Variable Width Tires

[DannytheRadomski]

With fuel economy being such a big deal currently I was thinking about low rolling resistance tires. I've heard that these can be more dangerous because there is less grip during cornering and braking. They are also less sport-oriented. In my thinking about cylinder deactivation, I was wondering if similar thinking could be incorporated into tires. If you could somehow alter the contact patch with the road while driving, you could save fuel. If the profile was narrow while on the straights and light corners but wide in the fun bends, you could save a considerable amount of fuel (I assume).

The two ways I was thinking that this could be implemented would either be through variable inflation or mechanically changing the shape. I already have seen studies shown over-inflation can improve fuel economy, but it also makes the car less safe to drive. If you could somehow have a reservoir that could change the pressure in the tires as you drove, you could change the shape of the tire. The only other thing I could come up with is having a supporting ring (like in some run-flat tires) that could somehow expand to make the tire taller and have a smaller contact patch. The biggest problem with this idea is that then the road bumps and holes would be sent straight to the rim.

I'm sure there is a much more effective tire treatment to improve fuel economy, but this was what I was thinking about. I have no idea whether this is even a sound idea, but it made sense to me. Any response is appreciated. (This was supposed to be for road cars notFSAE cars, that's why it is in the Off Topic forum.)

[MCoach]

The closest thing that I can think of that immediately comes to mind is over-the-road trucks (semi trucks) that have axles that are able to be dropped/lifted for loaded rolling. When they want to maximize fuel economy and in an area with high road limits, such as Michigan, they will raise some of the supporting axles for less drag. On a more related note is that the Hummer has an on board tire inflation system to allow this, although for a different end goal.

[DannytheRadomski]

Upon further research, I found out that rolling resistance tires aren't immensely beneficial, its just a few percent and I think any system like I was describing would outweigh any gain.

[mech5496]

MCoach, the Hummer tire inflation system is tooooo slow for an FSAE car for sure... :P