yakimatt

I would appreciate suggestions for points to consider on selecting a replacement fork. Currently finishing my second season on a 2004 Litespeed Siena (w/ cane creek integrated). Stock fork lacks sufficient lateral stiffness above 35 mph for this rider's comfort (i.e. confidence). I've logged 2500 miles so far this season, and expect to finish above 3000, my annual average. Mostly weekends with 50 or so mid-week miles all that fits in. Won't be racing. I've just begun looking into it, and want to have some sense of the ways and means of selecting forks before I go to the counter at the local bike shop. I'm probably willing to fork over the $$$ for Easton EC 90 provided I get the right one. Some wookie questions--

Will I be able to install it myself?

What determines the degrees of rake?

What difference does Rake make?

Do I want to git a replacement that has the same rake as the current fork?

Other points or considerations?

Thanks in advance for your help.

blandin

The following was taken from www.sheldonbrown.com:

The "rake" or "offset" of a fork is the distance between the wheel axle and the extension of the steering axis. This may be accomplished by bending the fork blades, or by attaching the fork ends to the front of the blades, or by tilting the blades where they attach to the crown. Rake is one of the three factors that affect the trail of the bicycle, which has a considerable influence on the handling qualities.

Trail is the distance from the contact point of the front wheel with the riding surface to the intersection of the steering axis (head tube) with the surface. The trail is a function of the head angle, the fork rake, and the tire diameter. Trail has a major effect on the handling of a bicycle. More trail increases the bicycle's tendency to steer straight ahead. A bicycle with a largish trail dimension will be very stable, and easy to ride "no hands". A bicycle with a smaller trail dimension will be more maneuverable and responsive.

This was taken from https://www.fitwerx.com:

A fork’s influence on frame geometry is one of the most overlooked, but important items, to consider. Every frame is designed around a specific fork span and rake, which (along with wheel size) effects handling and stability by determining what is called “fork trail”. Fork trail is complicated and requires an article all its own to describe well, so I’ll focus on describing how changes in fork span and rake can directly influence handling.

Span is the distance from the top of the fork crown (where the lower cup of the headset is installed) to where the axle on the front wheel attaches. If you install a fork with a longer span, while keeping the rake constant, you will effectively slacken the frame’s head tube angle. This will tend to make the bike more stable and less reactive. The opposite will happen if you shorten the fork span while keeping rake constant.

Rake is the distance from the bike’s steering axis (an invisible line that follows the frame’s head tube angle down to the ground) measured at a perpendicular out to the wheel’s axle. Rake works counter-intuitively. If rake is the only variable altered, a shorter rake fork will generally make a bike more stable and less reactive, while a fork with a longer rake will make the bike less stable and more reactive.

The best recommendation I can make is, “Unless you are looking to change the stability and handling of your bike, don’t roam much from the span and rake numbers of the fork your frame was designed around.”

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Other things to consider are the crown to axle measurement and stack height if you're going to change out the headset.