Quote:
Originally Posted by asid61
You can make a 1 stage shifter f you use 4 inch wheels and can machine a couple gears down to length.
Basically, have an 11t pinion and a 14t pinion on each CIM shaft and have them gear to two gears- a high speed and low speed gear. Then shift between the two gears.
That's a single stage version, but you can only get a spread of around 1.4x due to the maximum size of the gear being limited to the size of the wheel. Adding a second stage would allow you to have massive spreads.
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I'm not sure that's really ideal. With an 11:76 in low gear and a 14:74 reduction in high gear, (same C-C distance with vex pinions), you get a 1.31 spread. On a 4 inch wheel (the gears have an OD of 3.9", so that's the smallest wheel you can get), you'll see free speeds of 13.4 and 17.5 fps, both of which will have you tripping breakers with 2 or 3 CIMs per gearbox.
You'd also need to find 76 and 74 tooth gears, and put in the hole for the bushing and the circular grooves for the ball shifter components.