Bike Anatomy

So do you know your derailleur from your down tube, your rear cogs from your crank arm? If the answer is no to either or both, then what are you doing on a bike?

Too many riders adopt the same attitude as car drivers: “Oh, who knows what goes on under the bonnet. All I know is how to turn the ignition key and hold the steering wheel. Mechanics is best left to the men or women in the oily boiler suits.”

Well that’s just fine and dandy, until your car or bike malfunctions in the middle of nowhere. No phone? Well, mobiles have alleviated much of the problem of calling for help in remote areas.

But while a garage can see the advantage in negotiating a dirt track to come to the aid of a broken down Roller or Mercedes, a bike rider in distress hardly represents a cash cow.

So you are going to have to be prepared to help yourself. And the first step is learning how the bike is constructed and what makes it move.

Connected by the Frame

Start off with the basics: saddle, wheels and handlebars – everyone’s heard of them. All three extremities of the construction are connected by the frame, which is itself made up of a number of parts.

The head tube is situated at the front of the bike and is the extension where the maker’s badge is usually positioned. It acts as a sleeve through which the fork runs that connects the handlebar set to the front wheel.

Branching out from the head tube is the top tube, sometimes referred to as the cross bar, and, lower down, the down tube which connects with the pedals. Extending vertically from the pedals is the seat tube which by means of the seat collar, connects with the seat post that is topped off with the saddle.

Extending backwards from the seat tube is the seat stay tube. This forms a junction at the centre of the rear wheel with the chain stay tube.

From Cog to Cog

Now let’s deal with how the wheels turn. The pedal connects to the chain rings, or front gears, by means of the crank arm. Moving the chain from one ring to another is the job of the front derailleur.

On the rear wheel you will find the cassette, or rear cogs, and the rear derailleur, which in common with its twin at the front, moves the chain from cog to cog.

What is commonly referred to as the wheel is, in fact, made up of a number of elements: namely, the rim, spokes, hub, inner tube and tyre.

Finally let’s return to the steering column where you will find the handlebars, either drops as in a road racing bike, or flats, together with the brake levers and the shift, or gear, levers.

All of these connect to the head tube via the stem and the headset.

Initially, all this can sound like double Dutch, but take the time to sit back and analyse the construction of the bike and its component parts, and everything quite literally falls into place.

So when a problem arises, or something either doesn’t feel or sound right, you will be in a position to act quickly and decisively.