Idiot’s guide to gear shifting – Part 1 (Technology)

It may sound beneath you, but given the number of people James Thornhill-Fisher saw struggling over the basics of gear shifting while coaching during the holidays he thought he’d better address the issue. So it’s back to the basics to help you extend the life of your components and get the most out of your riding.

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Introduction to Gears and Terminology

Ever since bicycles came with more than one sprocket on the front and back, they were usually referred to as the number of gear combinations that were offered. For example, a road bike with two chainrings up front and a five-speed freewheel on the back was a “10 speed,” since the five rear sprockets could be matched with either of the two front chainrings. (2×5=10, it’s just simple mathematics.) But once you learn more about gearing, you’ll see that that is actually a confusing way to describe things. So to start things off, let’s get the terminology straightened out.


The front sprockets that are attached to the crankarm are called chainrings. If you have two chainrings (a big ring and a little ring) that setup is called a “double.” If you have three chainrings (big, middle and little) you have a “triple” chainring setup.


The gear cluster on the rear wheel is either a freewheel or a cassette. If your bike has five gears on the back, it probably has a freewheel. If your bike has eight to ten gears on the back, it has a cassette. Each ring on the cassette is referred to as a cog. (The difference between a freewheel and a cassette makes no difference in this guide, so don’t worry about that.)

For this guide, our example bicycle will be a mountain bike with three chainrings and a 9-speed cassette. Some people would call this a “27 speed”, but most avid cyclists and bike mechanics refer to this simply as a “9 speed”.

 Discover how the Shifters and Derailleurs Work

Having gears won’t do you a bit of good without understanding how the shifting works, so here’s a look at that.

Shifting starts at the shift levers, which are usually located on the handlebar beside the grips. When you move one of the shift levers, a cable pulls or releases one of the derailleurs which moves the chain from one gear to another. In typical setups, the left shifter is matched to the front derailleur (so it shifts between the chainrings). The right shifter is matched to the rear derailleur (which shifts between the cogs on the cassette).

Let’s talk about the shift levers (“shifters”) first… Each shifter will (in the case of the lower specification shifters) have numbers on it to indicate which gear you are in (this is the gear indicator). In this example, our left shifter shows numbers 1-3, while our right shifter shows 1-9. The lower the number, the easier the gear is. So if both the gear indicators show “1″ then you are in the easiest gear the bike offers. If the left shifter is at 3 and the right is at 9, then you are in the hardest gear on the bike.

On the left shifter, you will see numbers to indicate which gear you are in – 1, 2, or 3. The number 1 corresponds to the little ring, 2 is the middle ring and 3 is the big ring. For the front chainrings, bigger chainrings equal a harder gear.

On the right shifter, the numbers 1-9 are all there. The number 1 corresponds to the biggest cog, while number 9 corresponds to the smallest cog. When it comes to the cassette, bigger cogs equal an easier gear. While I’m using a 9 cog cassette as an example, most new bikes will come stocked with a 10 cog cassette and some top end models feature 11 cog cassettes.

This is the easy part though, because once you shift the levers, the shifter cable will relay your instructions to the derailleur. What happens when you shift is the derailleur cage (which the chain runs through) will move to either side. Let’s say you shifted the front shifter to an easier gear. The front derailleur will move to the left, thereby “derailing” the chain onto the smaller chainring as long as your derailleurs are adjusted properly…

Types of Shifters

Before moving on to shifting and gear selection, let’s take a quick look at the various types of shifters out there.

Grip Shift

Grip shifters – these operate without levers and you shift gears by twisting a section of the grip either forwards or backwards.

Trigger Shift

Trigger shifter – these operate with two levers, one to shift up and one to shift down.

Choosing the Right Gearing for your Ride

If you’re less fit, new to mountain biking or riding a wide range of terrains (including long distances on the road) the 3 x 9 or 3 x 10 setup commonly seen on bikes in the lower price points will be perfect for you.

If you’re keen on racing, especially stage racing then I’d recommend 2 x 10 as it’s a lighter set up, less prone to chain suck and all round simpler system, so there’s less to go wrong.

If you’re an avid racer, you already know 1 x 11 is the way to go. And if you’re old school, or looking to get super strong, it’s single speed all the way.

Next month

I’ll be covering the fundamentals of gear selection.

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