All-wheel drive specialist Christini has announced a new range of ebikes and, yes, they feature proper two-wheel drive.
Christini has been making AWD bikes for almost two decades (the brand makes motorcycles too) so a move into ebikes was probably inevitable.
The new range includes a 27.5in hardtail and several fat bikes. All are powered by a mid-drive Bafang motor system putting out either 1,000W or 1,500W (claimed) – figures that dwarf those of standard road-legal ebikes sold in Europe.
The AWD system is identical to the one used on Christini’s unpowered bikes, and it’s a fascinating piece of design.
The rear wheel is driven conventionally by the bike’s chain and it sends power to the front wheel via a system of shafts.
On some models, a single shaft runs from the rear dropout and through the left seatstay/top tube, which is a single continuous tube. This drives a short intermediate shaft in the head tube via a bevel gear, which in turn drives a shaft running down one fork leg via a very short chain.
Others work on the same principle, but the main shaft kinks as it passes from seatstay to top tube, with universal joints allowing the change of direction.
The AWD can be turned on and off via a bar-mounted switch and, when it’s switched on, it sounds like it operates somewhat like the systems used in many modern AWD cars, sending drive to the front wheel when it’s needed, much like traction control.
How Christini’s AWD system works
Christini explains its system as follows:
“A handlebar-mounted switch controls the AWD “shift on the fly” clutch. When the clutch is engaged, the rear spiral gear interlocks with the rear hub and power is transferred via internal shafts to the forward spiral gear set, which drives the Christini freehub.
“Due to a slight gearing differential, the front wheel is not actively powered on smooth level ground. However, the moment the rear wheel slips, power is instantaneously transferred to the front wheel. Similarly, the moment that the front wheel decelerates, as in hitting a rock or starting to wash out in a corner, power and traction are transferred to the front wheel.
“The effect is awesome. Instead of stalling when the rear wheel slips – the front wheel hooks up and you keep climbing. Instead of glancing off a slippery root – the Christini AWD tracks right over it. Instead of washing out the front end in an off-camber corner – the front wheel literally chews it’s way through the turn.
“The Christini AWD is simply the best climbing mountain bike on the market with the amazing downhill benefits too. When a front end tucks, the wheel stalls, stops turning, and begins to push. With the AWD system, as soon as the wheel begins to stall, power is delivered to the front wheel, forcing it to turn. With the front wheel under power, it is nearly impossible to wash out the front end.”
If any of that was hard to follow, watch this video for a visual demonstration of the mechanics:
Note that the bikes would be classed as motorcycles in the UK (and, we assume, the rest of Europe) because their power outputs and lack of a speed limiter put them outside the standard ebike category.
This means you’d only be allowed to ride a Christini off-road where motorbikes are permitted, and on-road use would only be possible if you succeeded in jumping through the many hoops to register one as a road vehicle.
Leaving that aside and the fact that it’s debatable whether anyone needs an AWD bicycle, the tech is very intriguing and we’d certainly love to try it out.
Matthew Loveridge (formerly Allen) is an experienced mechanic and an expert on bike tech who appreciates practical, beautifully-engineered things. Originally a roadie, he likes bikes and kit of every stripe, and he's tested a huge variety of both over the years for BikeRadar, Cycling Plus and others. For a long time Matthew's heart belonged to the Scott Addict, but he's currently enjoying Specialized's sublime Roubaix Expert and having a torrid affair with a Giant Trance e-MTB. At 174cm tall and 53kg, he looks like he should be better at cycling than he actually is, and he's ok with that.