CTa

Hey all,

I recently purchased a Soma Rush frame without the fork and plan to put on a carbon fiber fork. The problem is that I can't figure out how to find a fork with the right dimensions. I tried to go with the exact same dimensions as the Soma Rush stock fork (1", rake 38mm, axle-crown-ratio 363mm) but couldn't find a matching one. What's important to me is that the general geometry stays the same (at least toptube parallel to the ground), so I was wondering if there is a way of calculating the angles based on the frame and forks dimensions? Or if not, how can I determine if a fork fits without actually physically installing it? The closest matching fork I found within my budget is the Nashbar carbon road fork with a 43mm rake and axle-crown-ratio of 370mm. Would the increased rake be sufficient to offset the longer axle-crown-ratio?


Thanks!

TejanoTrackie 

A cheap cf fork is not as good as a good steel fork, such as the matching Soma ones. Unless you are willing to pay for a decent quality cf fork, don't bother. Also, the only dimension that is relevant here is the axle to crown length (not ratio). The Soma Rush will work with a rake between 30mm and 41mm.

Also, it appears the Nashbar fork you are interested in has a 1-1/8" steerer tube, so it won't work in the Soma Rush, which requires a 1" fork steerer tube.

MNTC

Any road (700C) fork with appropriate rake will put the top tube close enough to horizontal that you couldn't tell the difference without a level, I'd reckon. Just don't get something with huge clearances or a totally wrong rake and you'll be fine. I second getting a mid-level steel fork over a low-end carbon one.

CTa

Ah yes I meant axle-crown-length of course - I wasn't paying enough attention, thanks for the correction.

To reiterate, the rake does not influence the positioning of the frame in relation to the ground at all as long as its within the 30-41mm-range? So basically I need to look for a fork with a axle-crown-length of 363mm and a rake between 30-41mm?

As for the steerer tube, it comes in both sizes, so that should work out just fine. But I'm open to alternative options, do you know any good cf forks that would fit my requirements? My budget would allow for a maximum of $150 for the fork, although I thought I would get a cheaper one first so I can get to know the bike first, before spending the big money.
Regarding the soma stock fork, I found that there are quite a lot of people complaining about it (misaligned, heavy, too stiff, etc) and its seems way overpriced. The Surly Steamroller fork is only $70 (compared to $120 for the Soma fork) with almost the same specs.

What would be considered a midlevel steel fork, or, in that regard, a decent quality carbon fiber fork? It's my first time shopping for a fork, so I have no idea what to look out for ...

Thanks for the input guys!