Watch it work
Power leaves the rear
Pedal or motor power drives the rear wheel as normal. Internal drive shafts route torque forward through the frame — no chains, no exposed cables, nothing to snag.
The rear breaks loose
In snow, sand, or loose climbs, the rear wheel spins. On any other bike, that’s where forward motion ends. On a CHRISTINI, that’s where AWD engages.
The front pulls you through
Thanks to a slight gearing differential, the front wheel isn’t actively powered on smooth ground — but the moment the rear slips, or the front wheel decelerates against a rock or starts to wash out in a corner, power transfers to the front wheel instantly. When grip returns, it freewheels.
Inside the system
The actual hardware, machined and assembled in Philadelphia: spiral-drive aluminum bevel and pinion gears, an aluminum interlocking clutch, tubular aluminum drive shafts, coated steel universal joints, and stainless sealed cartridge bearings. The front drive runs at a 0.92:1 ratio — slightly slower than the rear wheel — so the freewheel clutch spins passively until the rear slips, and only then does the system engage. That’s why it’s true AWD, engaging exactly when needed. Total system weight: 2.3 lbs. Should the sealed bearings ever need replacing, the entire internal drive disassembles for complete overhaul in under 10 minutes.
The rear spiral gear
The handlebar-controlled “shift on the fly” clutch lives inside the rear spiral gear. Engage it, and the gear interlocks with the rear hub, sending power up the internal shafts.
The head-tube pass-through
Turn the bars and the head-tube gear set is visible through the service port. The CNC-machined head tube doubles as the gearbox itself — a miter gear set lives inside it, with steering forces moved to the outboard cover plate, so there’s no gearing outside the frame.
The telescoping drive shaft
The front drive shaft telescopes with your suspension through a multi-spline shaft — full travel, full drive.
The front spiral gear & freehub
The front spiral gear set drives the CHRISTINI “silent, zero backlash” freehub — you never hear it until the moment it saves you.
The pass-through
A telescoping shaft runs inside the top tube and transfers through the head tube — fully enclosed, nothing to snag.
The front hub clutch
A one-way clutch in the front hub engages the instant the rear slips — and freewheels when grip returns.