarrassingly expensive military vehicle, or a $130,000~$180,000+ tractor/trailer that gets single digit fuel economy no matter what, from always dragging cargo, and has a big air compressor on a big diesel engine anyway (for the air brakes) won't necessarily work on a $20,000 'economy' car that competes with hundreds of other $20,000 cars.

 

Oh, and even if the TPMS idiot light is 'on', it doesn't mean the user will do a damned thing about it.

 

Hey the news was about a system that could provide a change in tires for low rolling resistance, normal dry, wet, snow. Pretty cool idea, but you pay every time you replace the tire. A Central Tire Inflation System (CTIS) you pay on the vehicle plus a small amount of maintenance. It also adds very little weight to the rolling mass. CTIS might even be less expensive than the spare tire if car volume is at a premium and it doesn't need to automatically deflate the tires. But auto deflation is needed if the tires are pumped up to be low rolling resistance and conditions call for lower pressure. Most people just slow down. Hey james bond had a system in his car, it might help to sell cars. Its a much bigger advantage if you are going off road though

Raise a ridge, I'm guessing you mean make the tires lower rolling resistant with a smaller patch. This makes tires less safe. You simply can go with less safe tires and realize most of the savings. They even cost less. The prius c comes with 14" tires in japan.

The rule IIRC is 25%. If you pump up your tires to 40psi and set it, I'm sure you'll be fine Seriously TPMS doesn't mean you don't need to periodically check your tire pressure. It should not be much of a problem, but to fix a slow leak until you actually get your tire repaired you need a CTIS. I honestly think all these idiot lights make people less responsible for maintenance. Having tires a few pounds different for a month isn't going to cause any major wear.

I wish I got out the door on my prius @$20K. Relax. I really like the idea of ctis. Like gps prices will come down. The prius isn't an ecobox. We already have an electric compressor. The system is much simpler if you just need to raise air pressure instead of lower it. But no, I was not recommending it on the prius. CTIS just looks a lot more competent than a good year version of those expensive bicycle tires.

 

Suspensions are designed to work with a wide variety of tires.

The most efficient on this tire is LRR, the safest will be rain or snow depending on conditions. That is why the tires have to change, the most efficient is never the safest when it comes to tires. Would you mountain bike on a racing road tire?

Run flats problems are extra weight and replacement cost. I would expect the same problems here.

 

Well, we'll see how much energy it takes to cause an unproven polymer to change the shape of a tire, raising the entire car a millimeter or two, and how many times it can be made to work before it fails, and how that energy gets delivered to it. Or not.

Versus air pressure, valves and bladders, which can all easily be manufactured into rubber and composites, and are known quantities with straight-forward and well understood engineering properties.

Whereas something to bleed/pump to a preset pressure could be purely mechanical, and exist in the tire/wheel. The valve its self could be preset electronically to harden/soften the ride with very little power, and that would be MOST of the benefit of raising the ridge.

An additional 'something' to bleed/pump from the tire's inner pressure to inflate a 'ridge' bladder would be almost as straight forward as the tire deformation pump on the rim. Actually, less problematic, as it wouldn't ever suck contaminants from the external environment.

Another minor issue with central compressor: On a Prius, the links are indeed solid, driving the center of the wheels, like almost all front wheel drive vehicles. Not a problem on the rear wheels, but on the front the air would have to go in from inside the transaxle machinery, through linkages milled hollow. Maybe all the way back to the planetary gears. An 'interesting challenge', if you're an engineer, and a 'horror show', if you're planning for mass production and controlling cost.

 

I don't think many current suspensions were designed with the idea of tires with morphing polymers in mind.

So I would think depending on the reality of the final product, that we are a several steps away from all of us going to Costco and slapping a pair of Magic Morphing Tires on our vehicles.

And that's what I said.- Most efficient is not usually the safest.

 

The car this is first set for if it makes it out of the lab is the mazda RX9. Mazda is rumored to be using some of toyota's hybrid tech in this car also.
Mazda RX-9 features Mighty Morphin' tire technology and energy absorbent skin

I would not expect a costco to carry them. I was agreeing that most efficient is not safest, which is why for a high tech car they may want to try to switch from efficient to safe depending on conditions.

Its not the suspension but the electronics that would need to be on the car. I doubt there will be many tire sizes, and I expect the tires to be expensive.