How do racing bike gears work

That gives you a huge range of gears to choose from. Hub gears are a popular option for commuters and those who want a robust and relatively maintenance-free drivetrain. With service intervals ranging between 3, to 5,km, internal hub gears are great for the less maintenance-inclined. However, the main drawback is weight. Part of the problem of a hub gear is that it adds weight at one end of the bike, which can lead to unbalanced handling.

Instead, a gearbox is integrated directly into the frame, with the weight positioned centrally on the bike. The cranks drive the gears directly and the output is converted in the gearbox and then transmitted to the back wheel via a chain.

One of the most exciting development in recent times is the Pinion gearbox. However, in general, gearboxes remain a niche in the bike world. Both gearboxes and hub gears can also be used with belt drives. This requires even less maintenance than a chain because there are no links to lube, meaning they are also much cleaner than an oily chain. However, only certain frames are compatible with a belt drive.

Because the belt is a continuous loop, the frame requires removable dropouts or a chainstay splitter that lets you thread the belt into the rear triangle. The majority of gears on bikes today are actuated by metal cables — bowden cables to use their proper name.

However electronic drivetrains have been on the market for some time now, and are only likely to become more widespread as time goes on.

Instead of cables, the gear is shifted by an electronically controlled motor. The primary benefit is consistency. While cables can develop slop and stretch over time, an electronic drivetrain will maintain accurate shifting in all conditions. Of course, the drawbacks are that batteries need to be charged though not on a particularly regular basis and, currently, the expense. Even Rohloff now offers electronic shifting for its speed hub gear. Singlespeed bikes use a single cog that can freewheel and allows the rear wheel to rotate without the pedals moving.

The main benefit is simplicity, with low maintenance requirements and low cost. Shifters for the front and for the rear will be separate, located on the left and right side of your bars respectively.

There are a few different shifter designs available. Nowadays, the trigger shifter is the most wide-spread design. It has two levers under the bars, which can be actuated with your thumbs or fingers: one to shift up and one to shift down. Depending on the design, you may be able to change multiple gears at once or not. Cross chaining occurs when you use the big chain ring on the front and your largest cog on the cassette the cog with the most teeth or when you use the small chain ring on the front and the smallest cog on the cassette fewest teeth.

These two gearing combinations should be avoided to prevent damage to your bike and drivetrain. Waiting too long to shift slows you down and kills your momentum. This makes for an easier shift without grinding your gears and allows you to start the climb without losing too much speed.

Dropped chains are commonly caused when applying too much torque through the pedals while attempting a shift. Before you decide to shift from the small to the big chain ring or vice versa , speed up a little and then lighten up on your pedal stroke. The decrease in tension on the chain, puts less pressure on the derailleur and makes for an easier shift while decreasing your chances for throwing your chain. Marc is a freelance writer based in Scottsdale, Arizona.

He is the former cycling editor for Active. Turn on MapMyRun desktop notifications and stay up to date on the latest running advice. Share it:. Tags bike handling basics cycling technique tips training tips.

About the Author. Vice versa, combining the smallest front chainring size with the largest rear sprocket size results in the lowest available gear, which will help you keep the pedals spinning when the road points steeply up. A bike with 30 or more gears is not an indication of a machine designed to break the land speed record any more than a bike with only a single gear, assuming similar ratios.

Just like a car, bicycles benefit from a low gear to accelerate from a standstill, or to climb a steep hill, and at the other end of the scale a high gear helps you to achieve high speeds without over-revving. Continuing with the car example, using too low a gear at high speed would result in high fuel consumption.

The same is true of your body pedalling a bike. So, quite simply, more gears means more scope to find your preferred pedalling speed. To put this into perspective, in the days of five or six-speed cassettes, a range of teeth could only be achieved by having sizeable gaps between sprocket sizes. Modern speed cassettes with the same spread, , would have only single tooth increments for the majority of the shifting. The result is smoother, more precise shifting, as the mechanical difficulties the chain has to overcome to climb onto the bigger sprocket or drop down onto a smaller one are much reduced with smaller increments, but most importantly, the possibility is there to greatly improve pedalling efficiency.

Cyclists are much more able to fine-tune their pedalling speed to suit the gradient or terrain, often resulting in a lower energy cost. You don't have to ride a bike with gears - some people choose to ride singlespeed bikes. These still have a gear - which is determined by the size of the front chainring and rear cog. Singlespeed bikes are popular among commuters living in flat areas, because they require little maintenance. They're also used by some racers hill climbers for example who want to drop weight and cut down on any extra complication coming from the shifting process - in this case, choosing the correct gear ratio is crucial.

Finally, track bikes only ever have one gear - though again riders will change their set up to suit certain events. In other words, some gear combinations will result in the same ratio as others using a different sprocket and chainring. For example, 53x19 is the same gear as 39x See the diagram below for an illustration of this. The result is a larger cassette rear gears that has more cogs and often more teeth on the largest cog in the cassette.

Because, generally, having less chain rings makes the bike more efficient, lighter weight and easier to operate and adjust. This is the reason you will often see one-by drivetrains on high-end mountain bikes and two-by drivetrains on the high-end road bikes. So, now that you have a basic understanding of what those gears are called, how do you shift?

Depending on the type of bike you have your shifters may look a little different. On road bikes or any bike with drop handlebars , your shifters are the same levers you use to apply your brakes. To operate the shifters you push the lever sideways until you hear a click.

For most mountain and hybrid style bikes with flat bars, you shift the gears by using set paddles that you operate with your thumb. For these systems, you change gears by rotating the dial forward and back.

Your shifters are connected to a cable encased in a protective housing. As you click through the gears, the cable is tightening and loosening, applying more or less force on the derailleur that moves your chain up and down on the cassette or chain rings.

Below we will explain what each lever does:. These levers cause big jumps in gears for sudden changes in terrain.

These levers are for small adjustments to your gearing to use during slight changes in terrain. This means there is a smaller lever tucked behind the larger brake lever and you can move it in only one direction.