[lincpimp]

Had a look at the kershaw setup. Looks interesting.

Anyone know what size pinion he isusing to interface with the stock baja spur? Something like an 18t mod 1.5? That seems close to stock, IIRC.

Looks like he has a few options on spur sizes for the gear reduction, 40, 45, 50, 54, 60. He is using mod 1 gears by the look of it. So given the use of the 5mm shaft on the 1717 the largest easily obtainable pinion will be a 26t. If you calculate the distance between a 40t spur and 26t pinion, centerline to centerline you get 35mm, which should be enough to clear the 50mm diameter 1717, and the layshaft.

Here is the rc calc with my best guess of an 18t mod 1.5 pinion. Factored that the ratio of 18/57 is 3.166666, and then used the spur/pinion section to calculate the gear reduction section.

Differential Ratio: 1
Transmission Ratio: 2.4000000000000003
Other Ratio: 3.16666
Spur Tooth Count: 40
Pinion Tooth Count: 26
Total Voltage: 22.20
Motor KV: 1580
Tire Diameter (inches): 5.311
Tire Ballooning (inches): 0
Motor Current Draw: 0
Motor Coil Resistance: 0
Spur/Pinion Ratio: 1.54 : 1
Total Ratio: 11.69228 : 1
Tire Circumference (inches): 16.68 inches (423.8 mm)
Rollout: 1.43:1
Total Motor Speed: 35076 RPM
Vehicle Speed: 47.4 mph (76.14 km/h)
Effective KV Value: 1580

Check my numbers and see if that makes sense... Thought the baja 5b tires were taller than 5.3... I just used the numbers in the calc's drop down menu.

If so unless much larger pinions, or more voltage is used this will not be all that fast... I would like to see alot closer to 1:1 ratio on the gear reduction, however going much smaller with the spur will cause issues getting the gears to mesh with the 1717 motor diameter. Unless we can run alot larger mod 1.5 pinion where it meshes with the factory baja spur.