tiras25

Hi guys,

Are the measurements the same when selecting a road bicycle vs. cyclocross? So if I ride 61cm frame road bike. Do I need the same for the cyclocross?
I know the mountain bikes are totally different. Not sure about the cyclocross.

Thanks.

bleui

if I'm not mistaken, you need to choose one size down on the CX frame

Ben I.

No expert, but I think you can do about the same frame size as a road bike. The geometry of cyclocross bikes is just different to allow for the different riding style.

dtrain

Kinda depends on your body type and preferences. 'cross bikes have a higher BB (makes sense for clearance). So the 'same frame size' would tend to result in a taller standover clearance. Top tubes, though, tend to be a bit shorter on 'cross bikes of the 'same frame size'...which is more important to some.

headloss 

It depends on the cross bike. Look at the effective top tube rather than the frame "size." Also look at bottom bracket height. A cross bike with a higher bottom bracket (60mm bottom bracket drop, for example) would require sizing down; I have to size down for Ridley and Cannondale. Other cross bikes have a 70mm bb drop and basically fit the same way (all else equal) as a similar road bike (Focus, until recently used a 70mm drop but now is something like 65mm). Look at specific brands, and don't make general assumptions lumping all cross bikes together.

CharlyAlfaRomeo

Find out the reach and stack of your road bike and find a 'cross frame as close as possible to that.

gamby

Bigger tires on the cross bike will create a taller standover height, plus, you'll want a little extra clearance in the top tube.

You might also find yourself going with a stem that's 10mm shorter than you run on your roadie.

topflightpro

Cross bikes tend to size down a bit. So, while a 56 road frame might have a 56 top tube, a 56 cross frame is more likely to have a 58 top tube. You would need to go to a 54 cross bike to get that same 56 top tube length. You will want bikes with similar top tube lengths.

I ride a 56 in most road frames and have a 52 cross bike. I probably should go up one size in my cross frame, but I don't race enough to justify the expense.

woodcraft

I have a Tarmac, & Crux.

The Crux has shorter top tube, higher stand-over (but same BB drop), & longer Wheelbase relative to the Tarmac, for the same nominal frame size.

woodcraft

Since an aero position is less important for CX, a good fit will tend to have shorter reach, & higher stack.

CharlyAlfaRomeo

Aerodynamics are just as important in CX IMO.

In a CX race you spend next to no time in another rider's draft so even though the speeds are slower the fact is that aero matters a lot.

If it didn't the bikes wouldn't have drop bars and the riders on the World Cup circuit would be sitting more upright, but they aren't. Flat backs abound.

Getting a CX frame with a similar reach and stack to your road bike will get you really close to a good fit, a stem and a couple of spacers should be all that's needed to really dial in the fit from there.

macca33

I ride 58cm CAAD10s and an XL (58cm) Focus Mares CX - their 'fit' is almost exactly the same.

I considered dropping down one size when buying the Focus frameset, but looked at the geometry and realised it was unnecessary.

A good check of the geometry would be the first thing to do.

cheers