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Amsterdam, Netherlands
Welcome to my BLOG about my pasion for retro mountainbikes and everything around that. I love to read your comments in the GUESTBOOK (on the right side) or email me : basads (at) gmail (dot) com thanks for reading, Bas

Monday, 2 November 2009

the Top 10 MIMTBE: Number 8 -> Bontrager

In 1978 Bontrager became attracted to cycling and in 1979 built his first road bike. With his motocross background he was attracted to mountain bike cycling. In 1980 he built his first mountain bike frame and founded Bontrager Cycles in Sunnyvale, California.
In 1984 he cut 700C (ISO 622) 40-hole Mavic MA-2 tandem rims to the circumference of a 26" rim, re-rolling them to create a 32-hole 26" rim.
Bontrager rims were the first lightweight yet strong mountain bike rims, albeit using a profile intended for road racing bicycles. Mavic provided MA-40 MTB rims for some time. Bontrager went on designing lightweight rims, manufactured by Weinmann USA. Several were introduced but never went into high production as the Weinmann plant suffered a fire.
The design of Bontrager frames was based on his studies at the University of California, Santa Cruz and experience as a motocross mechanic. While other manufacturers developed frames out of (oversized) aluminium, titanium, or carbon-fibre, Bontrager's believed steel was not outdated but that its design and production could be improved. Joints could be strengthened by gussets to distribute loads and reduce the weakening of brazing and welding.
He found areas in which joints could be made by bonding and riveting, i.e. the frames made between 1989 and 1994 had cable stops milled out of Aluminum that were bonded and riveted to the top tube. Frames made at Bontrager's Santa Cruz workshop had two-piece seat stays made of larger diameter tubing in the upper area which added torsional stiffness around the brake-bosses, while the smaller tubes in the lower area reduced weight and vertical stiffness of the rear triangle leading to better damping of hits.
Bontrager published articles on bicycle design and construction, ranging from the effects of TIG welding on the tubes to the flaws in the accepted sizing methods of the day.
In 1987 he designed and patented the composite fork crown. This used an aluminum fork crown that clamped the fork blades and the steerer instead of using welds or brazing. This design was used on the Rock Shox RS1 suspension fork, and Bontrager's own rigid fork, the Switchblade.
Bontrager's belief in avoiding heat affection of the tubes led to versions of the Switchblade with bonded and riveted dropouts and brake bosses leading to a fork with no welding or brazing. This retained the strength gained by tempering the tubing.
In 1992 Bontrager Cycles expanded from a one-man shop to a limited production facility. In 1993 they started to produce handlebar stems. In 1995 Bontrager's business partner, Hans Heim, left to join Santa Cruz Cycles, and put his share of Bontrager Cycles up for sale. Trek acquired Bontrager Cycles and hired Bontrager as president.

The current BONTRAGER company can be found here: BONTRAGER COMPONENTS

The top 10 -> MIMTBE


Dan O said...

Those pre-Trek Bontrager frame were super cool. I considered buying one back then - should have.

I work with a guy with a super clean example of one. He commutes daily on it with slicks mounted. Doesn't own a car, rides every day. I mean every single day.

I think if Trek come out with a Bontrager steel hardtail, they would still sell. Not zillions of 'em, but a few for sure.

UsedMountainBike said...

Steel frames still has a following. Causal riders don't know or care. They just want a bike that looks like the one everyone has.