Gear calculator

[Jazzy]

Can some one post a formula to work out gear ratio.
I need the formula rather than the scooterhelp calculator.
Cheers.

[soulsurfer]

This is the best out there...
http://www.tonycassidy.com/Gearbox_Visualiser.html

[carlos fandango]

I'v e been using that for a couple of years and it's excellent:-)
The bit I don't understand is the "red line" ? Is this the rpm when peak power occurs ?

[Muppet]

driven divided by drive x driven divided by drive;
this means clutch sprocket teeth divided by drive sprocket teeth; 47/18=2.61;
gear divided by corresponding main-shaft teeth for any given gear; GP200 forth gear 36/18=2;
from this you get 2.61 x 2 =5.2 overall gear ratio of 5.2 rotations of the crankshaft to 1 rotation of the rear wheel,

muppet,

[Jazzy]

Thanks muppet
That's what I need.

[soulsurfer]

I'v e been using that for a couple of years and it's excellent:-)
The bit I don't understand is the "red line" ? Is this the rpm when peak power occurs ?

It's just passed useable power where there is no usefull gain in power to speed. The good thing about this chart is that you can play around with gearboxes to suit your motor and see the overlap and calculate optimum rpm for gear changes. Unfortunately there aren't many tuned motors out there that give enough overlap using just 4 gears, I would hope the Rimini 5-speed would transform a well set up TS1 into a really tractable motor for touring.

[jonashford]

driven divided by drive x driven divided by drive;
this means clutch sprocket teeth divided by drive sprocket teeth; 47/18=2.61;
gear divided by corresponding main-shaft teeth for any given gear; GP200 forth gear 36/18=2;
from this you get 2.61 x 2 =5.2 overall gear ratio of 5.2 rotations of the crankshaft to 1 rotation of the rear wheel,

muppet,

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