Re: Gates Timing Belts

Les,

A couple of things to think about:

1. For any synchronous belt drive, each pulley should have at least 6
teeth in mesh with the belt at all times. Any less will reduce the
amount of torque capacity. (ALWAYS Rule #1!).

2. At 4000 rpm, 3mm belts can take about 2.2 horsepower (35 lb-in)
BUT this only applies with wide belts and large pulleys.

3. Belt length is also a factor. Shorter belts can't take as much
torque as longer belts. (Don't ask me why, it seems kind of
unintuitive - but it works).

For your application (keeping in mind I don't know how big your
pulleys are, or centre distance, belt mat'l, etc.), I think you might
be on the edge with a 9mm belt.

The literature from Gates indicates that at 4000 rpm, you can have 300
oz-in torque but you need at least a 98 tooth belt (preferably more)
and your smallest pulley (running at 4000rpm) should be about 36
teeth! (for a 9mm belt).

You could use a 26 tooth pulley with a 15mm belt and have 300 oz-in of
torque as well.

If you are talking to Gates, I would ask to speak to an Applications
Engineer and explain your application - they may be able to suggest a
belt configuration (pulley size, length, width, tensile member) that
will work for you. I've found them to be fairly helpful in the past.
(Also see if you can get free samples if you only need a few belts -
saves lots of hassle)

Note: my calcs are just based on the catalog sizing procedure they
recommend - they may have an alternate recommendation.

Hope this helps

Gary