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Old 04-07-2015, 07:51 PM   #48 (permalink)
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Quote:
Originally Posted by Ptero View Post
I entirely disagree. Because there is no neutral with a CVT or CC, a real clutch (as compared to a freewheeling sprag clutch) would require the operater to hold the clutch in for the duration of the glide. As I have pointed out in other posts, the throw-out bearing is sealed, without provision for cooling. It is not designed for long periods of operation, which increases the liklihood if failure.

A sprag clutch, on the other hand, allows instantaneous coasting whenever the throttle is backed off. Obviously, a gentle matching to regain drive force will have to be practiced by the operator to prevent damage to the sprag clutch or stressing of drive components. Still, for hypermiling applications, I can think of nothing better.
I know this is an old thread, but for those who are looking for such a solution (as I am), I plan on getting a new rear rim fabricated that will hold a Stieber ALF2D2 30-500 sprag mounted in the rim.

The ALF2D2 30-500 is a bearing-supported sprag, so the sprag itself rides on roller bearings, allowing one to support the weight of the bike directly on the sprag clutch. If you're planning on doing the same thing, be sure to get a bearing-supported sprag, or it won't work. Non-bearing-supported sprags can't handle much weight.

By using a sprag in the rear wheel, engine braking and drivetrain drag won't slow the bike down when the engine is idled back to coast during pulse and glide.

The ALF2D2 30-500 is plenty stout enough to handle the torque of a scooter engine, and if you've got a more powerful engine, they sell sprag clutches that can handle as much torque as your engine can make.

I just have to find a CNC fabricator who can make a new 12" solid-disc rear rim with the necessary mounting provisions for the sprag. Anyone know of one?
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