Thread: 3 or 4 gear cr2
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Old 06-06-2012
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RogerM RogerM is offline
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Join Date: Oct 2007
Location: The middle of off-road nowhere ----- Cheltenham
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I absolutely agree with Wacker on this and it is why I designed Scorpion with an external idler transmission (standard 3 internal gear gearbox + extra idler / 4th gear between pinion and spur).
I found that it made the car FAR more predictable through surface changes and if conditions changed like a downpour.

With the mass of the slipper / layshaft rotating in the the same direction as the rotor, diff/shafts/wheels their is no conflict in torque reaction in the transmission (the two idlers weigh nothing in comparison) and thus the extra consistency.
You would need to change quite a bit of the setup between an internal 4 gear and an internal 3 gear + external idler set up to get the same feeling under acceleration.

Now that said I am not saying the external idler solution is perfect. There are issues regarding covering the idler to keep debris out and I believe that the internal 4 gear might well generate more overall forward drive (for a given setup otherwise). However if like me consistency is the key to good times then I think its hard to beat an internal 3+external idler.
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