Turn an Old Road Bike Into a Singlespeed
Turn a vintage geared road bike into a single speed.
Steps
- Check the rear dropout shape. Does the bike have horizontal dropouts in the back? This is necessary to be able to adjust chain slack in the final step. Alternately, you can buy some kind of doohickey to do it, but that ruins the clean look so vitally important to most conversions. What this means is, can you adjust where the back wheel goes, in a front-back direction. Some bikes have vertical dropouts, some have slanted ones. There has to be some way to adjust wheel position and chain tension. In a normal bike, the rear derailleur does this job. You could leave it on, but your little fixed gear friends will snort.
- Determine your gear ratio. This is the tooth ratio of your front chain ring to your rear cog. The best way to do this is by riding around for a few days trying various combinations between your front and rear. A typical ratio is a 48 tooth chain ring on your crank set, and a 16 tooth freewheel on your rear hub. Alternatively a 52 tooth chain ring and 17 tooth freewheel works for many as well. Keep in mind that the lower your ratio (less teeth in the chain ring or more teeth in the freewheel), the better you'll climb hills, but the slower you'll be on the straightaways and vice versa.
- Take off unnecessary parts such as derailleurs, shifter cables, cable housings, and shifters. For a freewheel equipped single speed bike its highly recommended that you leave on both front and rear brakes. Unlike a fixed gear bicycle, a freewheel equipped single speed relies 100% on the brakes for stopping. Thus for safety you need both. With a fixed-gear bicycle, pushing back on the pedals can take the place of the rear brake and used for light braking, though at least a front brake should be fitted and used as the primary brake.
- Most older road bikes have a double chain ring crank set. In order to attain that "clean" look you should remove both and either install a new chain ring or one of the older ones (depending upon your preferred ratio.) Usually it helps to install the single chain ring on the INSIDE of the crank spider so that your "chain line" is straight. Pay special attention to clearance with the lower drive side chain stay if you're using a large chain ring (48 or larger) on the inside. In most cases you will need to use chain ring bolts specifically for single ring applications.
- Using a freewheel remover specific to your brand of freewheel, remove your old freewheel and replace with a new single speed freewheel. Alternatively you can buy and install a new "flip-flop" wheel which would allow you both to ride single speed and fixed gear. If you have a cassette on a free hub body, you can either use the complete cassette, or for a cleaner look install a single speed cog and use spacers to make sure the chain is straight (adjust chain line).
- Your rear wheel may require what is called "re-dishing" in order to insure that your wheel runs straight in the rear triangle. Sometimes you can get away without doing this, but if your wheel runs leaning to one side or the other, consider re-dishing.
- Using a chain tool, shorten your chain for the new ratio.
- When installing your rear wheel ensure that the chain tension is not too tight and not too loose. Holding the bike up spin the cranks to make sure everything is spinning smoothly. Excessive noise, or a dropped chain means that something is wrong, most likely in the chain line.
Warnings
- Anytime you make adjustment or changes to your bicycle take it easy for the first few rides and double and triple check your changes.
- Always use front and rear brakes on a single speed (non-fixed gear) bicycle. If one brake fails you'll have the other to stop you.
- Always wear a helmet.
Things You'll Need
- Numerous specific bicycle tools including a freewheel or cassette remover, allen wrenches, etc.
- Single speed freewheel or a single speed cog and spacers.
- Single ring chain tug bolts
- Possibly a new "flip-flop" or "single speed" specific wheel set.
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