teamtrinity

Hello!

I just got my first cx bike and recently went to a local cx clinic to learn how to mount, dismount, etc.

Anyway...my bike currently has a road compact 50/34 up front. And a 12-27 cassette in the rear. Is this ok? To be honest, I wished I had a larger cog during the cx clinics 40 minute post instructional race! Also...I have a SRAM XX rear derailleur. Should I swap that out for a SRAM road derailleur? Or keep the mountain derailleur on it?

Thanks!

aggiegrads

What you have is fine.

A larger cog in the back would only get used, and you don't want that in a race. If you need lower gearing for the steep stuff, you should probably be running anyway.

A mountain RD will probably be more durable that an RD, so any difference in performance or weight wouldn't be noticeable.

flargle

That gearing is fine. At some point you might want chainrings that are more closely spaced. The hot combo these days is 36/46. 50/34 is such a big jump that it's not terribly usable in a race.

teamtrinity

Gotcha! So you think the SRAM mtb derailleur is fine? Is there any reason to swap out for a road derailleur/

Thanks!

Andy_K 

I've always found that (for me) even 46-36 isn't useful, mostly because I never need the 46. I've gone with a 1x10 setup. I've been using a 36 in front, but I feel like it allows me to be too slow (CX races have a way of moving you into your lowest gear) so I'm swapping in a 38. My biggest concern about 50-34 would be that I'd spend too much time in the 34-27 gear.

flargle

Oh, sure.

marqueemoon

I agree with the above. My lowest gear is 39x25. After that I have to HTFU. There's no sustained climbing in cross. Yes, it hurts on lap 5 but one way or another it's over pretty quickly.

Only bad thing about a MTB rd is it's longer so it can snag on stuff, but it's paid for, so ride it.