CX v Road frame sizing

ddraver

Hi Guys

I'm looking at getting one of the new fangled On One BishBashBoshes when I get a rebate from the Dutch. I am looking to use it as a winter road/all road/gravel bike and for a bit of CX (however, please do not think I will be challenging the Dutchies for line honours)

at 171mm I am slap bang in the middle of the size small which has a 535mm top tube (the XS has a 515mm). My road bike - which is set up quite aggressively - has a 545 top tube with a 100mm stem. The stock size stem on the On One is 110mm which would make them the same (but with much higher bars). I would likely spec it with the 90mm stem option as I like to keep the handling a bit fun.

So, finally, would you think that a 535mm tube with a 90mm stem will give a good reach for CX riding? I'm a bit confused becasue my MTB is as long as that already so I can't imagine that I need to go 3cm shorter...?

Thanks Guys

LeePaton

I have road CX set up the exact same. Hydro levers give me the extra leverage/grip/height whatever if needed.

The handling differences will be tiny in my experience.

ddraver

Yeah, in the mean time I ve been doing some googling. It seems like the adage about sizing down a CX frame is no longer so important with modern frames (if it was ever true). That's good then...

tgotb

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19738460#p19738460]ddraver[/url] wrote:

Yeah, in the mean time I ve been doing some googling. It seems like the adage about sizing down a CX frame is no longer so important with modern frames (if it was ever true). That's good then...

Yep. I bought my first cross bike a size smaller than my road bike, and with hindsight it was a bit of a disaster. 99% of the time you're sat on the bike in a normal position, pedalling away, just as you would on a road bike. It's handy to have a higher bottom bracket, and the head tube angle will be slightly different, but neither of those have any impact on the frame size.

I heard an argument that going down a size gives you more head tube clearance when standing astride the bike, but that only seems to be a factor if you're relatively small. Some people ride with the saddle half an inch lower, but even that's pretty unnecessary once you get your dismounts/remounts sorted .

ddraver

Yep, I think that was partly becasue the BB was so high (apparenlty that's less common now) and also becasue top tubes could only horizontal, whereas now there are compact frames and all that...

Monty Dog

I run my CX bikes a touch shorter in reach - easier to move weight forward or back as necessary when searching for grip and bigger seatpost setback to allow my quads to drive hard in the gloopy stuff (also good for ripping MTB trails / drop-offs). No need for big saddle to bar drop either - but maybe if you're grovelling in the gutter with a fearsome headwind off the North Sea?