Hyperinflating tires

[cfg83]

trikkonceptz -

Originally Posted by trikkonceptz

Back in the early 90's I think a company marketed a wheel which was actually 2 wheels in place of one. It looked like two spares were bolted on to each side of the car. The company claimed it improved road handling, wet weather traction and reduced rolling resistance, does anyone remember those? Or am I having an acid flash back?

I think you are talking about this?

Aquachannel tyres.
http://www.carbibles.com/tyre_bible.html

Towards the end of the 90's, there was a gradually increasing trend for manufacturers to design and build so-called aquachannel tyres. Brand names you might recognise are Goodyear Aquatread and Continental Aquacontact. These differ noticeably from the normal type of tyre you would expect to see on a car in that the have a central groove running around the tread pattern. This, combined with the new tread patterns themselves lead the manufacturers to startling water-removal figures. According to Goodyear, their versions of these tyres can expel up to two gallons of water a second from under the tyre when travelling at motorway speeds. My personal experience of these tyres is that they work. Very well in fact - they grip like superglue in the wet. The downside is that they are generally made of a very soft compound rubber which leads to greatly reduced tyre life. You've got to weigh it up - if you spend most of the year driving around in the wet, then they're possibly worth the extra expense. If you drive around over 50% of the time in the dry, then you should think carefully about these tyres because it's a lot of money to spend for tyres which will need replacing every 10,000 miles in the dry.

CarloSW2

[ttoyoda]

There used to be a tire sold with a really deep groove in the center.. It sort of looked like this patent.

http://www.google.com/patents?id=zds...BAJ&dq=6123129

[cfg83]

trikkonceptz -

Here's another one :

TwinTire
http://www.carbibles.com/tyre_bible.html

This was an idea from the USA based on the twin tyres used in Western Australia on their police vehicles. It's long been the practice for closed-wheel racing cars, such as NASCAR vehicles, to use two inner tubes inside each tyre, allowing for different pressures inside the same tyre. They also allow for proper run-flat puncture capability. TwinTires tried putting the same principle into effect for those of us with road-going cars. Their system used specially designed wheel rims to go with their own unique type of tyres. Each wheel rim was actually molded as two half-width rims joined together. The TwinTires tyres then fitted those double rims. Effectively, you got two independent tyres per wheel, each with their own inner tube or tubeless pressure. The most obvious advantage of this system was that it was an almost failsafe puncture proof tyre. As most punctures are caused by single objects entering the tyre at a single point, with this system, only one tyre would deflate, leaving the other untouched so that your vehicle was still controllable. TwinTires claimed a reduction in braking distance too, typically from 150ft down to 120ft when braking from a fixed 70mph. The other advantage was that the system was effectively an evolution of the Aquatread type single tyres that can be bought over the counter. In the dry, you had more or less the same contact area as a normal tyre. In the wet, most of the water was channeled into the gap between the two tyres leaving (supposedly) a much more efficient wet contact patch. History is cruel to those who buck the trend, and as it turned out this system was just a passing fad. Their products disappeared around 2001 and the website vanished shortly thereafter. I've not seen any trace of them since. Daunltess Motor Corp are the last remaining suppliers and they have all the remaining stock.
For an independent opinion on TwinTyre systems from someone who used them avidly, have a read of his e-mail to me which has a lot of information in it.

Like Frank says, I don't think this was for LRR, it was for traction and increased puncture proofing.

CarloSW2

[aerohead]

Originally Posted by tasdrouille

Good luck finding THE answer, as such a thing does not exists. I'd go with RH77's advice.

Capri, I can't wait to see your take on hyperinflation. You already stated you had access to a lot of information under normal operating conditions, but this is hardly useful in regards to hyperinflation.

If I was a tire manufacturer, I'm pretty sure I would fund studies to test the limits of my tires for liability purposes.

Ok so to anyone, I would like to get arguments against running at 50 psi a tire which is rated for 44 psi. What I would also like, is that for every argument you make, you explain the basis of that argument and/or provide a credible source.

