Hello everyone , this is my first year in cyclocross but not racing ( MTB). I have been experimenting with different gears ratios . Recently my bike came back from the bike shop and the mechanic installed a 10 cog road set on the back coupled with the two on the front crankset. It almost tore my leg off in the mud and climbing . I figure that there must be an easier combination to ride effectively on the grass and through the mud.
Any suggestions on how I can approach figuring out the right combination for my racing?
Do you know what the cassette and chainrings on the front are - i.e. how many teeth on the chanrings and what the smallest and largest sprockets on the cassette are? Having that info would give people a good starting point for advice.
It sounds like you may need some smaller chainrings though...
Yeah, smaller chainrings are probably what's in store for you. If he installed a traditional road chainset in the front (53/39) you may be fine with just using the 39 only and not splurging for a new crankset/rings. Depends on what your budget is. I use a 46/36 with an 11-27 cassette in the back, but that's what my bike came with, so I'm leaving it until I get some dough to change it around.
Also, consider your crankset bolt circle diameter (BCD). If you've got a 130mm BCD standard crankset, you'll be limited to a 38t small ring. If you've already got a compact (110mm BCD) crankset, you'll have a lot more options.
110mm BCD (Traditional MTB Standard and new Road Compact Standard) will accept a minimum of a 34T ring. 50T is about the largest big ring that you'd want to use, but for 'cross, I'd recommend a 44T, 46T or 48T.
Having been away from racing and serious training for several years, I'm running an old MTB crankset (110mm BCD) with a 34T single + a chain guard (cut from a 46T ring). I have precious few times when I run out of gears on the high end. I'd anticipate upping it to a 36T or 38T in coming years assuming that my fitness and strength improves.
I would politely disagree that 46s are only for pros. I have a 39/48 on one of my bikes, and do use the 48 and I'm not very fast. On one 9s bike, I have a 13-26 cassette which works really well for cx, and if it was 10s, it'd just add a 12 which I prob wouldn't use off-road anyway. I don't use the 13 often, and wouldn't use a 12, but do find the bigger ring useful, esp for riding on the road to the trail, or using slicks with an 11t for early-season group road riding on the cx bike.
don't forget that we're not constrained to 11+ or 12+ cassettes, even for 10 speed. juniors need a way around this too for gear restrictions. You can always try one of these that start with a 13,14,15, or even a 16t! Can you image a 16-27? you could use one of those blow-out 39-52 or 42/52 cranksets and still have a lower high gear than a 42/12. crazy.
Junior 10s shimano cassettes: Shimano Ultegra 10 Speed Road Bicycle Cassette - Junior Development...