I apologize for such a n00b question. but i think its fair. I live in chicago and i notice i only use about 3 gears. usually the big chain ring and the big gear on the cog.

i rarely use the small chain ring. any advice?

blast me all you want

It's best not to cross chain (big-big). Try shifting down to the small ring up front and whatever cog in the back that provides a comfortable cadence. It won't make you more efficient but it will give you a little more flexibility in maintaining a comfortable cadence when conditions change due to wind or grade.

The "big-big" combination is considered "cross chaining" and is generally considered to lead to premature wearing out of the drive train.

There is an almost identical gear ratio to "big big" on your smaller chainring, probably somewhere near the middle of the cogset on the back.

I find it helpful to think about your two chainrings as providing you two ranges of gears...low/high...easy/hard...however you want to think of them. If the terrain I'm riding is slightly to moderately uphill, then I spend a lot of time on the smaller chainring, running through the cogs on the back. If things are flat or trending downhill, then it's the big ring.

It would be helpful to know the kind of terrain you ride most frequently and your current setup.

1. It's generally a bad idea to use the big-big and small-small combinations.
2. You have a lot of duplicative ratios between the big and small rings. Try riding small in front and middle in back.

See sheldonbrown.com/gears. For example, let's assume you have a standard double set-up: 53-39 up front and 12-25 in back.

For 700 X 23 / 23-622 tire with 170 mm cranks
With 10-speed 12-13-14-15-16-17-19-21-23-25 Cassette

116.1 85.4
107.1 78.8
99.5 73.2
92.9 68.3
87.1 64.1
81.9 60.3
73.3 53.9
66.3 48.8
60.6 44.6
55.7 41.0

The left column is your big ring, the right is your small ring. See how the big-big is roughly equivalent to the small-middle?

You'll have a better chain line and smaller gaps between the ratios.

What do you mean by "efficient"?

a) Efficient = least power loss through the chain.

You're already doing it by using the largest cogs front and back that give you the gear ratio you want.

b) Efficient = least wear on existing equipment (lowest operating cost).

Use the gears that give you the straightest chainline as described above.

c) Efficient = least wear on equipment and lowest power loss through chain, but willing to buy something new.

Buy a new cassette with a wider gear range that will put those cogs you're using now more in the center of the cassette. This cassette may not exist if you're already on a wide-range cassette. It may be an option if your current cassette is, for example, an 11-23, and you'll probably need a new chain to go with it.

He's in Chicago. Here's the topography: _____________________________________________________________________________________

He still has to climb those freeway overpasses. May want to shift to the smaller chainring for that.