Shifting on a bike may be confusing to those who are used to driving in a car. With a manual transmission, you'd start off in 1st gear and increase as you go faster. In cycling it doesn’t work that way, you may ride a 24 speed that means you have 24 different gear combinations. You shift according to how your body feels.
The purpose of shifting is to keep your pedaling at a steady pace, called "cadence" which is the number of times one foot goes around in a minute, as described in our pedaling tips page. You should shift gears every time you feel your legs starting to strain or spin too quickly. This most often happens as terrain changes, as you begin to climb a hill you may need to shift to an easier gear. As you go down a hill, you may need to shift into a harder gear. Use a gear that feels like your keeping a good pace. If you ride in an area with a lot of hills, you may be changing gears a lot to keep yourself comfortable.
You cannot shift a stopped bike, you must pedal in order to shift. It's also important to ease the pressure of your pedaling during the gear changing. This makes the shift smoother and prevents possible drive train glitches. As terrain changes, prepare for the steep parts by shifting into an easier gear before you’re on the steeps.
Shift levers are located on the handlebar usually between the grip and the brake lever. Shifting is accomplished as you are pedaling by moving the shift levers, some are pushed, others are pulled or twisted as part of your grip.
Shifting will make pedaling either easier or harder. Right handed shifting makes small differences in pedaling effort. Shifting the right handed lever moves the chain across the gears on the rear wheel. The larger the cog, the easier it is to pedal and smallest is the hardest. the left handed shift lever makes larger differences in effort. Operating this lever moves the chain between the two or three chain rings on the front crank of your drive train. In the front, the larger the ring is the harder it is to pedal and smaller is easier. Front shifting is used less frequent than the rear. Those who ride in flatter areas don’t shift the front much at all.
Modern bicycles may have up to 27 gear combinations, but it is not recommended to use all of them. Imagine keeping them somewhat inline front to back as illustrated on the right. If the front gear is in low then keep the back in a lower gear. If the front in the middle then the middle gears for the back. Lastly if in the high gear in the front then high gear in the back. It's bad to cross the gears low to high, or high to low. Those gear ratio are going to be redundant, and more importantly you are creating side to side stress on your chain. This stress will lead to premature wear on the chain, resulting in slipping when more pressure is applied or even failure and breaking.
A good tip to remember is when the chain is closer to the bike frame, front and rear, you’re in your easier gears for climbing. As the chain shifts to the right away from the bike frame, the gears get harder for going faster on the flats.