The secret is that you have 21 gears, in 3 ranges of 7 gears each. From what I can determine, your low range is 21.4 - 52.0, your middle range is 29.1 - 70.6 and your high range is 36.7 - 89.1. The range is all the gears you can get leaving the chain on one particular front gear. The low range uses the small front chain ring. The high range uses the large front chain ring.
The numbers I am using are are "gear inches". Its an old measurement based on the old "Ordinary" bikes of the 1800's. But it makes it visual. A 21" gear is equivalent to having an old ordinary bicycle with a 21" front wheel. The 89" gear is equivalent to having an old ordinary bicycle with an 89 front wheel. Obviously a 21" wheel would be easier to pedal, but you can't go as fast.
Look at your three ranges. The low range is 21.4 - 52.0. It might seem odd, but your 21.4 gear is when you are on the smallest gear on front and the largest gear on the back. The 52.0 gear is when you are on the smallest gear on front and the smallest gear on the back.
What you may have noticed if you studied the numbers at the beginning of my reply is that the gear ratios overlap between your gear ranges. So some of the gears on the lowest range are higher than some of the gears on higher ranges. Using the small front gear and small back gear in your low range gives you a higher gear than the lowest two gears on your high range with the chain on the large ring in front. So you are already strong enough to be riding in the higher ranges.
Why use the higher ranges? Well, using a small front gear and small back gear tends to bend the chain and sometimes catches the chain on other gears. It's called "cross chain". So bicyclists try to steer toward using the center gears on the back to avoid cross chain.
So, if you are going up a hill in a low gear and get to the top of a hill and want to go into a higher gear, you have two choices. You can shift the front gear for a big step, or shift the back gear up two steps. You use the front gear to select the general range of gears that you are riding in, and use the rear gear to make more subtle choices within the range.
You want to find gears that let you spin easily. I hope this helps.
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"He who serves all, best serves himself" Jack London
Originally Posted by
Bjforrestal
I don't care if you are on a unicycle, as long as you're not using a motor to get places you get props from me. We're here to support each other. Share ideas, and motivate one another to actually keep doing it.
Last edited by Artkansas; 08-27-12 at 06:46 PM.