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Old 09-04-2010, 10:49 AM
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Espeefan Espeefan is offline
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Default Re: *gear reduction unit

Joe, thanks. I went back and re-did my calculations. I removed the trans cover and counted teeth on the spur gear as well as the belt drive reduction. Here are my findings, assuming I stick with the 3:1 axles.

1st gear final drive ratio is 66.87:1
2nd gear final drive ratio is 33.3:1
3rd gear final drive ratio is 16.65:1

Just for grins, I also calculated the actual mph in each gear. Had to see what kind of ground this truck would cover. One revolution of the tires covers 9" or .75 feet. Running a 6,000 RPM motor, 1st gear is good for .75 mph. 2nd, 1.5 mph. 3rd, 3 mph.

Hub speed is 89 RPM in 1st, 180 RPM in 2nd, and 360 RPM in 3rd.

Looks like a Novak on 12 volts would need a 16:1 planetary and 4:1 Rust axles to come out somewhere between the stock driveline's 2nd and 3rd gear speeds. About 1.8 mph.

Or with a 20:1 planetary and 4:1 axles, I'd be getting about 1.45 mph. A little under 2nd gear speeds.

If I stick with Wedico axles 3:1, a 20:1 planetary will give me about 1.9 mph.
16:1 planetary and 3:1 axles gives about 2.4 mph.

That looks much better!
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Nathan

Last edited by Espeefan; 09-04-2010 at 11:48 AM.
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