Quote Originally Posted by DebW
Practicing spinning at 100 or 110 is really good for your legs and will improve your riding. That double shift is not something you want to do constantly, so if your cadence has some flexibility you'll be better off. Besides, I'm betting that you WILL get stronger and can begin spending more time in the larger chainring. Does the 48/21 feel too cross-chained to ride? It shouldn't hurt to at least use it every once in awhile for short periods.
Actually, I usually spin anywhere from 90-105rpm, depending on the surface where I'm riding. I've recently realized that even though my legs can handle the higher rpm, I become fatigued more quickly. I've had asthma issues, so it's a matter of building up my cardiovascular strength. I'm also determined to get my legs even stronger, though, so I can spend more time in the big ring. Funny how you can think you're soooo strong, but then when you learn a bit more about your sport you realize how much room for improvement you really have...

And, yeah, when I look at the 48/21, the chain is at an obvious angle coming out of the bottom of the pulley. I could do it for short stretches, but will probably try to avoid it.

Mimi, cross-chaining is exactly what it sounds like. Try putting your bike into each combination of big ring/rear cog, then look at the chain from the rear of the bike. When you have the chain on, for example, the smallest ring in front and the smallest ring in back, you can see that the chain is angled from front to back, instead of running in a more or less straight line. That's what that experienced rider was telling you, in a not so clear way. It's less stress on your drivetrain to stay in gear combos that keep your chain running as straight as possible instead of at an angle. What's hard is learning a way to know when you're in the proper gear without craning your head down to look at the cogs while you're riding, which will cause you to swerve all over the darned trail...