Ok, newbie question here... I ride a mt bike on a cross course at a local park. I stay in my 32 chainring the entire time and use all cogs from 11-32. I ' m building up a cross bike and am having trouble deciding on chainring size. Would like to have a single chainring. Am considering a 34 or 36 tooth chainring as a starter.
I guess my question is how different will a true cross bike feel from my mt bike? While I stay in the 32 chainring on the mt, is there a lot of difference in the 'feel' of a cross bike with narrow tires ? Would I find that a 40 tooth chainring will feel fine with a 9 speed casette?
What I suspect is that I might want the ability to change the chainring depending on the course.
In general something between a 39 and 42 works best for a single ring setup. A 42 will work for most people most of the time. I've paired mine with an 11-28 this year and could not ask for better gearing. For my female clients I've found a 40 works best.
I think you'll find a "real" cross bike a lot faster and not need a 32 so much. I can't imagine using a 32 as even a little ring on a double setup, that's a low gear.
Well Chris you do need to keep in mind that the guy probably has been riding around on MTB tyres, so the 32t isn't quite as small as you think.
I will also add that Betsy has run a 29t on the inner just to be able to climb some steep little pitches in the past, like the grunts at Granogue and such. Other than that she does like to grunt the high ring around...
Personal feeling is that an 11 is about useless, blech. I prefer a 12x27 cause I really dislike big jumps in those clusters. I would prefer a 13xXX even more, but them's too hard to find.
And for the fellow that originally asked, you'll find that the smaller CX tyres are gonna feel a shit-ton different. Put them on a real CX frame and they'll different again.
But you have fun racing, that's the most important thing.
Go with a 42, I used to be kinda fast but now am old and slow and the 42 is still workin. To boot I have campy so don't benefit from running a spread cassette like most of the sram/shimano peeps here (yet).
Could probably go 44 if your fit and run a spread and be just fine. I probably will next year once I make the jump. screw campy
Eric, you could always run Shimergo and take advantage of the Campy levers and the Shimano/Sram cassettes.
Erik, I agree with the guys above. 39-42 work fine, especially when paired with an 11. the sram apex 11-32 is pretty nice on a budget (shimano has options too, but we haven't reviewed them), esp if you do some road and trail rides with the cx bike. you may have chain tension issues though that will require chainguards to prevent the slack chain from jumping off.