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Turning
Hi. I am back after some time off. This
column will deal with a question that is most frequently asked: why
doesn’t my bike turn well?
The answer is not simple because you may be
experiencing one of two different problems, with multiple potential cures
for each.
First let’s
say your turning problem is that the bike doesn’t turn tight enough – i.e.-
it runs wide in a turn (I refer to this as understeering). Here
are some possible problems and solutions
- The front forks may be too long, causing the rake –
i.e. the angle of the forks – to be too far from vertical. This can
be caused by the fork being too far down in the triple clamps, or by fork
springs that are too stiff.
-
Fork compression dampening may be too stiff or
rebound fork dampening may be too fast or soft, which can cause too
much fork rake.
-
Too much
rear shock race sag or too soft of a rear shock spring can cause too much
fork rake.
-
Rear shock
compression dampening could be too soft or rebound dampening too slow or
hard, which can cause too much fork rake.
-
Tire
selection could also contribute to the problem – a too soft compound tire
on a hard ground track. Different tires, makes, and/or styles may
affect the handling.
- Riding style can cause the bike to run wide – i.e. a
rider sitting too far back on the bike, not powering through a turn,
pulling in the clutch, or having a foot touching the ground. During
a ride, you can’t correct a bike’s setup problem or a tire problem, but
you can make adjustments in your riding style. Possible changes
include moving further forward on the bike and/or getting on the gas to
get the back wheel to step out farther than the front wheel (making the
front of
the bike turn tighter).
The second problem may be that the front end turns too
tight – i.e. tucks in (I refer to this as oversteering). Here are some
possible problems and solutions:
-
The front
forks may be too short, causing the fork rake to be too steep from
vertical. This can be caused by the fork being too far above the top
triple clamp, or by fork springs that are too soft.
-
The fork
compression dampening may be too soft or the fork rebound dampening too
slow or hard, which can cause the fork rake to be too steep.
-
There may
not be enough rear shock race sag. If your rear spring is too stiff,
if your shock compression dampening is too stiff, or if your
rebound dampening is too fast or soft, the back end will be too high,
causing the fork rake to be too steep.
-
Incorrect
tire selection or tire pressure that is too low can cause the front end to
knife or tuck in a turn.
-
Rider
position (too far forward) or too much throttle can also cause the front
end to tuck in.
As you can see, there are many variables and I have not
given you any absolute answers. You have to come up with the best
compromise or balance for your situation. I have had my bike exhibit
all three traits in a single day: it turned perfectly, oversteered, and
understeered. Therefore, I had the perfect balance for the course.
To summarize, you can’t change your setup or tires
during the race, only your riding style. Since the terrain is
constantly changing you will have to look ahead, size up the terrain, and
make adjustments to your riding style to maximize your results. If your bike
turns wide the majority of the time, or tucks the majority of the time, go
back to the section covering your problem and change the setup to achieve
that perfect or near perfect balance.
Until next time, here’s to smooth riding.
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