Measuring the Bottom Bracket and Spindle

Measuring your bottom bracket and axle correctly is essential for ensuring replacement parts fit your VoltBike perfectly. Most modern e-bikes use metric measurements (millimeters).

Here is the simplest way to get those numbers:

1. Measuring the Bottom Bracket (BB) Shell

The "shell" is the part of the bike frame that the bottom bracket screws into. For acurate measurement remove the crank bolts and crank arms. 

• Width: Measure the width of the frame's bottom bracket shell. Common sizes for e-bikes are 68mm, 73mm, 83mm, or wider "fat bike" sizes like 100mm or 120mm.

• Diameter: While less common to measure by hand, most standard threaded shells are approximately 34.8mm (standard BSA thread).

2. Measuring the Axle (Spindle) Length

If you have a hub motor or a standard square-taper bottom bracket, you’ll need the total spindle length.

• Total Length: Measure the spindle from the very tip of the left side to the very tip of the right side.