These 5 Tips will help you understand the whys and hows of shifting your bicycle:
1. Why so many gears?
|7-speed trigger shifter|
Changing gears on your bikes make the pedals seem easier or harder to turn. There's no "ideal" gear that works all the time, because the right gear at any given moment depends on how fast you're going, whether you're riding on flat ground or going uphill or downhill, the wind, and your fitness level.
If you're pedaling in too easy of a gear, then your legs will get too tired from just spinning and "going nowhere fast." If you're pedaling in too hard of a gear, most of your effort will go into just turning the pedals without making the bike go very fast at all (not to mention the risk of injuring your knees).
Your goal is to shift gears as often as necessary while you're riding to maintain a nice, comfortable pedal stroke. The rate of pedaling is referred to as cadence, and is measured in RPM (revolutions per minute). Most experts say that an ideal cadence is anywhere from 80 to 90 RPM. Think of that as about 1-1/2 complete pedal strokes per second.
Regardless of how many total gears your bike has, when you're riding on flat to gently rolling terrain, you'll usually use only the middle range of gears. If you come to a steep uphill, you'll probably need to use the lowest gears. If you're going down a hill and want to keep putting more effort into going faster, you'll use the highest gears in your range.
2. Working with the front and rear gear combinations
|Crank arms with triple chainrings|
|9-speed rear cog cluster|
Think of your chainrings as BIG changes in how easy or hard it is to pedal, and the rear cogs as SMALL changes. Thus, you'll shift the front chainrings much less often compared to the rear cogs. When you're cruising along on flat or gently-rolling ground, you'll spend most of your time in the middle or largest chainring, while shifting the rear cogs as frequently as needed to account for small changes in the terrain. If you come upon an uphill section of road or trail, you'll switch to the smallest chainring to get the very easy-to-pedal gear to help you spin up the hill.
3. Not all gear combinations are usable
On three-chainring setups, when you're using the middle chainring, you can use the full range of cogs, from the largest to the smallest. However, when you're in the smallest (easiest) chainring, you want to avoid shifting into the smallest (hardest) cog. Likewise, when you're in the largest (hardest) chainring, you want to avoid shifting into the smallest (easiest) cog. These situations are called cross-chaining, and you want to avoid them for two reasons. First, your chain will likely rub on the front derailer. Second, the extreme angle of the chain will cause premature wear and tear on your chain and gears.
This video provides a visual explanation of this principle.
4. Pedal slightly easier while shifting
While you are shifting gears, you must keep pedaling in order for the chain to move from one gear to the next. When you're in a particular gear and pedaling, the chain is pulling on the teeth of that gear. But, for the split second that the chain is moving from one gear to another, the chain is pulling on nothing, or, you might say, it's just pullin on air. So, you don't want to be pedaling with full force while you're shifting, especially if you're pedaling uphill.
It may sound difficult or counter-intuitive at first, but you have to ease up on pedaling ever so slightly while you shift, while still keeping a nice, smooth pedal stroke. With a little practice, it will become second nature. This will help keep your chain from "slipping" while you shift, and from falling completely off your gears.
For this same reason, don't shift both the front (left-hand) and rear (right-hand) gears at the same time! If the chain is only pulling on air on both the front and rear, that increases the likelihood even more of the chain slipping and potentially doing serious damage to your bike.
5. Don't worry about the numbers
|Twist-grip shifter with with 1 through|
8 gear indicator numbers
Have you ever heard this: "Okay, I'm in gear 2 on the left, and in gear 4 on the right, and I have a total of 8 on the right, so that means I'm in gear number 12." Trust us, NOBODY who's an experienced rider or racer thinks about gears in this way. Who likes doing arithmetic, even standing still, let alone when you're trying to enjoy a bike ride?
You should let your shifting be dictated by how you FEEL, not by what number you think you should be in. Your thought process should be something simple, like, "It's too hard to pedal; I should shift into an easier gear." Or, "I'm pedaling way too fast; I should shift into a harder gear."
5 Tips: Climbing Hills
From Bicycling Magazine: The Basics of Bike Shifting