powdersummit
New Member
I've been doing some pondering on how to make a friction drive system that would work good for steeper off road conditions and wet conditions using a heavy tread mountain bike tires. I know neither one of these situations are a prime application for a friction drive but the installation is just so darn simple.
Idea 1: Using a larger drive wheel with a "Gear" reduction. The standard spindle size is anywhere from 1" to 1 3/4" from what I can find. My idea is to use a larger spindle somewhere from 3" to 4" but gear things down 2:1 or 3:1 for a slower spindle speed. This would give a larger contact area and lower rotational resistance.
Idea 2: Use a grooved rubber covering on the spindle. Take a look at the coefficient of friction of steel on rubber and rubber on rubber. I can't remember the exact numbers but rubber on rubber is almost twice what steel on rubber is. It is even better than tires on asphalt.
Idea 3: Use 2 driven spindles. By using 2 spindles there would be greater surface contact for better grip on the tire and less chance of slippage. You would link the spindles on a 1:1 belt or chain.
These are just some of the ideas that have been floating around in my head. My ultimate idea is to use all three idea on a single setup to put on a full suspension downhill mountain bike for some really good off road action.
Carl
Idea 1: Using a larger drive wheel with a "Gear" reduction. The standard spindle size is anywhere from 1" to 1 3/4" from what I can find. My idea is to use a larger spindle somewhere from 3" to 4" but gear things down 2:1 or 3:1 for a slower spindle speed. This would give a larger contact area and lower rotational resistance.
Idea 2: Use a grooved rubber covering on the spindle. Take a look at the coefficient of friction of steel on rubber and rubber on rubber. I can't remember the exact numbers but rubber on rubber is almost twice what steel on rubber is. It is even better than tires on asphalt.
Idea 3: Use 2 driven spindles. By using 2 spindles there would be greater surface contact for better grip on the tire and less chance of slippage. You would link the spindles on a 1:1 belt or chain.
These are just some of the ideas that have been floating around in my head. My ultimate idea is to use all three idea on a single setup to put on a full suspension downhill mountain bike for some really good off road action.
Carl