Fritz said:
I have an old Trek 930 (1998 or so) with a worn out Rockshock on it.
The suspension doesn't really hold my weight and is kind of clunky.
So I decided to buy a rigid fork for it. I shopped around and found
one on ebay for very little money. A double drive fork that
probably is not suspension corrected.
My question is.... What kind of surprises am I going to encounter
when I change this fork out (handling wise)?
Keep in mind that I ride mostly on the road or easy off road stuff.
With a shorter fork, the front ent of your bike will ride lower, and
this has a few different effects that are neither intrinsically good
nor intrinsically bad.
The head angle will become steeper, and this shortens the bike's
natural trail. Between the lessened center-finding bias in the
steering system and the lessened effort required to turn the front end
at speed, you may find your bike feels more responsive.
Correspondingly, you might find it feels annoyingly twitchy.
The change in steering behavior you observe will be related to the
amount of angular change between your bike on its new fork and your
bike on its old fork in the statically sagged position. Swapping out a
soft 60mm travel fork on a bike with a 70.5 degree head angle is very
different than swapping out a firm 80mm fork on a bike with a 72 degree
head angle. If you do find the bike twitchy after retrofitting it,
keeping a relatively heavy tire on the front can help stabilize it.
Your bike will feel less "stuck" to the ground on rough surfaces at
higher speeds, because the rigid fork will not allow the tire to follow
the contour of the ground as closely as before. This will almost
certainly have more effect on feel than on actual control in most
circumstances. A front-heavy weight bias tends to make you more aware
of the bike's steering qualities, as well as exaggerating trail- and
contact-patch-related effects.
The bottom bracket will drop, causing the bike to be marginally quicker
in transitioning through varying lean angles. It will also reduce the
lean angle (with respect to vertical) at which your inside pedal will
touch down.
The seat angle will steepen and the handlebars will drop, placing you
in a lower riding position and putting more of your weight on the bars
rather than the saddle. You will probably be more aerodynamically
efficient in this position, but you might find it less comfortable.
You'll find that bumps and shocks become more pronounced even at the
rear, because front suspension plays a role in attenuating rear wheel
shocks too. So you'll probably ride "on your toes" more than before.
Unless the head angle of your bike is too steep to cope with these
changes gracefully, you should find that your overall experience
becomes more road-bike-like. This might make you want to mount narrow
slick tires, but you should probably stick to fat tires, even if they
are slicks. Shorter tires will further lower your bottom bracket and
that might make the difference between a bike that's easy to live with
and one that's peculiar. In my subjective experience, the bottom
bracket height below which a bike becomes annoying (with 170mm cranks)
is about 10.5".
Chalo Colina
