I get a lot of questions about shifting. Gears. How to tell if you’re in the correct gear, how to even shift gears, why you would ever want gears. There are plenty of great reasons to stick to a single-speed bicycle – notwithstanding the ease of maintenance and repair – but if you aspire to climb a hill with some technological savvy on your side, you should learn a little about gears.
Gears were developed for bicycles back in the late 19th century. One way that modern gears change the pedaling pace of a bicycle is through a cable which is attached to a derailleur, a movable piece of equipment that guides the chain up and down a series of sprockets. Bikes can have derailleurs in the front or in the rear.
The easiest gears (lower numbers) are found closest in to the bicycle frame. Without pedaling, you can look at your chain and determine what gear you are in by looking at the location of the chain. In the position furthest away from the bike frame? Hardest gear. In the position closest to the bicycle frame? Easiest gear.
Gears help when ascending or descending by keeping the cadence of the bike spin consistent. If you are in a hard gear going up an incline, you will exert more effort and produce more strain on your knees. Conversely, if you are in an easy gear going downhill, and need to begin pedaling again, you will overspin because the bicycle is going faster than the ideal speed of that easy gear.
You can determine how many gears there are on a bike by looking at the front and rear sprockets and multiplying them together. If there are 3 sprockets in the front and 8 in the rear, there are 24 gears available. Gear ratios repeat, so there aren’t 24 distinctive gears, but rather a range within the combinations of front and rear.
What goes up, must come down
Determining a good starting gear will depend on your terrain and incline (or decline). A good starting gear is usually right in the middle. For example, on a front and rear derailleur system of 2 in the front and 9 in the rear, being in 1-4 is usually a good rear starting gear on a flat surface. Moving along, you will want to upshift in order to maintain proper cadence and resistance. If you max out of your gears at 1-9, should you shift up to 2-9? Well, that will be the hardest gear and unless you are traveling at max speed you will have to exert more effort to keep the cadence going. A better plan is to start middle – 1-4 – then upshift from the front 1 to the front 2. Then, you’re in the middle range of the hard gear, and can go down to 2-3 or 2-2. Anticipating a hill? Always plan to downshift in advance of the climb.
Coming to a stop, remember to DOWNSHIFT TO YOUR STARTING POSITION. Derailleurs that are moved without being in motion will contribute to stress on the chain (chain stretch) which will lead to a decline in performance over time.
In contemporary American bicycles, the left side of the handlebar will have the controls for the front of the bicycle – front brake, front derailleur. The right side of the handlebar will have the controls for the rear – rear brake, rear derailleur. I like to use the mnemonic “right is rear” to help myself remember.
Other resources: the spectacular Sheldon Brown breaks down gear theory; great article on the MSU blog about shifting.