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  1. #1
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    Cyclocross sizing

    I'm looking into cross and having a hard time deciding between a 54 and 56 frame sizes. I ride a large SC LT Blur that I love and usually when I get on a med frame I am glad that I ride a large. I am 5'10 and a 32 inseam. Any insights out there?

  2. #2
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    54 seems a tad small for your size. I''m 5'11" with a 32.5" inseam, I ride a 58cm frame with a 58cm top tube and that's perfect for me.

    I think that top tube length is the more important value of the two though so maybe base your decision on that rather than seat tube length.

  3. #3
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    I have found that CX bikes will have pretty tight SO compared to their MTB counterparts, probably closer to roadish SO. I have a Salsa roadie that has a 51cm TT and my AC is actually a 52cm TT(even though the size is listed at a 46cm frame). The SO for both is right at 29" and I have an inseam of 29". Closer than I would prefer for SO I am used to in MTB geo but anything smaller and the cockpit would feel tiny and cramped for the kindof riding it is intended for.
    I agree with Hogdog.
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  4. #4
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    My old Lemond book with sizing chart appendixB says 52.8cm frame for a 32" actual inseam (28.3" from center of bb to top of saddle, the Ned book agrees with that bb to saddle top measurement).

    You are measuring actual barefoot inseam?, not pantsize, right?

    I ride same size road frame and cx frame, but: I have a sloping top tube frame (specialized tricross) that gives slightly higher handlebars than a horizontal top tube bike, and I find it to be very comfortable at speed in the rougher stuff.
    You will find you standover very little on a cx bike, -just at the start line, all your mounts and dismounts are to the side. So long as you have a standover gap, even if small, I wouldn't worry much about standover.

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    you really need to know what top tube size is a proper fit for you on a road bike. Thats the size you need to go with...

    you'll hear 2 schools of thought; some people will 'size down' for a cross bike. I dont know why. Some cross bikes (like my Ridley X-fire) will have tall bottom brackets (for clearance), tall seat tubes (easier shouldering) and tall head tubes. Like mentioned, this reduces your standover clearance. Which means very little. My nuts rest on my tob tube while standing and its not been an issue.

  6. #6
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    Thanks for all the great advice! I'll be letting you know how it works out!

  7. #7
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    I don't know if this help, but the distance from my seatpost clamp to bars is about the same on both my cx bike and my xc bike, I reach further forward on the cx bike but the hoods are narrower than the grips on the xc bike. Can you take the dimensions of your xc bike with you when you go shopping?

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    Quote Originally Posted by hammy56 View Post
    you really need to know what top tube size is a proper fit for you on a road bike. Thats the size you need to go with...Like mentioned, this reduces your standover clearance. Which means very little. My nuts rest on my tob tube while standing and its not been an issue.
    I have no idea why people are always hung up on stand over height. Go with a proper ETT fit and you'll be happy. Unless you like straddling your TT a lot.

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    Quote Originally Posted by jimPacNW View Post
    I don't know if this help, but the distance from my seatpost clamp to bars is about the same on both my cx bike and my xc bike, I reach further forward on the cx bike but the hoods are narrower than the grips on the xc bike. Can you take the dimensions of your xc bike with you when you go shopping?
    I havent compared my xc and cx fits...but my reach is shorter on the cx bike than the road bike. By maybe a full cm. I think the last thing you want is to be stretched out when trying to re-mount...And I dont see any advantage in much of an aero position in cx. Speeds are relatively low...
    Quote Originally Posted by phsycle View Post
    I have no idea why people are always hung up on stand over height. Go with a proper ETT fit and you'll be happy. Unless you like straddling your TT a lot.
    yep.

  10. #10
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    OP, do you have a road bike to compare to? My fits are near-identical between 'cross and road - I really just change the amount of drop to the bars.

    Between XC and 'cross, I ride a 18" mountain bike and a 52cm 'cross bike. ('13 Kona Hei Hei and '09 Kona Jake.)

    Hope that helps.
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  11. #11
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    I ride a 56cm Super Six, and I just ordered a 54cm CAADX today. Cross Bikes run big I guess, because the 54cm CAADX fits perfect, like my 56cm SuperSix.
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  12. #12
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    I am your size and ride a 56.
    Perfect size for me.
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  13. #13
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    I always wondered about proper fit on cyclocross, I once heard you should go with a slightly shorter top tube in cross over road. I'm 6', 33" inseam, ride a 56 cm cannondale super six with a 120 mm stem, been riding the same dimensions for years(5th cannondale) should I go with a smaller frame or a 56 with a shorter stem?
    BTW, I've been fit onto the 56cm, tried a 58, but the 56 always felt better, I tend to run my saddle lower than what some would recommend, 29.5" center of bb to top of saddle, totally works for me, have tried lower and higher, after 30+ years of riding/ racing, don't think I'll change much.

  14. #14
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    Re: Cyclocross sizing

    I switched my 'cross bike to road duty a while ago. I initially went up a stem size and lowered it a spacer or so. Ended up switching back to the same stem I'd been using for 'cross, but keeping the extra drop.

    So I could see going either way. If the 54 has more than a 10 mm difference, though, maybe stick with the 56.
    "Don't buy upgrades; ride up grades." -Eddy Merckx

  15. #15
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    I'm also 5'10" with 32 inch inseam.

    I've gone with slightly smaller sizes: 54cm Ridley X-Fire. Now currently on a Medium Giant TCX (52.5). I ran 100mm stem on the ridley and currently 110 on the Giant.

    The general rules I've read says the CX handlebar setup should be 1-2 cm closer and/or 1-2 cm higher than your road bike setup. While also rotating the handlebar up a bit.

    I've read that Adam Myerson, who is 5'10", runs a 52cm Ridley with a super long stem (130mm?). I imagine he likes more weight on the front wheel.

    EDIT: another thing I like about a smaller frame is that you have more seatpost exposed to clamp bike onto bike stand. With the bigger ridley (and how these CX bikes have high top tubes, for easier shouldering) I had little seatpost exposed. It will depend how long your legs are and how comfortable you are with a high seat height. I raced with a lower seat height to get less pounding on the butt; it rode lots more comfortable and didn't tire my low back as much. Some trial and error definitely involved with seat height, which I adjust by race course.
    Last edited by Poncharelli; 01-09-2014 at 02:20 PM.
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  16. #16
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    How did you like your 54 x-fire from the sizing perspective? I am your same height just with 33" inseam.

  17. #17
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    Probably not what you want to hear but you gotta test ride before you buy. I road 14 different CX bikes and fit anywhere from a 55cm to a 57cm depending on the manufacturer
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  18. #18
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    absolutely agree. Just don't have many options to try before I buy where I live. (brasil)

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