Cross Gearing (LONG)

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04-05-2008, 08:49 AM
VeloVT

Cross Gearing (LONG)

I'm thinking of trying a few cross races this year (luckily I have many months to think about this and practice). My commuter bike is a Bianchi Axis, which I think would be fine for my (not very serious) racing purposes. I've been thinking about changing the gearing the bike came with for quite some time, not for potential racing purposes but because it's kind of an awkward set up mechanically (the front shifting has never been great, I get a ton of chain slap as well as super-annoying chain suck, etc...) and from a gearing perspective (wide range, but widely spaced...). Plus I probably haven't used the granny ring in a year and a half...

The bike came with (and currently has) a low-geared triple crankset (48/36/26) and a dinner plate cassette (11/32 -- the bike actually has an XT (mountain bike) rear derailleur to handle the range).

Options I'm considering:
1) 48/38 cross cranks, + maybe reducing the cassette to 12/27
2) 46/36 cross cranks, + definitely reducing the cassette range
3) 50/36 compact road cranks (I think 50/34 will be too gappy for me on the road). Not sure what I'd do with the cassette if I pursued this option.

I'm not looking to make this into a racing-only bike -- I will continue to use it on my commute, so super-super-low gearing options are going to be impractical. I'm a little concerned about the 50/36 option for two reasons -- first, the range is bigger and thus possibly a greater potential for chain drop on a cross course, and second, 50 might be big on a cross course???

As for the other options... I think I wish I could get a 48/36 but they don't seem to exist. I do think I may want to run a tighter-spaced cassette, partly for gearing reasons but partly because the big range right now requires a longish chain, and the chainstays are short on this bike, so I get terrible chain slap (on the chainstays, not the derailleurs) if I'm the 36 ring and say, 12 or 13. (I know this is cross chaining a bit but sometimes it happens, I"m trying to get better about it). I worry that 46 may be too small on the road, but if I'm going to run a smaller cassette, maybe I should have a smaller small chainring (smaller than 38)?

So, those of you who race, what gearing do you run? Any racing I do will be pretty recreational, not super serious, but I don't want to get stuck with gearing that's totally wrong either. And I need to keep in mind commuting needs. Is there a huge difference in feel between 48 and 46?

Any advice is very much appreciated :cool:! I can't seem to wrap my head around this...
04-05-2008, 06:16 PM
Sheesh

First, I don't know a single thing about gearing, but...

On my cross bike, I went with a single ring up front (on the recommendation of the owner of my LBS, who's a phenomenal cross racer) to reduce the risk of dropping a chain while racing. It turns out that this was a GREAT decision because I saw so many people dropping chains! This was my first year racing cross and the only other riding I do is recreational (and, occasionally, commuting).

I started with a 42 in the front, but found it didn't give me a wide enough range to get up the hills (and I'm not a great rider), so I switched to a 38. I found the 38 was so much better and I could get up all the hills with it (keep in mind, I'm in Chicago, which isn't exactly known for hills).

I don't know if that info helps, but... that's my story and I'm sticking to it! :rolleyes:
04-05-2008, 06:17 PM
Sheesh

OH! And, you should totally race Cross! It's a lot of fun, even when it hurts. :D
04-05-2008, 06:41 PM
SheFly

I'm with Sheesh. My race bike has a 42 up front, with a regular MTB cassette on the back. I have raced this all over New England, and never had a problem with the gearing.

My "pit bike" does have a double up front. I have to check with DH on what the gearing is though, and get back to you. I used this bike to race Porky Gulch last year (2 miles up Washington, Storyland crit and a cross race at Great Glen).

And DEFINITELY do some cross! The scene in New England is amazing. Warning: it is addictive :D.

SheFly
04-06-2008, 09:52 AM
madisongrrl

Quote:

Originally Posted by liza

I'm not looking to make this into a racing-only bike -- I will continue to use it on my commute, so super-super-low gearing options are going to be impractical. I'm a little concerned about the 50/36 option for two reasons -- first, the range is bigger and thus possibly a greater potential for chain drop on a cross course, and second, 50 might be big on a cross course???

I worry that 46 may be too small on the road, but if I'm going to run a smaller cassette, maybe I should have a smaller small chainring (smaller than 38)?

So, those of you who race, what gearing do you run? Any racing I do will be pretty recreational, not super serious, but I don't want to get stuck with gearing that's totally wrong either. And I need to keep in mind commuting needs. Is there a huge difference in feel between 48 and 46?
.

I'm a competitive mountain bike racer, but I race a little bit of cross (Cat 3, so I'm not super serious about it like the elite women are, but I'm not recreational either). I additionally use my cross bike to train on in the winter (my road bike is too nice to see the nasty WI road salt).

The 50/36 option is way too much. You would never, ever use the 50 in a cross race. You probably won't need that kind of gearing if you use your cross bike on the road because the wider, knobby, 32mm tires take a little more out of your legs. (I run WTB cross wolfs as I think they are a great all around tire to race on for a variety of conditions).

I run a 36/46 up front and a 10 speed 12-27 in the back (all shimano 105 because it's reliable enough to race with, but easy enough to replace as CX is hard on your components...when I say easy, I mean economically). I rarely use the 46 ring for CX racing. And if I didn't train with my CX bike on the road, I'd probably just go with one ring up front.

You probably won't notice too much between a 46 and a 48 unless you are a big time gear masher (which I'm not, lower gear and a higher cadence suits me). And you won't need that kind of gear to race with. Cross is pretty challenging in that it starts with a field sprint and continues on like a criterium without the benefits from drafting (or at least the the benefits are diminished as compared to a crit).

I think you would be fine to run 46/36 up front. Before you set this gear changing plan into motion, go ahead and visit your LBS. Try out a cross bike that is geared 46/36 and 12-27 and see what you think.
04-06-2008, 05:00 PM
madisongrrl

Quote:

Originally Posted by liza

I do think I may want to run a tighter-spaced cassette, partly for gearing reasons but partly because the big range right now requires a longish chain, and the chainstays are short on this bike, so I get terrible chain slap (on the chainstays, not the derailleurs) if I'm the 36 ring and say, 12 or 13. (I know this is cross chaining a bit but sometimes it happens, I"m trying to get better about it).

Another thing....I do have ultegra shifters on my CX bike. They half-shift which means that I can be in the 36 up front and the 12 in the rear as long as I half-shift the front derallieur. I'm not sure if this is exclusive to ultegra shifters because it's all I've every run on my CX and road bikes. You might have this option also.
04-06-2008, 07:35 PM
VeloVT

Thanks everyone, this is very helpful.

I will have to go think about it some more. I do think I want to stay with a double in front -- if I were making it into just a race bike, I might consider going to a single in front, but I'm not sure I'm ready to do that for it's other life.