Alias530

I just ordered my first CX bike and I'm a little nervous about the stock gearing.

My mountain bike has a 30T chainring and 11-36 cassette (1x10) and my road bike has 34/50 chainrings and a 11-28 cassette (2x11). I'm a little nervous about 36/46 with 11-28 being higher than my road bike climbing gears for more difficult terrain.

I'm thinking about swapping a 34T chainring and 11-32 cassette on there but might need to get a longer cage derailleur for that...

edit: will be used for the more groomed trails in the area, not actual CX racing

gjhsu

I'm on the stock 36/46 and 11-28 cassette. It does pretty well, overall. I don't think I'm missing the 2 extra teeth on the little gear. But then again, I'm not a pro climber by any mean... slow and steady

gamby

I run 50/34 with 11-28 on my roadie and 50/34 with 11-32 on my cross beater. In the cross park where I ride, I spend 90% of my time in the small ring and the 34-32 bailout gear comes in handy on one particular climb I hit. That gear can get you up just about anything.

A good crosser would probably pick up and run up a grade that steep, so the bailout gear might not need to be so drastic. I'm not racing and just ride my local cross park for cold weather outdoor training because it beats being inside on the trainer or freezing to death on the road.

Niloc

You'll be just fine. For actual cyclocross 36-28 is plenty low for your lowest gear. Most racers run a higher lowest gear than that. I'm running 46/36 with a 13-26 cassette. Cylcocross is not that hilly, there are some climbs but they're very short, there's no sustained climbs like on the road where you need to gear down and spin up them. The steepest climbs are called run-ups because you dismount and run up them. If you can't ride it with a 36-28 you should be running it. If anything you have unneeded high gears with your set up. I rarely use my 13 tooth small cog.

For just general trail riding you already have a mountain bike with low gears.

caloso

39x17 or 18

fietsbob

JRA, the crankset is like on my Touring bike , 50,40,24t..

Its not newest cassette stuff so high is 13-50 low is 28-24

Your LBS can change the stock gearing to what ever you want Point of Sale
and offer some Buy back of the stock parts since they are still New , take-offs.

Kopsis

Telling us what you're actually going to do with your CX bike might get you more relevant answers. For actual CX racing you don't need anything lower than 36-28. And, in fact, if you find yourself in that gear, you probably should dismount and run.

Alias530

Will be used on the more groomed trails in the area that my mountain bike is way overkill for, not actual CX racing.

Andy_K 

You can get a 34T chainring to swap in for around $15. I have my cross bike setup 46/34 with a 12-28 cassette. I originally did that for gravel riding and planned to put the 36T back on for CX racing, but instead I left it and have just focused on staying with the big ring whenever I can.

Kopsis

You're generally limited to a 28t cog with standard medium-cage SRAM or Shimano road derailleurs. Some folks report success with bigger cogs, but it's kind of a crap shoot depending on your RD hanger geometry. The 34t chainring swap is low cost with a high probability of success, but it only gets you about 5% on the low-end so I'd make that step 2. Step 1 is to ride it as is and see if you actually have a problem. Remember that upgrading the engine to produce more torque is free (and arguably more satisfying).

Alias530

My crank is FSA something or other in 110BCD, can I just get a Shimano 5800 or 6800 (110BCD 11spd) chainring?

Andy_K 

The newer Shimano cranks are using weird chainrings I think. You can use a Shimano 6750 34T ring: Universal Cycles -- Shimano FC-6750 Ultegra Double Chainrings 10spd

Alias530

Will that work on 11spd?

SlowJoeCrow

I run a 36-46 crank with an 11-28 and I find the 36-28 combo on the road will get me up almost anything I'm willing to climb. I have considered going to a 12-28 cassette because it has less of a jump to the 28T cog but I haven't felt the need for a bigger rear cog.
If you have an FSA crank and want a 34T ring, then the FSA ring Universal Cycles -- FSA Pro Road N10/11 Chainrings is probably a better fit. These are listed as Shimano/Sram 11 speed compatible.
If that isn't enough then yo uwill need a long cage rear derailleur to run a 30 or 32T rear cog or you can go full retro up front with an IRD or Velo-Orange 30-46 Randonneur crank.

Alias530

That's kind of obnoxious how short cage mountain derailleurs can handle 36+ teeth cogs but short cage road can only handle 28? There's not even any Shimano 11spd short cage mountain derailleurs in existence at the moment. I really want short cage and Shimano.

Hdpearson13

I have a shimano shadow zee plus short cage 10 speed with a 11-46 cassette. I run a 42t raceface narrow wide. Only did my first cyclocross race on it the other day and found that dropping chains is something that happens to others and felt the zee shifter made wide range shifts quicker in a area on course that was basically a large dip at bottom of long fast down hill.

thehammerdog

I have a sweet 5 speed. Not sure of the cogs but largest is 23. 42/52 up front....down tube friction shifting.
Bike is a beast

TGT1

Am running a 48/34 and 12-32 10 sp. The stock 36 small ring wasn't quite low enough for some fire roads and the 46 11-32 had annoying jumps at road cruising speeds.

Seems to be about the perfect combination for me anyway. Probably not optimum for racing.

woodcraft

34/46, 12/28, or 11/28 depending on wheels.

I had 11/36 which was great for the long & steep climbs around here, but now relying on the HTFU factor.

fietsbob

These open up possibilities with out a Fixed Bolt circle restriction .. ROAD CRANKS ? White Industries

MileHighMark

My bikes are set up with:

SRAM Rival 22 -- 50/34 & 11-32 (11s)
SRAM CX1 -- 40, 38 & 11-36 (11s)
SRAM Apex/X9 -- 48/34 & 11-36 (10s)

None of the bikes are used for CX racing, though (but all see plenty of dirt & gravel).

09box

I'm riding the stock 7 speed triple crank my bike came with. I can't tell you more than that .

modernjess

48/38 (130 bcd) x 11-26 10 speed. Plenty for my gravel grinding needs. I don't race cross, in fact I don't race period. I mountain bike on my mountain bike or fat bike. No need for a granny.

ksryder

I'm running that exact combo on my steel cyclocross bike I use on gravel. It's fine. I wouldn't mind a couple lower gears and some of the steeper hills but I've never had to get off and walk. I get off road and bushwhack sometimes and I haven't had any troubles.

However, I did look into my options for lower gears. I have a 10-speed with a 105 RD. From what I gather 28t is capacity. Basically I decided if I ever want to go lower I'd get a Deore M591 (non-shadow) RD and an 11-36 cassette. Everything I've read says it will work with road shifters.

I have a BB30 crank, and at 110 BCD I'm limited to a low of 34, but apparently they make adapters for BB30 for all kinds of cranks if I wanted to use a mountain crank.

This is all theoretical, haven't tried any of it.

Alias530

I'm not sure about 10spd but I've read that some people have success using an 11-32 cassette (11spd) with their 105 derailleur with a quoted max of 28T. Shimano downhill derailleurs (Zee & Saint) have quoted max of 36T (for the freeride version) but people say that 40T or even 42T works. I might buy an 11-32 cassette and see if it works, then get a longer cage derailleur if it doesn't. 34x28 works fine for most climbs but sometimes I want lower.