B
oing... Boing... Boing... If this sounds like an
impression of your bike as you head down
the road then chances are its suspension
could do with tweaking, fettling or even replacing.
The addition of suspension to bikes was one
of the major advances which influenced both
comfort as well as performance. While crude
spring-only suspension started to appear on bikes
before World War I, monoshock suspension with
rising rate linkages as we know them today started
to appear in the 1980s.
As riders we demanded more and more from
our bikes, especially as our skill set improves.
The demands placed on a bike’s suspension are
many. We might want to ride faster, or carry a
pillion and luggage on a leisurely tour of the South
Island. Both of these types of riding require a
different suspension setup to get the most out of
a bike, and the bike’s suspension could probably
do with at least tweaking to get it working well for
the kind of riding you do.
From tweaking the adjusters, starting at the
standard settings, to having them adjusted by a
suspension specialist, through to replacing the
fork internals or even the whole rear shock, there’s
something out there to suit every budget. KR
guides you through the basics.
The front forks on your bike are pretty important.
Not only do they hold the front wheel in place,
semi-isolate you from bumps on the road and
transfer your steering input, they also affect
how your bike feels over bumps, as well as during
cornering, accelerating and braking.
Telescopic-style forks with hydraulic damping
first appeared in the 1930s and 40s, but since
the 1960s the telescopic fork has remained
fundamentally unchanged. Sure, they’ve evolved
massively internally and externally, but they still
provide damping by oil being squeezed through
holes to slow down the movement of the fork.
Ok, not all forks have the same performance,
or even the same adjustment capabilities. A
budget machine might well have no means to
adjust the spring preload or compression and
rebound damping whereas a sportsbike will
likely have all three.
Assuming your particular bike has adjusters on
the forks for spring preload and compression
and/or rebound damping then these are where
to start. The bike’s owner’s manual is the place
to begin and will tell you where the damping
adjusters are and the recommended settings for
each. The first step is to see where your adjusters
are compared to the recommended positions. If
the settings are standard and you aren’t happy
with the ride it gives, you can try tweaking them
to improve the ride. Go one setting at a time
otherwise you won’t know which has made any
difference you feel when riding.
On most bikes, turning the adjusters clockwise
will increase the damping force (slowing down
the movement) and anti-clockwise will decrease
it (speeding things up). The spring preload
adjusts how high the forks sit (static preload), the
rebound damping (sometimes marked with a T
– for Tension) determines how quickly the forks
spring back after being compressed. Compression
damping determines how quickly the forks dive
or compress.
If tweaks to the standard setup (either by you or
somebody who knows what they’re doing) don’t
give you the result you want, then the next steps
would involve upgrading the springs to suit your
weight (which could include a pillion and luggage
if you’re a ‘head away at the weekends’ type), oil
and damping control internals (the shim stacks
on the damping pistons). This all depends on the
results you want to achieve. A simple fork service
(from around $200 - $400) will often put the life
back into a set of forks. Oil in forks is a service item
and needs to be replaced regularly. Not only does
oil provide the damping, it also lubricates the fork
to prevent wear; just like oil in an engine.
For a demanding road rider, or for serious
track use, then something like replacement
fork internals can offer a big improvement in
performance. Prices start around $330 for new
damping pistons through $1400 for a full road-
level cartridge kit – fitting is on top of that.
KIWI RIDER 61