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Cyclocross Sizing (Again).....(5 posts)

Cyclocross Sizing (Again).....Steve-O
Dec 7, 2001 5:59 AM
Hey Guys,

I've been riding road and mountain and now I'm planning on adding a Cyclocross bike to the stable. The plan is to use the bike as a commuter, fire road bike, and do several cyclocross races next year.

How do I compare sizes to my road bike. I've heard that you want to go one size down but its the stem length that concerns me. My current measurements are listed below. I am looking at a Kelly Knobby X in the 55cm or 57cm size.

Current road bike (Note - this bike is slightly too long in the top tube/stem)

A) BB center to saddle = 72.4cm
B) BB center to top of seat tube = 58.4cm
C) Center of saddle to center of bars = 71cm
D) Top Tube = 57.1cm
E) Stem Length = 12.5cm

Height = 5' 11"
My Inseam = 33.5"
Weight = 185 lbs.
Riding = Mostly for urban commute and fire roads

Any feedback you could provide would be appreciated.

Happy Holidays,
re: Cyclocross Sizing (Again).....climbo
Dec 7, 2001 6:36 AM
what are the respective TT and standover's on the Knobby Cross? I'd steer you towards the 55 but give us the details on the two sizes. I am 6' 0" and ride a 58cn road frame and a 56cm CX frame. Not easily to compare amongst brands but it looks like the 57 would be too big for you.
Dec 7, 2001 6:58 AM
Thanks for the info... The standover on the 55cm Knobby X is 31-3/8" which seems to fit my inseam measurements. As for the Seat Tube/Top Tube they just list 55 x 55 (I've got an e-mail into them to see if this is actual or virtual)...

I test road a 55cm Bianchi Axis and a 55cm Kona Jake the Snake. Both felt a little cramped but perhaps that's just due to the more upright riding style of a CX bike... I notice that most of the stem lengths on CX bikes look a little shorter then on road bikes. Perhaps this is to keep the weight more over the rear for technical riding?

Steve-O (Just trying to get it right the first time..)
Dec 7, 2001 9:05 AM
the standover on the 55 sounds good to me, if you go up to the 57 your SO gets reduced too much. I run a 12 cm stem on my cross bike, I don't like the short ones. Maybe for off-road general riding those stems are better to sell the bike with but I run slightly shorter than my road stem size (13 or 14) and it works well for me. See if you can have one swapped out for a test ride and feel the difference. It's not a bad idea to be able to get off the saddle a bit easier than a road bike, all that on and off in a cross race and you'll be glad to have that slightly shorter cockpit.
re: Cyclocross Sizing (Again).....Knaster Raster
Dec 8, 2001 1:56 PM
Go for the 55 cm