Author Topic: Singlespeeding

sam

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Singlespeeding
« on: December 30, 2007 »
There is nothing wrong with having more than one gear per bicycle. Choice is a good thing, poetic propaganda[1] from the singlespeed/fixed wheel lobby to the contrary. That said, here are benefits of staying single:

  • Fewer parts means it's easier to maintain. If you're normally shy about bike repairs and adjustments, having a simpler drivetrain might make the prospect less daunting.
  • It's theoretically cheaper. In practice this isn't always the case, as people often compensate by buying expensive components.
  • Riding a fixie[2] (no coasting allowed) is said to smooth out your cadence, if that's high on your list of priorities.

The main disadvantage is when you're in the wrong gear and can't do anything about it other than change bikes.[3] Optimists will suggest that you're never in the wrong gear; pessimists will counter that you're never in the right one.

Singlespeed branches off into freewheel or fixed. The yawning difference is the rear hub. With fixed, a simple cog is screwed onto the side of a hub designed for it. With freewheel, either a special freewheel cog with bearings is used on a singlespeed-specific hub, or an unthreaded one is slid onto a freehub (on a previously multigeared bike) along with spacers where the other cogs were; there are also a few freewheel-specific singlespeed hubs.[4]

You can of course just leave the chain on the most appropriate cog on your multigeared bike. This has the advantage of being an easy decision to walk back.

Conversion on what we'll call a regular bike isn't too difficult. If the fork ends are horizontal or at a suitable angle this will be easy: with no rear derailleur to take up chain slack,[5] the rear wheel is merely pushed back until it's reasonably taut. If it's a vertical dropout, as most are these days, you'll have to either add a chain tensioner (though this won't work with fixed), use an eccentric bottom bracket or hub, or conjure a 'magic gear', which is a combination of chainring and cog and chain length which is both comfortable for you to pedal and tight enough to keep the chain from skipping or falling off.

   
Horizontal then vertical, depending on the angle of your computer screen


Converted rear hub with a magic gear

You'll need to decide which combination of chainwheel and rear cog works best for your style of riding. No recommendations will be made here, other than that the author started with a 42x16 and finds that suitable for most rides, even moderately hilly ones.


See also

Notes
1 - References to Zen are unavoidable. The only enlightening thing about it is probably the weight.
2- The term 'fixie' is now about as popular with aficionados as 'sci-fi' is with sf lovers. And fixed wheel / fixed gear refer to the same thing. Fixies.
3 - Or flip the wheel to a different cog at the ready. Or change cogs. In other words, it just takes longer to change gears.
4 - One example.
5 - Speaking of which, be prepared for "chain's a bit slack" comments when posting pictures of your bike on forums if you aren't vigilant about tautness.


External links