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Old 08-20-2008, 06:21 AM   #1
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Default Gearing Guide

540 Silver Can / J-type Motor - FDR of 4.5 (More open sweeping track) - 5 (tighter more technical track), 540 Sports Tuned Tamiya - FDR 5 - 5.5, 27t - FDR 7 - 7.5, B/L 17.5 - FDR 3.5, 13.5 - FDR 4.5, 10.5 - FDR 5.5.

Last edited by auzzy_mate; 10-23-2008 at 12:19 AM.
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Old 10-23-2008, 12:14 AM   #2
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Default Gearing Epiphony

Thanks for all of your tips guys, very helpfull.

Last edited by auzzy_mate; 10-23-2008 at 04:25 AM.
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Old 10-23-2008, 12:30 AM   #3
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IMHO, the Final Drive Ration (FDR) relates the number of rotations the motor needs to move the wheels by 1 rotation. If the FDR is the same, then that necessarily means the for the same speed (assuming same size wheels/tyres, efficiency etc) of the car, the motor is rotating at the same speed.
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Old 10-23-2008, 01:37 AM   #4
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Benjamin, please stop sleeping during school
FDR shows (exactly like stocker here said) how many revs motor has to do for the wheels to make one full turn. To get FDR, you basically have to multiply the spur/pinion ratio with the diff pulley/layshaft pulley ratio (the latter being internal drive ratio).
The only thing different IDR does is it makes the layshaft rotate at different speed for the same car and motor speed.
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Old 10-23-2008, 05:07 PM   #5
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Thanks

Last edited by auzzy_mate; 11-06-2008 at 09:50 PM. Reason: Convinced
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Old 10-23-2008, 05:27 PM   #6
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Quote:
Originally Posted by auzzy_mate View Post
Thankyou, that is my point!

The car with the HIGHER IGR will actually require less RPM, and thus lower temperatures, to get the same FDR/Rollout.

This would allow the car to put in a bigger pinion/smaller spur to make it run higher FDR and make it faster even though the final temperatures are now the same.
No, because Final drive ratio is the FINAL ratio!
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Old 10-23-2008, 09:14 PM   #7
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Quote:
Originally Posted by auzzy_mate View Post
Thankyou, that is my point!

The car with the HIGHER IGR will actually require less RPM, and thus lower temperatures, to get the same FDR/Rollout.

This would allow the car to put in a bigger pinion/smaller spur to make it run higher FDR and make it faster even though the final temperatures are now the same.
Rollout and FDR are not the same for any car with an internal ratio via a transmission. This only applies in a direct drive situation where the spur, axel and wheel all rotate at the same rate.
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