Cyclocross - Spinning out

My new Rocky Solo CXR comes standard with 12-25 rear and a 36/46 front. I was told by some road riders that when I ride road with them I would easily "spin out" or run out of gears when riding rode. Then I talked to others that said unless you are in real good shape and going down a big hill you won't run out of gears. The LBS I purchased the bike at said they could switch out the front rings for no cost if I wanted before the bike leaves the store. The bike will be here in a few days. So can you spin out that easy with the combination I have going down the road or will I be just spinning out down hills?

Steve

Where are you primarily going to be riding this bike?

A 50 tooth big ring is the standard for compact cranks, 53 for standard cranks.

I find 50 to be a perfect big ring for the road with some bigger tires, with the 46 I think you might run out of gears sooner than you think.

If you will be using this for road and cross both, get the standard set-up and then if you do tend to spin out on the road, and buy a 50 tooth big ring to put on for the summer.

46-12 is at the lower end for a CX bike.

Note that a CX bike has a slightly larger effective wheel diameter than a 700C road bike due to the higher-volume tires though, which will offset lower gearing...but probably just a bit.

If you are considering using the bike on the road a lot, with road tires, I think you will spin out on descents. The question to you is, does that matter?

46x12 @ 110 rpm is 33 mph
46x11 @ 110 rpm is 36 mph

50x12 @ 110 rpm is 36 mph
50x11 @ 110 rpm is 39 mph

If this bike is going to be used for both road and cross but a cassette with an 11 on your road wheels.

Chainrings are pretty inexpensive. I really wouldn't worry about it.

If you every feel spun out, consider yourself lucky, and then purchase a 50t or 53t.

You will find that you can ride on the 46t ring without much shifting to the smaller chainring. The spacing of the gear range is tighter than on a road bike gearing also. The 46t is a usefull chainring.

Thanks for the replies. I can't see myself spinning out if 110 rpm is 33 mph. If the hill is that steep I will take advantage of it and coast :innocent:.

I'd also be careful about swapping out just the chain ring. The chain is supposed to be cut to a length that fits your chainring/cog combos. If they swap the chain ring, they better make sure the existing chain will work, or give you a new chain!

Another option is a 48 big ring. Going to a 48 from a 46 shouldn't require a new chain.

As someone else said, the rings are relatively inexpensive. Your best bet might be to take the bike home with the 46/36 and ride it and see what you think. You can then make adjustments as you think you need to.

One solution I've arrived at is two wheelsets -- one for offroad and one for road. Each wheelset has different cogset gearing setups. Sometimes when I'm using the road wheelset and riding with road riders, I wonder if the 46 is too drastically different from their 52 or 53, but I keep up with them. Plus, we often ride up into the foothills/mountains, and 46 is useful for me there much longer than their big ring.

Another option is a 48 big ring. Going to a 48 from a 46 shouldn't require a new chain.

I've always been a fan of the 48T. Everyone likes to imagine themselves enough of a beast to push a 53/11. Sad truth is very few can. That's why the compact is really gaining ground. A 48/12 gives you a pretty good top end.

I think I will leave it stock for now go from there.

This is a great tool for evaluating your gearing options: http://www.sheldonbrown.com/gears/

Enter your tire size, crank length, 100 cadence under gear units, select your cassette data, and enter different chain ring data. It will provide speed for each sprocket combination. Check for overlap between the larger and smaller chainrings.

Michael

I think I will leave it stock for now go from there.
Good call. Change based on perceived inadequacies, not anticipated ones.