CX Bike Sizing

So I’m almost ready to pull the trigger on this:

But I’m trying to figure out whether to get a 54 or 56cm and the main sizing I have to go off is what I ride in track bikes since that’s all I have. I’m 5’10.

What I’ve found with my track bike setups is I ride comfortable around a 53-55cm c-c seat tube and 55ish cm top tube.

KHS I rode a 53cm: … _Track.pdf

Alien I ride a 55 c-c (57 on the site):

CX Bike geo. has slacker angles (73 ST/72 HT) which I know effects the sizing of what bike I need, but not positive in what way: In addition the 54cm is c-t so it’d be more like a 52 c-c, and the 56 more like a 54c-c.

I donno, ever since high school my head doesn’t deal with numbers as well as some people. Throw me a bone here.

As long as you buy it in white you’ll be fine.

You might want your top tube a bit longer, since your bars will be higher relative to your saddle, probably, closer to level with it. I haven’t checked out the geo of that bike, but that might mean a slightly larger size than you may have bought in other bikes. If you like a 55cm tt on your track bike, a 56cm tt on your cross bike could be about right.

If I was racing cross I think I would want to ride a bit smaller frame as a) the bottom brackets tend to be higher, and b) a smaller bike would be easier to handle and such.

It would be nice if they published the head-tube height as well. But unless it’s shorter on the 54 than say 110 I’m pretty sure you would be much better off on the 54. The slacker headtube will most likely have you running a bit longer stem (or longer reach bars) than on your road bike but that’s much better than trying dismount/remount (or deal with in technical sections) a cross bike that is too big. In many cross bikes you do go a size down from your road bike but in the case of this one they seem pretty true to size.

Keep in mind the 54 being center to top rather than center to center is more a result of the bottom bracket (and thus the entire frame) being higher off the ground than the top tube being shorter. For example, the stand-over of the cross bike you are looking at in 54 is the same as that of a 54cm Cannondale Caad9.


Edit: #protestwordfilters

Braden, thanks man.

I probably should have said earlier but I’ll be racing it cross by next season, but before that I’m going to do road training / possible road racing with it. I’m poor and can’t afford a real road bike yet haha :colbert:

So, steepening the seat tube puts the bars / reach farther away while slackening it brings them closer, meaning that a longer top tube on a slacker frame will fit more closely to a slightly shorter top tube on a steeper frame, yes? That’s what I gather. In that case I’m strongly leaning towards the 56.

For what it’s worth I am 5’10 but with longer than average legs (my saddle height is 75cm from bottom bracket to saddle w/ 172.5 cranks). I ride a 54 Cannondale cross.

Top tube 55
Head angle 72
Seat angle 73.5 (.5 steeper than the motobecane)
head tube 150 (integrated)
stem 130mm

The standover on my bike is higher than on the 54 motobecane but that is largely because the top tube slopes up to what appears to be a taller headtube. You should have no problem standing over the 56 but unless you have much longer arms and torso than I do I really think the 56 is going to feel either too long with a 120-130 stem or you will find yourself running a shorter stem which REALLY does make the steering worse in my opinion.

I should add that if you are using it on the road the shorter headtube of the 54 might work better because it will allow for a lower road like bar position if you need it. I’m not sure what kind of drop you run on your track but I run about 4cm more drop on my road than on my cross.

Hmm. I think below 90 range in stem length, the steering starts to be negatively affected, but right around 100 seems to be a good sweet spot, atleast in my experience / opinion.

Let me know what you think of the bike if/when you get it. I’m considering one in white as a “horray you got a job” present to myself when I get a better job.

For what it’s worth, I’m the same size as you pretty much and I think the 54cm would fit me better.

Word. Will do, just made the order for the 56 in white so I should have it right before Thanksgiving. Hell, I may try to race the last CX race down here in December now…

[quote=“jim”]Let me know what you think of the bike if/when you get it.


im also interested they look pretty sweet. i was thinking of ordering one in the spring

Supplies are limited says BD. That’s why I was getting antsy on getting the thing ordered, didn’t want them to run out of stock in my size or color.