You can change gears to keep pedaling at the same cadence in changing environment. It would help if you switched to lower gear when going uphill, and higher gear going down.
The joy of the mountain bike is that they come with so many gears that, if you shift into the lowest one, you can ride up a mountain with no problem. It may take you all day, but you can do it.
Mountain bike gears are continually becoming more and more complicated and intricate. Today’s bikes can come with up to 27 gear ratios. It is common for a mountain bike today to use nine gears in the back and three sprockets of different sizes in the front for gear ration production.
Why so many gears?
The most common reason is that a large number of gears allow a rider to pedal at the same pace no matter what terrain that he/she is on. This can be understood better if you think about a bike that just has one gear. Every time you turn the pedals one full turn, then the rear wheel also turns one full turn, too (1:1 gear ratio).
For example, your back wheel is measured at 26 inches. If you pedal one full turn, then this would mean that your wheel moved 81.6 inches. If you are riding at 50 RPM, then you will be able to go 340 feet per minute. This means that you were going 3.8MPH, which is equivalent to walking speed. This speed is great for going up a hill that is steep, but it is not a good speed for flat ground or racing downhill.
If you want your bike to go quicker, then you will need a different ratio. If you want to reach a speed of 25 MPH downhill using a 50-RPM cadence, then you will need to have a 5.6:1 gear ration. If you have lots of gears on your bike, then you will be able to get that ratio so that you can continue your pedaling at a consistent pace, no matter what terrain you are on or what your speed is.
A typical mountain bike that has 27 gears will have six gears so incrementally close to the other that you will not be able to determine that there is any difference between the gears when you change them.
Most mountain bike riders decide to choose a gear system with a front socket that is suitable for the slope or terrain that they usually ride on and they stay with this choice, even though it may be more difficult under a heavy load to shift the gears. This is purely a personal decision, but it is simpler to shift between gears when the rear socket, rather than the front one.
When you are pedaling uphill, then you will find that it is much better to choose a sprocket that is smaller on the front and then shift gears with the nine gears that are available on the rear. If you are more speeds on the rear sprocket, then you will find that it is much more efficient to ride.
Mountain biking needs gears so that you can keep an overall speed going. If you didn’t have gears, then you would find it difficult to build up any speed, and you would find it nearly impossible to pound your pedals for extra control. Gears help to move the pedals and enable you to gain that speed.
It’s been a long time since the 10-speed bike was the plus ultra of biking sophistication when it came to gears. These days, especially in mountain bikes, you can get anything up to 27 speeds.
What are all these gears in aid of?
Quite simply, they allow you to pedal at the same cadence – regardless of whether you’re going uphill, downhill, or cross country.
However, the main reason why mountain bikes have so many gears is to assist you in climbing up those mountains!
The main thing to remember when shifting is that you must always shift while pedaling, otherwise you’ll strip the gears.
The gears are divided into two parts. There are three chain rings in the front, which are controlled by the left-hand gear shifter. That’s why there are three numbers to choose from on that gear shifter – to choose which of three front rings your chain will rest on. The “derailleur” attached to the gear shifter moves the chain from one ring to another.
When the chain is on the smallest of these three chainrings (1), pedaling will be very easy. This is called the granny gear. The second chainring is for level, off-road riding (2), and the third, or largest chain ring is good for riding on pavement.
So if you want to use just those three gears, you can certainly do so. But, using the right-hand shifter, you can take advantage of the increments of gears available to you.
The back chainring is a cog set featuring seven, eight or nine cogs, depending on how many “speeds” you have (21, 24 or 27). Each cog is of a different size, and again, the smaller size cogs will enable you to pedal very, very easily – but not go very fast, while the larger size cogs will allow you to go further with each downward stroke of the pedal.
The best thing to do is to practice, practice, practice. Take your bike to a parking lot or somewhere where you don’t have to worry about people and shift from one gear to another, getting used to each one and how easy or difficult it is to pedal while in that gear.
People new to biking might be rather wary of shifting gears. Shifting always was a bit problematic during the “old days” – when one only had a pair of center-mounted levels to work with, but now gear shifters – the twist type – are so easy to use that there is no reason to be afraid of shifting. Again, as long as you’re pedaling while you shift, you won’t hurt the gears.
How Mountain Bike Gears Work
The gears in mountain bikes keep getting more and more intricate. The bikes of today have as many as 27 gear ratios. A mountain bike will use a combination of three different sized sprockets in front and nine in the back to produce gear ratios.
The idea behind all these gears is to allow the rider to crank the pedals at a constant pace no matter what kind of slope the bike is on. You can understand this better by picturing a bike with just a single gear. Each time you rotate the pedal one turn, the rear wheel would rotate one turn as well (1:1 gear ratio).
If the rear wheel is 26 inches in diameter, then with 1:1 gearing, one full twist on the pedals would result in the wheel covering 81.6 inches of ground. If you are pedaling at a speed of 50 RPM,
this means that the bike can cover over 340 feet of ground per minute. This is only 3.8 MPH, which is the equivalence of walking speed. This is ideal for climbing a steep hill, although bad for ground or going downhill.
To go faster, you’ll need a different ratio. To ride downhill at 25 MPH with a 50 RPM cadence at the
pedals, you’ll need a 5.6:1 gear ratio. A bike with a lot of gears will give you a large number
of increments between a 1:1 gear ratio and a 6.5:1 gear ratio so that you can always pedal at 50 RPM, no matter how fast you are going.
On a normal 27-speed mountain bike, six of the gear ratios are so close to each other that you can’t notice any difference between them.
With actual use, bike riders tend to choose a front sprocket suitable for the slope they are riding on and stick with it, although the front sprocket can be difficult to shift under heavy load. It’s much easier to shit between the gears on the rear.
If you are cranking up a hill, it’s best to choose the smallest sprocket on the front then shift between the nine gears available on the rear. The more speeds you have on the back sprocket, the
bigger advantage you’ll have.
All in all, gears are very important to mountain bikes as they dictate your overall speed. Without gears you wouldn’t be able to build speed nor would you be able to pound pedals. The gears will move the pedals and help you build up speed.
There are all types of gears available in mountain bikes, all of which will help you build up a lot of momentum if you use them the right way.