Old 06-27-07, 07:02 PM
  #9  
Lowell_
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Join Date: Jun 2007
Location: Vancouver, BC
Posts: 273

Bikes: Rocky Mountain electric bike

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Originally Posted by Lock
Actually, rolling resistance is a *huge* issue for battery-electric vehicles... because of the tiny (compared to a gas tank) amount of energy EVs have to work with. This is no diff than any higher-end pedal bike, where someone used to a "clunker" hops on and realizes how much easier the high-end machine is to pedal... Low rolling resistance, aerodynamics, and lowest friction is all mechanical systems actually *consume* the thoughts of EVers...

tks

Lock
human-electric hybrid pedestrian
http://www.sheldonbrown.com/tires.html

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The higher the air pressure, the less the tire will deflect.
The trade-off with this is that if you pump the tire up too hard, you lose the benefits of pneumatic tires: the ride becomes excessively harsh, and traction will be reduced. In addition, extremely high pressures require a stronger (heavier) fabric and stronger (heavier) rim flanges.

Rolling resistance does decrease theoretically with any increase in pressure, but with modern, high-quality tires the rolling resistance at correct inflation pressure is already so low that the infinitesimal reductions gained are more than outweighed by the trade-offs.

An overinflated tire will have slightly less rolling resistance.
An overinflated tire is more prone to damage from sharp rocks and similar road hazards.
An overinflated tire will give a harsh ride on anything but the smoothest pavement.
An overinflated tire can bounce on surface roughnesses. This can cause dangerous interruptions in traction, particularly if it happens during cornering.
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