Anatomy of a bicycle, #1

Good evening.

One of the things I've always found most confusing when learning about bikes are the terms used for the various different bits and pieces. Even when I've read fairly detailed descriptions or watched tutorials that go into some depth, there's usually some fundamental unexplained term that throws me.

And I figure that if I've been thrown, then maybe so have you. Hence this series of articles, starting with something fairly simple but very fundamental indeed - the wheel.

Picture courtesy of Herr Kriss

The wheel is made up of the following parts, starting with (hopefully) the most obvious first:

• Tyre: That hard black rubbery thing that goes all the way around the outside.
• Rim: The round metal bit that the tyre is tucked into.
• Inner tube: The inflatable bit of the tyre, which sits between the tyre and the rim. The only bit of it you can see is the valve, more on which later.
• Hub: The bit in the middle, which attaches to the rest of the bike, and hopefully stays there.
• Spokes: The long metal rods which attach the rim and the hub.
• Rim tape: This sits between the rim and the inner tube, to protect the tube from any spiky or sharp bits on the rim.

One of the things I'm planning not to do in my project to build a bike is to build the wheels up from all the individual bits - I think they're just a bit too important for an amateur to have a go at. In all likelihood, you'll generally always buy or replace a wheel in its entirety, which will reduce your relationship with the wheel to the following:

• Inner tube valves: There are two different types of valves in common use: Presta and Schrader. Presta valves are longer, thinner and pointier (the valve in the picture above is a Presta); Schrader valves are more squat and wider. The only reason I mention this is that one time I bought an inner tube with a Schrader valve, and tried to use it as a replacement for a Presta one. It should have been obvious to me at the time, but the Schrader wouldn't go through the narrower hole in the rim. (Thankfully the other wheel of this particular bike did have a hole big enough for a Schrader valve, so the inner tube wasn't so much a waste of money as it was a prudent investment.)
• Broken spokes: This is pretty terminal. If one spoke breaks, it puts more stress on the others and you're likely to end up with the wheel collapsing. If you break a spoke, get off and push it home. Even if it is tipping it down and you're late for tea.
• Loose hub: The whole wheel should be held in place so that it doesn't "jiggle" to either side of the centre when you're cycling. I have on occasion had it happen that the hub's come a bit loose - you can feel and hear it, especially when you go round corners - the bike doesn't feel quite "with" you any more. You may need a new hub, or it may be possible to get your existing one tightened up, it all depends on how severe the problem is.

That's all for tonight!