It’s still a bike but only just
Advances in electric mountain bikes see these hi-tech wheels move closer to mopeds
CAR maker BMW worked with new German e-bike company HNF Heisenberg to produce the XF1, the priciest mountain bike yet to grace these pages.
It does for mountain biking what a Formula One car does for commuting.
Two models of the XF1 are for sale, a 250-Watt, 25 km/h entry level, or a 500-Watt, 45 km/h moped.
Overseas, prices start at about R115 000 (€8 345). If the price seems steep, it is. Spanish motorcycle manufacturer Bultaco’s electric mountain bike, the Brinco, sells for €4 800 and its 2 kW motor makes 60 Nm for truly startling acceleration. It offers a lot of retro glam for a lot less jam.
The pricey XF1 does come with a first, however. BMW said that the XF1 is “the world’s first mid-motor, belt-driven full-suspension e-bike”.
The swing arm allows the drivetrain to move with the rear suspension sub-frame rather than remain secured to the main frame, eliminating recoil from the pedals and enabling a more direct transfer of power.
The motor moves via the pivoting rear swing arm without affecting the tension of the belt drive. This layout eliminates the need for a conventional chain tensioner and lays the path for a mid-motor, carbon belt-driven full-suspension bike.
BMW said in a statement that compared with other rearmounted suspension concepts, which are specifically optimised for muscle-powered drive systems, there is no stiffening of the rear swing arm when the electric motor is providing a high degree of assistance such as during acceleration, constant travel at high speeds or on hills. “The suspension can respond sensitively at any time, ensuring excellent grip and high traction,” said BMW.
The gears and knobs BMW has patented the swing arm design under its i-clean mobility sub-brand.
A mid-mounted Bosch motor with a maintenance-free Gates belt drive gets power from a removable 400 W/h lithium-ion battery pack that is claimed to be good for 130 km per charge. A Rohloff Speedhub 500/14 changes gears and the XF1 rides on Rock Shox suspensions with 150 mm of travel at the rear and a 140 mm fork upfront.
To stop, the bike used Magura MT7 disc brakes. At night, a Busch & Müller Lumotec IQ Avy headlight banishes the darkness.
Instead of a speedometer, an integrated computer monitors the status of the electric drive and provides instant and average measures of speed and distance.
The XF1 from German e-bike company HNF Heisenberg and BMW (left), is almost twice the price of the Brinco, the electric mountain bike from Spanish motorcycle manufacturer Bultaco.