Drive Train - Gears, Drum Brake & Belt Drive

The cranks drive chains that drive the Gear Hub, and the the rear wheel through a belt drive. The Gear Hub is located fwd of the read wheel, under the driver's seat, leaving the rear wheel free to be powered by the electric motor(s). Sturmey Archer comes through here again with this cunning hub, the XRD8 - it's an 8-speed gearbox for bicycles - specs. below - I'll get in touch with Sturmey Arthur and start getting quotes on all their great kit - more to come.

The hub comes with a drum brake - seems like a good place to brake the rear wheel - but went with a belt (instead of chain) drive to the rear wheel, hopefully it'll forgive sudden braking ???

There's obviously a few controllers etc. that go with this ... (list coming).

Need to research belt drives & sprockets - I know some of the Harleys have them.

XRD8

Description

• 8 Speed Internal Gear Hub with 70mm Drum Brake

Specs

• Hub Shell Material - A356 Aluminum
• Axle Diameter - 13/32” Slotted
• Axle Length - 185.0mm
• Over Locknut Dimension - 131.0mm
• Right Axle Protrusion Length - 27.0mm
• Left Axle Protrusion Length - 27.0mm
• Spoke Holes - 36
• Pitch Circle Diameter - 89.8mm
• Flange Width - 66.0mm
• Spoke Compatibility - 13g or 14g
• Sprocket Teeth - 23 or 25 tooth
• Chain Line - 45.0mm
• Weight - 1850g

Gear Ratio

• Overall Range - 305%
• Gear 1 - 1.00 (Direct Drive)
• Gear 2 - 1.28 (+28%)
• Gear 3 - 1.45 (+45%)
• Gear 4 - 1.64 (+64%)
• Gear 5 - 1.86 (+86%)
• Gear 6 - 2.10 (+110%)
• Gear 7 - 2.38 (+138%)
• Gear 8 - 3.05 (+205%)