Originally Posted by cny-bikeman

We can't tell easily from here what the problem was/is and don't know what he was trying to say, so it may be best to go back and ask for a full but simple explanation of how to use your gears. It's something better explained in person - and best explained by an experienced person riding next to you. That being said here are a few points.

1. The large/large and small/small combinations should be avoided because they stress and prematurely wear the chain if used often, as well as being noisier.
2. Your bike has two or three ranges of gears, one for each chainwheel, but they overlap, so the extreme combinations are not really necessary. Another combination can be found that will feel about the same (and get you going the same speed).
3. It is best both for the bike and you to try to spin your legs around faster than once per second (preferably 70+ rpm) and to avoid real heavy pressure on the pedals. You will actually go faster that way.
4. When you shift you should have light pressure on the pedals.

Here are some pages that may help:
http://www.bicyclenetwork.com.au/gen...-riding/41829/
http://www.intownbicycles.com/how-to...bicycles-gears
http://bicycling.about.com/od/howtor...to_shift_3.htm