User Guide

24
25
At zero tension, a spoke can’t effectively sup-
port the rim.
Bontrager Wheelworks rear wheels employ
OSB (Offset Spoke Bed) rims and special hub
designs with a more inboard left flange spac-
ing. These features provide more equal brac-
ing angles (Fig. W1). Compared to a ‘stan-
dard’ wheel, OSB reduces spoke tension dif-
ference by 30%.
Wheel strength and torque transfer
With a ‘standard’ rear wheel, the left side
spokes are at lower tension than the right
side spokes. At low tension, spokes cannot
apply force to the rim. In a Bontrager rear
wheel, the higher left side tension allows
the left spokes to transfer torque between
the hub and rim. However, it takes more
than just spoke tension to effectively transfer
torque. Bontrager wheels also use specially-
designed hubs (Fig. W2).
The more highly tensioned left spokes
in a Bontrager rear wheel also provide
increased strength through increased radi-
al and lateral load capacity. In other words,
Bontrager Wheelworks wheels are stronger
and more efficient.
Bontrager wheels create a structure with
more even tension, and thereby reduce the
overall stress on the individual components.
The result is that Bontrager Wheelworks
wheels offer unmatched strength and durability.
Bontrager wheels stay true longer
As your bike rolls down the road, the
wheels are loaded with your body weight.
The road resists the force of your body
weight, slightly deflecting the rim at the
point of road contact. As the wheels turn,
the point of contact moves. This moving force
creates a change in spoke tension such that
every spoke on the wheel is seeing a loose-
tight-loose-tight-loose-tight cycle.
The greater the difference in spoke tension
within the wheel, the greater the chance
that the loosest spoke will become slack
and the rim will be allowed to deviate (Fig.
W3). Bontrager wheels have more balanced
spoke tension, or even PST (Paired Spoke
Technology) to combat this effect.
If a spoke becomes slack, additional fatigue
is shifted onto other components in the
wheel. This cycle creates fatigue in the
spokes, which will eventually fail. In the
same way, fatigue can even cause a rim to
fail.
Long before fatigue causes parts to fail, the
wheel may come out of true. As the tension
is removed from a spoke, the nipple can more
easily turn on its threads. This results in the
wheel coming out of true. With Bontrager
Wheelworks wheels, the design creates more
even tensioning. Maintenance is therefore at
a minimum.
The keys to a perfect road wheel
All wheels benefit from low weight, dura-
bility, and low maintenance. Bontrager
Wheelworks road wheels employ a specific set
of features to achieve their high level of perfor-
mance.
Due to the higher average speeds seen
on pavement, the aerodynamics properties
of a road wheel are very important. One
of the major influences on wheel aerody-
Fig. W2
Fig. W3