# EV Tire Option



## Tommahawk (Sep 28, 2008)

Their are tires that are more efficient against rolling resistance by design the drawback is the vehicle handling is not as good as normal tread design, you can get away with over inflating a little without too much of a concern. I'm all for wheels that make evs more efficient.


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## TX_Dj (Jul 25, 2008)

As your tire flexes and deforms, it puts a contact patch on the road. The less it flexes and deforms, the less contact patch meets the road. This means the more pressure you run, the less grip you'll get. 

Additionally, the more "solid" the tire is, the less energy it will absorb from a bump, making the tire "bouncier".

If you are in a low-traction condition with a bumpy surface, you will have to actively try to conserve more of your traction.

Without understanding how a tire works, it's easy to get into a "bad situation"... but if you understand how it works and drive appropriately, you will have better safety than if you don't.


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## john818 (Aug 1, 2008)

gmijackso said:


> Another option to this as I see it is to use a run-flat tire. The run flat tires have rigid sidewalls. This is what allows them to run flat, with no air pressure for limited distances. I would think that this would have to be somewhat safer than running a standard tire at higher pressure, as these were already designed this way.


I'm not sure, but I think you're mistaken. As far as I know, at normal pressures or higher, runflats don't have lower rolling resistance than regular tires. Obviously, at very low pressures (or flat) run flats would deform less and roll more easily, but at normal pressures, rolling straight, I don't think it matters much. Oh, and I think your right about runflats being significantly heavier. Increasing rotating weight is bad, but I suppose this is offset a little by not having to have a spare tire.

I wonder how much of the better rolling resistance from increasing tire pressure comes from having a smaller contact patch. Pressure is measured in PSI (pounds per square inch). Correct me if I'm wrong, but if the weight of a car is fixed, increasing tire pressure by 25% should put 25% fewer square inches of rubber on the road, right? And this could be a big factor in lower rolling resistance. I guess this varies at extremely high or low pressure, but is it close at recommended pressures?

Personally, I wouldn't run excessively high pressure in my tires, but I'm more interested in performance and safety than maximizing range. Remember, tires that grip less don't brake as well either. By the way, don't forget that running low pressures can be dangerous, too!


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