| Mountain bike gears are continually becoming | | | | pedaling at a consistent pace, no matter what |
| more and more complicated and intricate. | | | | terrain you are on or what your speed is. |
| Today’s bikes can come with up to 27 | | | | |
| gear ratios. It is common for a mountain bike | | | | A typical mountain bike that has 27 gears |
| today to use nine gears in the back and three | | | | will have six gears so incrementally close to |
| sprockets of different sizes in the front for | | | | the other that you will not be able to |
| gear ration production. | | | | determine that there is any difference |
| | | | between the gears when you change them. |
| Why so many gears? The most common reason is | | | | |
| that a large number of gears allow a rider to | | | | Most mountain bike riders decide to choose a |
| pedal at the same pace no matter what terrain | | | | gear system with a front socket that is |
| that he/she is on. This can be understood | | | | suitable for the slope or terrain that they |
| better if you think about a bike that just | | | | usually ride on and they stay with this |
| has one gear. Every time you turn the pedals | | | | choice, even though it may be more difficult |
| one full turn, then the rear wheel also turns | | | | under a heavy load to shift the gears. This |
| one full turn, too (1:1 gear ratio). | | | | is purely a personal decision, but it is |
| | | | simpler to shift between gears when the rear |
| For example, your back wheel is measured at | | | | socket, rather than the front one. |
| 26 inches. If you pedal one full turn, then | | | | |
| this would mean that your wheel moved 81.6 | | | | When you are pedaling uphill, then you will |
| inches. If you are riding at 50 RPM, then you | | | | find that it is much better to choose a |
| will be able to go 340 feet per minute. This | | | | sprocket that is smaller on the front and |
| means that you were going 3.8MPH, which is | | | | then shift gears with the nine gears that are |
| equivalent to walking speed. This speed is | | | | available on the rear. If you are more speeds |
| great for going up a hill that is steep, but | | | | on the rear sprocket, then you will find that |
| it is not a good speed for flat ground or | | | | it is much more efficient to ride. |
| racing downhill. | | | | |
| | | | Mountain biking needs gears so that you can |
| If you want your bike to go quicker, then you | | | | keep an overall speed going. If you |
| will need a different ratio. If you want to | | | | didn’t have gears, then you would find |
| reach a speed of 25 MPH downhill using a | | | | it difficult to build up any speed and you |
| 50-RPM cadence, then you will need to have a | | | | would find it nearly impossible to pound your |
| 5.6:1 gear ration. If you have lots of gears | | | | pedals for extra control. Gears help to move |
| on your bike, then you will be able to get | | | | the pedals and enable you to gain that speed. |
| that ratio so that you can continue your | | | | |