Tech News February 4, 2009
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A clever new EBB and lightweight carbon fork from Niner Bikes
By James Huang
Niner Bikes’ new Bio-Centric eccentric
bottom bracket design
Photo ©: Niner Bikes
Big-wheeled mountain bike specialist Niner Bikes is soon to release a
cleverly simple new eccentric bottom bracket design and is also putting
the finishing touches on a lightweight carbon fiber rigid 29" fork.
Niner's new Bio-Centric EBB steps away from traditional wedge-type or
Bushnell-style eccentric designs with a two-piece clamshell layout that
is far simpler in construction. The two halves are inserted into a standard
eccentric bottom bracket shell from either side while a single offset
bolt connecting them nominally maintains alignment between the bottom
bracket cups during adjustment, secures them together, and also pulls
the outer flanges tightly against the ends of the shell to prevent unwanted
Niner says the simple design runs creak-free and eliminates the possibility
of bottom bracket shell ovalization caused by an overtightened conventional
eccentric. Moreover, the full-circumference outer flanges supposedly seal
the shell interior from contamination and the system is also lighter than
usual. As compared to traditional eccentrics - which can weigh upwards
of 300g (even Bushnell's new Featherweight design is still 140g) - the
Bio-Centric is just 117g including its single stainless steel bolt.
Though Niner has obviously designed its system with its own 29" mountain
bike frames in mind, the Bio-Centric can also be used with similarly equipped
26"-wheeled frames or even tandems. According to Niner's Steve Domahidy,
the Bio-Centric has been thoroughly tested in the field and has also passed
the grueling CEN chain torque fatigue test with no issues.
Retail price is also surprisingly reasonable at just US$80.
Niner also has a new all-carbon
29” rigid fork on the way
Photo ©: Niner Bikes
Niner's pending full-carbon rigid 29" fork is still in the development
phase but nearing completion with some impressive early details. According
to Domahidy, the new disc-only fork is "carbon from top to bottom" including
the steerer, crown, legs and even dropouts and final claimed weight is
estimated to be in the neighborhood of 550g.
Stainless steel faces on the forward-facing dropouts will prevent damage
from serrated hub axle ends and quick release skewers, post mount disc
brake tabs will eliminate the need for most caliper adapters, and brake
hose routing will be directly integrated into the left leg.
Despite the feathery weight (roughly 1.2kg lighter than most 29" suspension
forks) Domahidy says the fork has "far exceeded any standard testing parameters"
and the company has thus far conducted over six months of field testing
on various prototypes (we spotted one at the 24 Hours of Moab last year).
"We've gone above and beyond what anybody is doing in a rigid fork for
technology and really use carbon in the way it was intended," said Domahidy.
"[The] super stiff steering precision coupled with the damping characteristics
of carbon make this fork wicked strong but still forgiving for a rigid
fork. The fork blades have been designed to maximize the strength of carbon
while still allowing for that damping quality that carbon is known for."
Pricing is still being finalized but Domahidy estimates that it will
be around US$350.
For a thumbnail gallery of these images, click here