ha ha! thanks for the explanation. I already know I have bad knees and I'm only 25. When I was 16 and working at a grocery store I couldn't squat down very to load the lower shelves... My dad has had fake knees for years and I played a lot of catcher on my baseball teams so I attribute my sucky knees to my father and baseball.

A wuss is the guy that uses the small ring. I have it. But RARELY use it.

Back cogs have a number of cogs. The smallest cog has usually either eleven or twelve cogs. The more cogs, the easier it is to spin it.

The other number is the biggest cog, usually 23 is standard on a double, but sometimes you get a 21 if you want pure power. I've heard but never seen a 19. Climbers for long sustained climbs over hundreds of miles may sometimes want a 25, or 27. They spin easier. I have two 23s, a 25 and a 27. You will need to replace the cog sets every couple thousand miles. Your gears will start to slip as the teeth are worn off.

Oh, they're just talking about the rear cassette (i.e. the cogs in the back). A 12-23 just means the cogs range in size from a small 12-tooth cog to a 23-tooth cog. Obviously, the smaller cog, the faster you can go, but you'll have a hard time going up hills. The larger cog gives you the ability to chug up steeper hills.

On a road bike, a standard double-chainring setup is a 51-tooth big ring and 39-tooth small ring. A compact crankset is 50-34. This gives you a wider range of gear ratios. On a mountain bike, a typical triple chainring is 44-32-22.

For road cassettes, a typical setup is 12-23 (for older bikes like mine that has 8 cogs) or 11-25 (for newer 10-cog setups). Mountain bikes typically run 12-32 or 12-34 cassettes.

Check out http://www.hostelshoppe.com/tech_gearcalc.php to get an idea of the gearing ratios the various chainring/cog combinations can give you.

Pride, don't listen to Arch and Q. Arch couldn't afford all three chainrings, so he had to settle for only 2 of them. If he came up here for a few rides, he'd be begging for a triple, or at the very least a compact double. 39-21 wouldn't get you over a freeway overpass around here. Maybe in the desert, but not in the mountains. Its suicide for the old knees.

Once you go triple, you never go back. 30-25 all the way for me. I have no shame (or knee pain).

Excellent link MTB. I've always wondered how the different gear configurations translated into actual mph. For instance, I am comfortable spinning along at 90-100 rpms. Anything above that and I feel like I lose my pedal stroke. That being said, I seem to max out on a flat road sprint at about 32-34mph. Now I kow why.

Once again, I'm here minding my own business and I get dragged in to the conversation. Whats up with that? ;)

I could never put one on my bike. Many times I wished I had one but I could never do it. Don't those come with a mirror you stick on your helmet.

None of my friends would ever let me live it down, on the road bike, because they all have them for the mountain bikes.

It would be akin to riding a pink bike and advertising for the Gay Pride parade.

ha ha! sounds good.