Compact Cranks on Cross bike

[rockdude]

Would compact cranks 50-34, be suitable for cyclocross racing. Looking for a setup that is good for winter road rides and racing next year.

Thanks,
John...

[erikbrooks]

I raced cross 2 years with 36/48. that worked well for me for all but cross. When doing cross I found that the 48 rarely was useful - I spent nearly all my time using the 36, and the little cogs in the back. The result was lots of chain slack, and that resulted in the chain dropping about once per race during remounts. Chain watchers didn't help - those are for dropped chains during shifting, and I had no problems with that. Really smooth technique putting the bike down would also fix this issue.

This year I replaced the 36 with a 42. That's worked perfectly - gives me all the ratios I want, and I've adjusted the chain length to work well with it. No dropped chains. I finish cross this next weekend, and I MAY put the 36 back on.

Swapping one chainring for cross is an easy operation.

Hope this helps.

[bagochips3]

Many people race with 50/34. It'll certainly work. And if you want a bike that works on roads too, it's probably a good choice. I'm building a cross/commute/fire roads bike and am putting a 50/34 on it. I plan to race it eventually, but I'm not going to be in any danger of ending up on any podiums. For serious racing, you probably want different 'rings. 46/36, 46/38, etc seem popular. Depends on the cassette and your riding style, etc. I was looking at the TA Specialties 'rings. They aren't exactly cheap, but you could switch from 50/34 to 46/36 or whatever pretty easily come race time.

[chakatrain]

I race w/my 50/34, but I'm hardly at the caliber of many around here. I also use it for just goofing around offroad, and find the 34 quite useful.

[djg]

I've used it (centaur compact) and haven't had issues dropping the chain. It gives you gears at both ends of the spectrum that aren't terribly useful most of the time, but it also provides what many folks would consider both a decent number of core gears and a better range than they might get with a single. And there are times when I use the easy gears on the sort of rideable run-up climb you get on certain courses. I'm building up a bike right now with a campag 34/48 -- I might switch the inner ring for a 36, but we'll see.

[mtb_frk]

I like a 46/36 setup. The 34 is too small for me, and a 50 is just way too big.

[SpeedyChix]

I run a 34-46 or a 34-48 for CX. Rest of the time I swap out the outer ring to a 50 for the non-CX part of the year.

I'm no powerhouse and like to spin so the 34x27 or 34x25 are nice to have for cx.

If you plan to mostly run inner ring only for cx no reason to mess with your outer ring.

[Spicoli]

Do a 48x38 and leave it on for everything. I've done the 44 big ring ect. and in a race you just wind up using your little ring anyhow 90% of the time. Plus small rings like that suck on the outside since almost all have no pins and shift like crap. You can get a 48 w/pins and run a 38 on the inside. Thats a pretty wide range that works for both road and cross courses.

PS only 130mm spiders are the only ones that make gearing this hard, 110 compact has tons of ring options out there.

[shinomaster]

I think a 34 is too easy. I run a 36/46 with a campy 12-26 in the back and it works well for racing and commuting.

[rockdude]

My best option might be take an old FSA Standard and switch out the big ring for a 46 or 48 and have the standard 39 on the inside. If I need different gearing I put on my 13-29 cassette or my 11-23.

[Marcusaurelius]

I have to second 48/38 combination on a cyclocross bike. I tried a compact 50/34 and found the 34 to be much too low for anything useful.

[xjoex]

I run a 36/42. It is perfect for cross, I never dropped a chain racing on it.

http://i62.photobucket.com/albums/h85/boulderjoe/bikes/100_0572.jpg

-Joe

[ergott]

46/39 up front and 11/18 rear (Ultegra SRAM mix). The 46 has pins. I tried a 38 TA inner and the spacing was wider by 2mm. I had the chain constantly go between the rings when downshifting. I went back to the 39 and went with the SRAM 11/28 from a 12/25. If I can't spin a 39-28 I would have dismounted already.