Sidewinder Gearing in mm

[FC47]

Sorry, this book fell off my shelf.

There was a thread, searched, discussing what mm pinion ran with what mm spur...

I measured some here, and I think I'm on to it,
but I know there is a simple way to get to the right mm number to size match to get the proper mesh.
Thanks,

Cheers,
Paul

[chrisguyw]

Hi Paul, I will assume that you are talking about store bought motor pods, and since Slot-it is by far the most common of the sidewinder pods, I will again assume that you are talking about Slot-it.

Slot-it sidewinder motor pods are sized (motor centerline to axle centerline) to accept a 6.5mm pinion, and an 18.0mm Spur ..... a simple way to calculate what other potential pinion/spur diameters are possible, is as follows.....

Add the dia. of the stock gears together.......6.5mm + 18.0mm = 24.5mm ,.....Any combination of pinion dia. and Spur dia. that adds to 24.5mm will work perfectly .

Of the gears readily attainable on the market, you could use...a 5.5mm pinion, with a 19.0mm Spur, or , a 7.0mm pinion with a 17.5mm Spur......both add to 24.5 and will mesh just like stock.

Now, you may not find the ratios you are looking for in all these pairings, and , with a 19.0 Spur, you will need slightly taller tires,.......all decisions you need to make.

Cheers
Chris Walker

[FC47]

Chris Thanks man, that turned the light on.
I got my 48 pitch and drag tire math down pat...for first run anyway. Thanks for getting my head back in the game for these.

[Kevan]

I find a rat tail file enables the preferred gear ratio

[chrisguyw]

To a point, you still have the proximity of the rear axle to the can to deal with.

[FC47]

For the big D's I disassemble the motor pod, check everything mating for flash, holes too, reassemble with any gained deflection to favor the mesh...

[Kevan]

Filing/grinding a few tenths of a mm off the can where the axle touches the motor can often makes a world of difference to gearmesh if there's too much backlash.