Cyclocross fork offset and rake

[LouisN]

I just bought a cyclocross frame ...

Now I need to shop for a fork. But I have no idea of what to look for.

I saw some numbers that don't tell me anything, from 47 to 50 offset..., etc...

I'll use the bike mostly as a second bike, commuter, for spring and fall use but mostly on tarmac, and gravel roads.
I'm not planning on doing any real cyclocross racing.

So what should I look for in terms of offset and rake ? What does it change in handling, etc...?

Thanks for the answers,

Louis

[JBV]

The combination of head angle and fork rake comprise "Trail". Trail is basically what makes your bike steer the way it does.

http://en.wikipedia.org/wiki/Bicycle_an ... e_geometry

Steeper head angle and more rake equal faster steering, shallower head angle and less rake equal more stable steering.

Find an online trail calculator, plug in your head angle and the rake(s) of the available forks, and see what works well. You'll probably want something with more trail (i.e. - more stability) for commuting. So aim for something like 6cm of trail. I think anything under about 5.2cm is nearly unrideable at high speeds, 5.5 - 5.6 is a nice sweet spot for road racing, something a bit more stable like 5.7- 5.8 for 'cross racing.

Cyclocross bikes typically have 72 - 72.5' head angles, which result in fairly stable steering when paired with a 43-45mm raked fork. Steeper head angles (73') would typically require a 43mm fork, while really shallow head angles (below 72') can get away with 47-50mm forks, but you get some "wheel flop" at low speeds. That latter combination is typically used on smaller frame sizes to reduce toe overlap, but it's not necessarily ideal for handling.

[LouisN]

Thanks JBV,

Everything I wanted to know is in your post .

Lots of 47-50mm forks available at a good price, but with my 56X54cm frame, I'm pretty positive I wouldn't be a good match now.

Louis