More Than You Ever Wanted to Know About Bikes

I put this in a comment in response to daat y but I assume EVERYONE really wants to know this:

Here we go. Double and Triple refer to the crank gears in the front of the bike (where your pedals are attached). Double means there are two crank gears, triple means there are three.

The numbers mean the number of "teeth" on each gear. On crank gears, the more teeth, the bigger, or harder, the gear. The third gear, the "granny gear", is usually very small, about 30 teeth, and makes climbing hills easier. So, a standard triple might be 53-39-30. A standard double might be 53-39. A standard double is good if you are an animal or you don't expect to climb much.

A 'compact double', what I bought, is a compromise. The bigger gear is smaller than a standard (50 teeth rather than 53) and the smaller gear is smaller than a standard second gear but bigger than a granny gear (34 rather than 39 or 30).

Of course, the crank gears work with the rear cassette. The rear cassette consists of the gears that are connected to the rear wheel. They work in the opposite way from the front gears, meaning that the bigger the rear gear, the easier. In most performance bikes you will have 9 or 10 gears. (My new bike has 10, my Trek has 9).

Rear gears are described by the number of teeth on the smallest gear (the hardest) and the number of teeth on the biggest gear (the easiest). In my case, it is a 12-25.

So, combining my crank gears and my rear cassette, my easiest gear will be 34 in the front and 25 in the back. My hardest gear will be 50 in the front and 12 in the back.

Now, my concern about the lack of a granny gear is this. When climbing the nasty hills of Israel, instead of having an easiest gear of 30-25, I will have an easiest gear of 34-25.

Finally, the bike frame I got is made of titanium, a strong and relatively light metal. I had been strongly thinking about carbon fiber, which is lighter, but based on advice from Psycle Steve and others, decided to go for the stronger if slightly heavier titanium.

The weight is very important, especially when you are as light as I am. To illustrate: If you weigh 200 pounds, and your bike weighs 20 pounds (220) and you upgrade to a bike that weighs 16 pounds, the difference is minimal (about 1.8%). If you weigh 132 and you lose 4 pounds of bike the difference is relativey more important (2.63%). Shlepping as little weight as possible is most important when you are climbing. (Bottom line, it's better to lose ten pounds of fat for free than to lose 4 pounds of bike for an extra $2,000.)

Is this clear?