Gear ratio help

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Old 04-09-2016, 07:50 AM
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Default Gear ratio help

Ok so I'm still at a loss at finding a good gearing for my tamiya dn-01 with the super stock bz motor. I have tried multiple Spurs and pinions with little difference in top end and literally zero difference in acceleration. Now while reading last night I found the BZ motor needs to have a ratio of 9-1 to 11-1. Now my question is using either the stock 79t or 77t option pinion what tooth pinion should I use? I also have 69t spur and 81t spur.
I have 20-25t pinions. In the dn01 manual gearing list it doesn't even have those ratios listed.

Any help in getting this 9-1 to 11-1 ratio is appreciated
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Old 04-09-2016, 06:17 PM
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Final Drive Ratio = transmission ratio x spur/pinion. That model appears to have a 2.6:1 transmission ratio. Rearrange to work backwards.

For a FDR of 9 with your gears for example:

2.6 trans x 79T spur / 9 FDR = 22.8T pinion (23T)
2.6 trans x 77T spur / 9 FDR = 22.2T pinion

Can't quite reach a FDR of 11 with what you have, closest appears to be:

2.6 TR x 81T / 20T = 10.53 FDR

Looks like a 81T and 21T combo would put it right in the middle at just a bit over 10 FDR.
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