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  1. #1
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    Geometry Advice for Cyclocross build

    I signed up for a frame building class and I've decided to build a steel cross bike. The instructor has a spreadsheet for calculating geometry that uses Paterek's calculations. But you need to enter headtube angle, BB drop, crotch clearance, and inseam.

    I've decided to look at some steel cross bikes on the market to get an idea for geometry. So far I've looked at the IF Planet Cross, Gunnar Crosshairs, and Surly Crosscheck. The Crosscheck, as expect, has a relaxed geometry. I was surprised that the Planet Cross seemed surprisingly relaxed as well. So far I'm leaning towards using the Crosshairs' geometry.

    Any recommendations on geometry? Any other steel cross bikes I can look at for reference?

    Planned riding will be cyclocross races and dirt randonneurs (D2R2).

  2. #2
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    Quote Originally Posted by roburrito View Post
    Planned riding will be cyclocross races and dirt randonneurs (D2R2).
    Don't know what you feel "relaxed" is, but it sounds like you'd be better served by building a road bike with a good amount of tire clearance.
    Last edited by Live Wire; 04-24-12 at 01:46 PM.

  3. #3
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    By relaxed I was referring to lower head-tube angle and wider wheelbase. Closer to a touring bike. I don't think I'm coining any new terms here...

  4. #4
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    HA 72* SA 73*CS 42.5Fork 400/45BBD 70-75

  5. #5
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    Quote Originally Posted by roburrito View Post
    By relaxed I was referring to lower head-tube angle and wider wheelbase. Closer to a touring bike. I don't think I'm coining any new terms here...
    Yeah, I get the term...the is point saying "relaxed" is an entirely subjective term. A 72 HTA is apparently relaxed to you, but average to me. Just trying to get a little context here.
    Still, I stand by my first post- good cross bikes have more in common with road bikes (geometry-wise) than tourers. Shorter wheelbases and snappier handling is the way to go given the parameters you've stated.

  6. #6
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    Richard Sachs has written on this, he has some articles on his site, and maybe his geometry article is there. Actually I think it is an interview in which the subject is covered. I think he says 80mm is the drop. But, it is in the article. Of course just rounding up numbers with no way of knowing how you would react to them if you got a test drive, will sidestep some of the benefits of making your own bike, but whatcha gonna do. Not as though you can go to most neighbourhood stores and get a bunch of test drives.

  7. #7
    Decrepit Member Scooper's Avatar
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    Waterford has sample Cyclocross geometry on its website HERE.
    - Stan

  8. #8
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    Quote Originally Posted by MassiveD View Post
    Not as though you can go to most neighbourhood stores and get a bunch of test drives.
    Not sure if this was being sarcastic or not, but I think the only steel cyclocross bike I could test drive in my area, even though its a major cycling city (Boston), is the Surly Crosscheck. One shop has the Jamis Bosonva but its got a funny geometry (that or they measure differently). It was mentioned that geometry is independent of frame material, which may be true, but I think it would confuse me.

    But this is unlikely to be my last and only frame build! If I don't like the result, I'll just pawn it off on a friend and build a new one. The class isn't one of the hugely expensive professional framebuilder classes, its a at a local artisan co-op that I've taken welding classes at before. I can join the co-op and use their equipment if I want to build more!

    The Waterford geometry measurements, the Gunnar Crosshairs, and the All City Nature Boy are all within 1% of eachother so I think I'll be good going by any of the 3. Thank you all so much, I'll report back after the build (or with more questions during)!

  9. #9
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    Not sarcastic, it will be tough, or would for me be, to get any cockpit time in diverse examples. Just saying there are formulas out there, but I usually let stuff roll around in the brain until I have something in mind that while sensible is also to my specific needs. And then it still needs to go through a few iterations.

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