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| The XF1 |
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.
If the price seems steep, it is.
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| The Brinco |
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 rear-mounted
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.
