Trick ferrets only need one gear, as speed and flow are their natural allies. For the rest of us however, there are a lot of options when it comes to gearing and how many cogs to run. Gear range can dramatically affect your bikes usability and is often heavily influenced by where and how you ride.
Roughly speaking, the wider the variety of gradients you ride, the more gears or wider spread of gear range you want. Take DH racers for example, they only go downhill so they only need the very tallest ratios and typically run between 10 and seven rear cogs. Cross country racers on the other hand need to go up steep things, as well as down, so they need a wider spread of gears. Should I run a single ring at the front?
That is a very popular option now and for good reason. The smallest ring is 1, the middle ring is 2, and the biggest ring is 3.
The right shifter changes the ring on the rear wheel. This is opposite of the front set: On the rear wheel the biggest ring is 1, and the smallest ring is 6. You can downshift with either shifter, moving it from a higher number to a smaller number. You get a bigger change when you shift with the left-hand shifter than when you shift with the right-hand shifter. The solution? Downshift to first gear. How does that solve the problem? First gear moves you a shorter distance for each spin of the pedals, which makes it easier to pedal.
Click HERE to check it out. If you need a small change, use the right one. Try to keep the chain in a sort-of straight line between the front and rear sets, rather than going at an extreme angle from left to right.
For example, in the very lowest gear, the chain will be all the way on the left on both sets. The lower gear range you get from a compact chainset is why they have become so popular in the last decade. With its WiFli transmissions, SRAM has taken this to its logical conclusion, combining a compact chainset with a very wide range cassette.
The advantage of a triple is that, done right, it can provide a very wide gear range with small gaps between ratios. The disadvantage is that even with the best indexed gears it can be a struggle to have the shift to the middle ring and down to the inner ring work perfectly. However, use the right components and you can go much lower. It's not usual for gear freaks to custom-blend set ups that go lower still.
My tandem has an 18in low gear, provided by a tooth chainring and a tooth sprocket. Single chainrings have become popular among mountain bikers for their simplicity. Racers like not having to think about front shifting, while for recreational riders who have adopted height-adjustable seatposts it declutters the handlebar. Chainrings for double and triple cranksets are designed to make it easy for the chain to come off, so it can move to the next ring.
That makes them unsuitable for use as a single rings. To get a wide spread of gears, single ring systems use 10 or 11 sprockets ranging in size from tiny to huge, as you can see in the above pic. The price for simplicity is that compared to other ways of getting a wide gear range there are some big gaps in there.
The middle sprockets do give you a useful selection of ratios for general riding though. If you like road. As a subscriber you can read road. The revenue from adverts helps to fund our site. Your subscription will help us to do more. John has been writing about bikes and cycling for over 30 years since discovering that people were mug enough to pay him for it rather than expecting him to do an honest day's work. He was heavily involved in the mountain bike boom of the late s as a racer, team manager and race promoter, and that led to writing for Mountain Biking UK magazine shortly after its inception.
He got the gig by phoning up the editor and telling him the magazine was rubbish and he could do better. Along with road. Likewise a double chainring paired with an speed cassette is a speed set-up, and so on. Why have gears at all? Well, in a nutshell, gears are there to enable us to maintain a comfortable pedalling speed or cadence regardless of the gradient or terrain — something that no one single gear is capable of.
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.
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