Rear Hub

Assumptions at this point:  (use in bicycle selection criteria in intro)

You have selected a 3-cog pedal sprocket set to reuse that has the following:

1. the largest sprocket has at least 48 teeth 

2. the sprocket set's teeth match the chain you will be using (multiple, identical-size chains will be needed)

3. all 3 cogs are in decent shape with no missing, bent teeth

4. All 3 cogs run true when rotated about the crank bearing. A wobble of more than 1/4" (6mm) is trouble. If the cog/s cannot be trued by bending, choose another sprocket set.

Homemade Tool:  Chain Whip

In order to remove the cogs from a rear hub, you will need a way to apply a large force to hold the largest cog steady while unscrewing the cog that retains the rest of the cog set. A chain whip is used and is diagrammed below (or in Onshape?)

Description

What we want to do is adapt a rear hub from 1 of our used bicycles by reusing the best condition pedal sprocket set from 1 of our bicycles and installing it in place of the existing rear hub cog set of 1 of our bicycles. In other words swap the original smaller cog set on a rear hub with a larger cog set. We will then have a more suitable mechanical advantage/gear ratio for this (heavier than a bicycle) vehicle. 

Pedal Sprocket Set Steps:

1. Remove both pedals and inside crank from the bicycle chosen above. See youtube to help you do this.

2. Drop the chain from the sprocket set.

3. Using a pipe wrench loosen the bottom bracket retaining ring and remove sprocket set + pedal crank from the bottom bracket.  See youtubes on how to do this. 

4. The pressed-on crank remaining on the 3-cog sprocket needs to be removed (usually by drilling out the center of the assembly). The result looks something like this: 

Rear Hub Preparation Steps:

1. Remove...