Guided and Self-Guided
Mountain Biking and Walking Holidays
in Cyprus
 

 

Single Speed Build - Time to be a mechanic.

First step is to get the parts that you need:

  • A Single speed converter kit.
  • A chain tensioning device.
  • 5 or 6.5mm chainring bolts depending on crankset.
  • A chain half link.

And make sure that you have the right tools.

  • Cassette lockring tool
  • Chain whip
  • Set of Allen keys.
  • Chain tool (Unless you use quick links).

Yippee, the bits have arrived we've got the tools so let's build the bike.

Chain. Split and remove this from the bike. If it's worn bin it.

Gears. We don't need these anymore so get rid of shifters, gear cables and front and rear derailleur

Crankset. Lose the small and large chainrings. Keep the middle chainring. The existing chainring bolts will be too long to hold the single chainring snugly in place so use some shorter bolts or pad out the bolts with washers.

At the back. Using your chain-whip and lockring tool remove the rear gear cassette and replace it with a single speed converter kit. These kits contain a single sprocket and spacers which fit snugly onto your old freewheel hub. Use the spacer so as to get the best chainline possible.

Chainline. This is the line between the front chainring and the rear cog. On a single speed the chainring and rear sprocket should line up perfectly.

Getting the best chainline. Use the spacers supplied with the single speed converter kit to move the rear sprocket inwards or outwards on the rear freewheel until it is perfectly in line with the front chainring. This is a trial and error session. Take your time and get it right. Some kits have more spacers than others and more spacers equals greater range of adjustment.

Get a chain (old or new) back on. Put the wheel back on the bike. Wrap the chain around the front chain ring and rear sprocket. Get the chain as short as you can but not so tight that the drivechain binds. This bit is frustrating and a mere couple of millimetres is the difference between too loose and too tight. It is possible to buy "chain half links". These are shorter than a standard link but they do exactly the same job. Get the chain length exactly right and you may not need a chain-tensioner.

Chainwrap. The chain should wrap around the rear sprocket as close to 180degrees as is possible. Think of it as a U-turn. Get the chain length as short a possible before fitting the tensioning device.

Chain tension. The most important bit. If you have a frame with horizontal wheel dropouts you are lucky. Simply move the wheel backwards until you get good tension and bolt it in place. If you are converting an old hardtail chances are that you have vertical dropouts. If so, you will probably need a chain-tensioning device to take up any slack. If the chain is too loose, when you put the power down it will jump resulting in potential considerable pain. A chain tension device will take some slack out of the system but only once you have got the chain as short as possible.

The most popular devices these days mount to the now unused gear hanger while others fix onto the chainstay. They can be spring loaded or fixed. They push up or down on the chain taking up any slack.

That's it job done, time to ride. Everything is now in place so go for a test ride. You may have to fettle a little to get things perfectly smooth but if you have taken your time you will have a smile on your face and a burning sensation in your legs and lungs.

Recap the important things.

  • Chainline. Front chainring and rear sprocket should line up with each other perfectly. Use the spacers provided with the converter kit to move the sprocket in and/or out on the freehub until the correct chainline is achieved.
  • Chain length. Get the chain length as short as possible, don't just rely on the tensioning device.
  • Chainwrap. A sprocket only works well if the chain wraps around it covering at least 120degrees. Aim to wrap as close to 180degree as is possible.
  • Chain tension. This is critical; too loose and the chain will slip/jump, too tight and the drivetrain will bind.

Al - 26th February 2009.