Cyclocross - Which cross fork?
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10-14-11, 03:06 PM
I've got a Surly Steamroller that I'd like to try in a few cyclocross races. I know it's not the the ideal candidate for CX, but it fits me great and 35's clear (just bought some Kenda Kross Supreme's). Rather than spend $$ on a cross bike, I'd rather go this route and race it for a season to see if I like it.
I'd like to get at least a new front fork for it. I'm wondering if I should go with a Cross Check fork or Long Haul Trucker fork. The CC is 400mm A-C with 44mm rake and the LHT is 390mm with 45mm rake. The Steamroller fork is 375mm, so I'm thinking maybe LHT is better, as it is closer in dimension to the Steamroller fork. The clearance is the same for CC and LHT (both state 45mm clearance).
One advantage I see with the longer CC fork is the BB/crank clearance I'll gain from that. But if it's going to mess up the steering too much, I'd rather avoid that.
What do you think?
Thanks for any input.
Cross Check Fork
I'd go with the LHT, not that I have any particular expertise to draw on. But why do you want to change the fork? Geometry? BB clearance difference is going to be negligible when you consider that you're only lifting the BB a third to a half of what you're adding in fork height.
Also...are you riding the Steamroller as a fixie? It doesn't look like it has any provision for brakes, which seems like it might make a cross race a hairy proposition...
10-17-11, 10:25 AM
A Cross-Check fork works really well on a Steamroller. I've tried it before. Can't speak to the LHT fork though.
10-17-11, 10:35 AM
The differences between the two fork don't amount to much. The 10mm added length with the 44mm offset will provide the same handling and stability as a 390mm length with a 45mm offset. A longer length and a shorter offset cancel each other and the geometry does not change enough to be felt.
The CC fork will raise the headtube buy 10mm, but that’s a small value also.
I'm changing forks on my Some Double Cross. I'm removing a very nice & light Ridley fork and installing a CC fork to improve tire clearance and to have fender and rack attachment points.
If I was racing, I'd look at a lighter Carbon fork. These can be found for about $120.
10-17-11, 12:05 PM
The differences between the two fork don't amount to much. The 10mm added length with the 44mm offset will provide the same handling and stability as a 390mm length with a 45mm offset. A longer length and a shorter offset cancel each other and the geometry does not change enough to be felt..
For every 20mm of fork length, you will make the frame head and seattube angles slacker by 1 degree. The steamroller already has pretty steep angles (at least at larger frame sizes) so making them a bit slacker will probably help for CX. Starting with a 375mm AC fork, the LHT will make your frame 0.75 degree slacker (ie- from 74 degrees to 73.25 degrees) and the CC fork would slacken by 1.25 degrees.
Run your fork trail numbers here, http://yojimg.net/bike/web_tools/trailcalc.php
A slacker head tube angle actually needs more (not less) fork rake in order to maintain the same fork trail measurement. Touring bikes (such as the LHT) often have the rake such that you have fork trail on the low range of acceptable because they are designed to handle better while carrying weight on the front but handle slightly worse when unladen. Starting with a 74 degree frame and adding a LHT for gets you to around 55mm of trail. The CC fork with more height (good mud clearance) and slightly less rake should get you to around 59mm of fork trail. IMHO- the resulting CC fork trail is probably better suited to CX riding and would be the one I would pick. Another side benefit of a taller fork is that it puts the bar/stem a bit higher in relation to the saddle, better handeling for CX rather than such a low road position.
10-18-11, 07:39 AM
I wanted to get a new fork so that I could get more mud clearance with canti brakes. It's also a bit tough trying to squeeze the 35's past the calipers.
Thanks for your help, everyone. I will try the CC fork.
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