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gearing question(7 posts)

gearing questionweiwentg
Apr 25, 2002 8:15 PM
what gearing is standard for cross racing bikes, 48-38? and what sort of rear cluster goes on that?
is there a standard?lonefrontranger
Apr 25, 2002 9:28 PM
Oh, wait - we're talking about 'cross here; essentially we all kinda make it up as we go along, right?

I dunno. Hell, even the God of All Things 'Cross Simon Burney waffles on this issue in his book - you can run a triple (and many do) or go single ring with a 42 and chainguards if you really want; cuts down on the complication and anti-shift factor in a muddy or icy race.

Like I said in a couplea threads before, it depends on what your cross races look like. You're in Indy/Illinois, right? The stuff there is all basically grass crits with hurdles and maybe one unrideable nasty runup per lap. I did fine with a 50/38 - 13/26 8-speed in Ohio, and I'm a wimp.

Mind you I had a great "stealth" option on this setup because I used an ancient Coda 110 triple crank with the inner 28 ring left on so as to keep a dropped chain from getting wound round the BB (since my old bike weighed a ton anyhow removing one chainring wasn't going to effect the total significantly) I ran STI, so I could only use the outer 2 rings EXCEPT if I got really knackered and/or stuck with a course that had some kind of non-runnable long sucky climb. It took a bit of coordination but I discovered that I could crank hard on the STI lever whilst pedaling one-legged and kicking the chainrings / crankarm to force the chain to 'drop' onto the inner ring, where it would happily stay until no longer needed. Made a crapload of noise, but I got pretty good at this and used it successfully in a few situations when I was desperate. Funny that it never dropped unless I forced the issue.

Here in CO, I run 46/36 - 12/25 10-speed because there are liable to be grinder-style climbs with loose stuff on them, and other things more resembling MTB short-track courses than any 'cross course I've ever seen. I guess one would use a reasonably standard cassette on the back, maybe more of a touring cassette than a straight block, but I'm sure the guys here will have something more constructive to say...

Hope this helps!
is there a standard?atpjunkie
Apr 26, 2002 10:13 AM
Hell she pretty much nailed it. 48/38 with a 12/25 should be fine for your locale. If it is any steeper you should probably be running. I run a 46/34/34 -12-27 on my "adventure" cross bike as it gets some MTB style duty where I get long grinder climbs (40 minutes) and I'm a Clydesdale. I'm building a race style bike that will be the traditional grass crit gearing. I'll use the "singletracker" as I refer to it as my backup in races and it's also my commuter rig. The gearing may come in handy on some races or if my legs are shot.
re: gearing questionallezjohn
Apr 26, 2002 12:01 PM
I've got a single 44t up front, with 12-25 rear cassette. This does fine for me...I'll add that when road racing, i'm more of a timetrialer than a sprinter...which helps me with the 44t for cross. I also have a 12-27 cassette [used twice, given to me] that I have "just in case" the course/conditions demand it. The single front chainring is so perfect, so simple for cyclocross. Less shifting to think about, therefore you can think about actually racing... Good luck!
single ring for me up front tooclimbo
Apr 26, 2002 12:25 PM
too much shifting focus can be a drain on actually riding my bike properly. I find that over most terrain, getting in the big ring is not that easy, the gear becomes too big to push smoothly. I run a 42 ring and a 12-26 or 12-27 cassette and that does most courses for me on the East Coast. There are usually not that many straight stretches out here to let you get wound up in a big gear.

Of course, if you want to ride your CX bike all the time (road, dirt, trails), a bigger gear spread would be the ticket.
Question for single-ringerspauly
Apr 29, 2002 6:58 AM
Do you use a regular 42 (or 44) chainring on the front, or did you go with something without ramps and pins? Also, what do you suggest for an inner chain guide: a chainring guard where the granny would go (do these exist?); a Third Eye chain watcher; or just the stripped-down front derailer?
Question for single-ringersallezjohn
Apr 29, 2002 12:22 PM
when I first went single ring, I had an old front derailleur, locked into place. But the chainring was just a regular 42, with ramps [no outter chainring guard]. Had problems with the chain jumping off to the outside. Major problems. Cost me a win. I knew before hand that I needed the outter guard. So, after this race with major problems, I went with the full TA setup... guards on both sides, with a 44 non-ramped chainring. Have had absolutely zero problems with it. Its pricey, but worth it. Another solution [I think I saw Marc Gullicson with this] is to use the Spot outter chainring guard, with a Third Eye thingie to watch the inside. I even saw several guys at Nationals with just the Spot outter guard. So, I'm under the impression that generally you have to worry most about the chain falling to the outside... That is with your single chainring mounted on the "inside" position on a road double crankset. Any other single-ringers with comments on this??