09 May 2008

Lesson Learned: I Hate Math... Gear Ratio Differences Suck

One thing that I noticed very early on is that there is a huge difference between road gearing and mountain gearing. I'm going to do my best in layman's terms to try and describe what it is I'm referring to, Ron is welcome to jump in and help out if he'd like. OK, so my road bike is geared 53x39 in front with a 12-26 9 speed cassette. On the other side of the spectrum my mountain bike is geared 42/32/22 in front and 11-32 8 speed cassette in back. OK, so all these numbers are crazy confusing, right? Layman's terms... the more teeth in the front, the fewer rotations of the crank to turn the back wheel. The fewer teeth in the back the fewer rotations to turn the wheel. So in the big ring in the front, small ring in the back it is more difficult to pedal, but you go faster, with less turning of the crank. Likewise small front big back means your turning the crank over and over and going nowhere. You have to make more rotations on the cranks to turn the wheel which makes it cake to pedal and you move wicked crazy slow. OK, most of you know that, I'm just setting this up for the following.
Now that I have that out of the way, one of the first things I noticed is that in dirt, mud, grassy areas, etc. you are automatically fighting resistance factors to go, let alone to go fast. one thing that is different in the mountain bike world is that you don't always want to be in the big ring. I like to try my best to stay in the big ring on the road unless I'm climbing. On the MTB, the big ring is reserved more for flats, down hills, and to impress those of the opposite sex. Also, when you are on hard pack or roads, its so different than when you're on a road on a road bike. Part of it is the gear difference, but another piece of equipment plays a part in my case. The MTB is a 26" wheel the road bike is a 700x2_c wheels (the blank differing, in my case 700x23c). The difference here is two fold. First you have a far skinnier tire, less resistance. Second it is larger, taller, which means fewer full rotations again covers more distance. I didn't really think about these things going into riding but are finding that they are stark, night and day differences.
Lesson Learned: Physics, math, gear ratio, etc. sucks, but they make cycling a whole lot easier sometimes.

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