Take a car place a system that alows the tire pressure to be varied on the fly as is already done with some off road vehicles and trucks and wire it to sensors that detect wheel slippage. When the wheel or wheels break loose the system lowers the pressure in that wheel or wheels in order to gain more traction, It then reinflates the tire to its proper level once traction is restored for better fuel economy and tire life.
The system can also be designed to reduce pressure before the wheels break loose such as during hard manuvering, breaking, accelerating (if vehicle has the power to burn rubber), as well as warn of slow leaks and maintain tire pressure untill it can be fixed.-- Spaceman Spiff, Feb 10 2009 Please expand on 'that's where my idea comes in'....-- Skrewloose, Feb 10 2009 Is it half term somewhere? [mfd removed re: below. As you were!]-- gnomethang, Feb 10 2009 My bad, I posted by accident before I was done:)-- Spaceman Spiff, Feb 10 2009 Sounds like a good idea, but could be tricky to get to behave well, as events such as those you've described above tend to happen rapidly, and suddenly dropping the pressure in the tyres is gonna make the driver worry quite a lot!
A system that allows the pressure to build gradually on the motorway and drop as you get onto 'local roads' then back up for in town might work well for the economy/ride tradeoff though.-- Skrewloose, Feb 10 2009 I understand that low pressure allows you to travel on sand, one of Israel's battle tricks.-- MercuryNotMars, Feb 10 2009 as a car nut and amateur autox and rally participant I can tell you that unless there is something really special about your tire design this idea simply will not work. Dropping the tire pressure can increase traction in some situations, it can also significantly decrease it. For any surface and speed there is an optimum pressure. If you suddenly reduce the pressure in the tires you will also suddenly change the handling of the car. The driver is already in a tight place, he/she needs to figure out what to make the car do, given the limits they are experiencing, making the car more unpredictable at that moment seems a frightening idea. Remember also that tire treads are design to wear and grip well at around the same pressure. Raising or dropping a lot defeats the design of the tire, usually destroying both the grip and the wear life. When I autox on clean tarmac I usually use a hard compound tire at 7-10 psi up, not down, for maximum grip.-- WcW, Feb 10 2009 [WcW] You are correct that as explained it probably would be a liability (a pressure increase can also be used where conditions warrent) but as with any vehicle system it would require a lot of testing and refining to minimize risks and maximize benifits.
One thing that it would need to be able to do is detect what kind of surface it was driving on in order to make proper adjustments, mabey with a laser or radar type device?
As for tires they can be designed to maximize the benifits of this system.-- Spaceman Spiff, Feb 10 2009 you need a tire that deforms into a narrower low resistance high wear tread at highway speed but that relaxes into a high grip treaded footprint the instant you turn or touch the brakes. What about the idea of a separate inner tube built into the tread of the tire that achieves this with a separate smaller airmass. This would allow more rapid adjustments and gives a good fail-safe. And since the problem here is primarily one of management why not mount the system inboard the rim. It could detect that braking, cornering, or acceleration, was happening (force applied to the rim) and deflate the traction bead with a simple valve system. When the tire is spinning dead center with no extreme loads a pump built into the rim itself would inflate the high economy band, if load that exceeds a limit is applied that air is dumped back into the body of the tire (using air from the inside keeps everything clean). This could function in a fraction of a second and cycle constantly if needed.-- WcW, Feb 10 2009 For road surface detection you could use a voice recognition system, with the driver dictating conditions to the car's computer. Example, "Road surface: wet ice!"-- Laughs Last, Feb 10 2009 random, halfbakery