I saw this discussion last week and have been looking at some of my old articles and SAE stuff.-------------The nuts and bolts of it seems to be that you don't exceed the max. rated pressure embossed on the sidewall of the tire.-------------While under-inflating below the manufacturer's recommended inflation pressure will cost you fuel and risk you a blow out and rollover death or spinal-cord injury in an SUV,over-inflating the tires beyond recommended pressures will reward you with no measurable improvement in mpg.-----------------Concept-tires as GM uses on Ultralite are low-aspect-ratio,18-inch,65-psi,with curvature cast into the sidewall to allow some flexure,while maintaining the contact patch.Rubber compounds are black-art high-hysteresis compounds which somehow also have reasonable dry and wet traction characteristics.Tread width and mass are minimized for low aerodynamic loading and low polar-moment-of-inertia.---------------Temperature ratings are a big deal in tire technology and determine whether your dead or alive should you loose pressure while driving.-----------At Bonneville,I was required to inflate the tires on the CRX to 45-psi,minimum ( higher than max pressure rating ) to forestall standing wave,heat build-up,and catastrophic tire failure.at top-speed.As soon as the event was over,I reduced pressure to Honda specs.I got 60.6 mpg to the West Coast and back to Texas running normal pressure.----------Factory pressures are set for braking bias,and determine whether the car will oversteer or understeer,once the limits of adhesion are reached.Carmakers like cars to break loose at the front first,then a simple steering input can restore direction.Altering pressures with indescretion could allow the car to swap ends violently ,when pushed in an emergency maneuver.Please don't gamble with your lives for the sake of a liter or gallon of fuel.

[trikkonceptz]

Originally Posted by aerohead

Factory pressures are set for braking bias,and determine whether the car will oversteer or understeer,once the limits of adhesion are reached.Carmakers like cars to break loose at the front first,then a simple steering input can restore direction.Altering pressures with indescretion could allow the car to swap ends violently ,when pushed in an emergency maneuver.Please don't gamble with your lives for the sake of a liter or gallon of fuel.

Not that I don't agree with this statement, but the same industry also set FE standards that are inaccurate. You can take any vehicle and driving it sensibly with no mods and exceed its ratings. This is an industry that encourages wear and tear, it is how they stay in business. There is no money in the car that will not break down. Therefore I feel more confident stating that any part manufacturer will test and publish results for their product not to the most beneficial limits of the consumer but to the most beneficial limits of the manufacturer, ie to generate future revenue.

This post has gotten quite lengthy and the worst documented conclusion for overinflation is a higher probability for puncture due to debris.

[whitevette]

Originally Posted by IndyIan

This is kind of a balancing act as we are accepting slightly lower traction to increase mpg and save the environment and $$ but buying new tires more often costs both...

Its a multidimensional math problem for sure. Traction vs. mpg vs. monatary cost vs Enviro cost...
Ian

... and I might add "hospital fees" and "undertaker fees" to this multidimensional equation. Your tires are your life at speed; the contact patches are your only contact with the future.

[PaleMelanesian]

Originally Posted by IndyIan

This is kind of a balancing act as we are accepting slightly lower traction to increase mpg and save the environment and $$ but buying new tires more often costs both...

(emphasis mine)
Higher inflation leads to buying tires LESS often, not more often, since the wear longer and more evenly.

[MazdaMatt]

I saw the study that that point came from when I rejected that point previously. The even wear was with "more pressure" relative to not enough. The test that was presented to me did not involve inflating beyond max sidewall pressure and to assume that more evenly distributed wear and less overall wear continues through even higher pressures is an extrapolation you can not make. A "hyperinflated" tire will wear in the centre faster than a "proper inflated tire" will.

[PaleMelanesian]

No study I'm quoting - real life experience from me and others around me.

Prius tires at Toyota's recommended 32 psi. My Civic's previous tires looked almost this bad, at 5 psi above the recommended, but still 7 below sidewall max.


Acura MDX tires at 50 psi, after 60,000 miles.


2005 Honda Accord tires at 101,000 miles, 60 psi for the lifetime. They're about due for replacement, well beyond their expected lifespan.

[MazdaMatt]

3 different tires on 3 different cars at 3 different life spans really doesn't prove anything.