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Sep 17, 2003 9:31 AM

I'm new to cyclocross and i was wondering what size frame I should get. I was told that there is a difference between sizing a road bike and a CX bike but I don't know what it is.

My LBS is no help. None of the guys there ride a CX (one thought i was refering to a hybrid!)

I'm 6'1" w/ a 33 1/2" inseam

re: HELP WITH FRAME SIZE....PLEASE!swimbikerunjump
Sep 17, 2003 10:18 AM
I was told to use the same as my road bike (TT bike). I tried the size smaller (just to see) but it was too small. I use 54 for both. I have a 34" inseam but shorter top reach. You would probably need a 56 - and every bike fits different..
Sep 17, 2003 3:52 PM
I am currently selling a bike due to this problem. I bought a Bianchi Axis in the same size as my road bike (58). Top tube is slightly (just a tiny bit)longer, but the top tube is too tall. I am looking into competing, and dismounts aren't happening. As a commuter, PERFECT. As a cross racer, too tall. Its a real shame because I love the bike. When searching for a frame, remember that it will be totally dependent on the manufacturer. Good luck in your search!
Which inseam and what size roadbike.TWD
Sep 17, 2003 4:21 PM
I'm no fit expert, not even close, but I get nervous when people give out their inseam size. Is 33 1/2" your pant leg inseam or your cycling inseam measured from floor to crotch?

I'm just a hare over 6'1", my pant leg inseam is 34, and my cycling inseam is around 36 1/4".

It seems like the old rule of thumb of going one size smaller than your road bike gets tossed around quite a bit, but there are others who profess that you should go the same size as your road bike. I can't comment, as I'm no expert on this subject.

What I can offer, is one data point. I ride a 58 cm cross frame (with slightly sloping top tube), and a 61 cm frame on the road. I've got long legs compared to my torso, so the top tube length was a bigger factor for me. My cross bike has a much longer top tube proportional to seat tube length compared to my road bike.
To get closer to the proper reach, I went with a much smaller frame in terms of seat tube. I have a fair bit more seatpost showing than most folks, but it hasn't given me any troubles with my technique of shouldering the bike.

It seems to me that most folks aim to have their riding position on the cx bike a bit more upright to give you more comfort off-road, and since you don't need quite as much of an aero position off-road. So, that probably means raising their bars, and maybe a slightly shorter top tube.

Without knowing what bike you ride (what size and geometry) how well it fits you, and what cross bike you are buying, it'll be hard to tell what size you need.

Starting with your road bike size, then test riding bikes in that ballpark (same size and maybe 1 size smaller)is at least a starting point. However, since your LBS doesn't stock CX rigs (and doesn't even know what they are) you may need to look elsewhere. Another shop maybe?

I'd also suggest searching back through the archives for fit questions. They come up almost daily.

Now that I'm done rambling.......hopefully someone who knows what the heck they are talking about will come along and give you a better answer than my weak attempt.