Many road cyclists choose to use a fixed gear road bike. Not only are they simple and fun to ride, they can be used to improve cadence and strength. Converting an existing road bike is a good alternative to buying a new fixed gear road bike. Knowledge of bicycle part terminology, bicycle measurement standards, and intermediate maintenance skills are required for this procedure.
Things You’ll Need:
- Road bike with horizontal dropouts
- Pencil and paper
- Repair stand
- Wrenches, metric set up to 15mm
- Hex wrenches: metric up to 8mm
- Chain tool
- Caliper or ruler
- Rear wheel with a fixed gear hub
- 3/32 inch rear cog
- Cog lockring
- Chain whip
- Lock ring wrench
- Bottom bracket removal tool
- Crank puller
- Bottom bracket installation tool
- Crank arms, chainring and bottom bracket
- Torque wrench
Choose a bicycle with horizontal rear dropouts or track ends. Ride the bicycle and take note of the desired gear combination and crank length.
Mount the bicycle into a repair stand. Remove the rear wheel, front derailleur, rear derailleur, shifters (if separate from the brake levers) and chain. Set the chain aside. Remove the crank arms and bottom bracket. Measure and record the rear spacing of the rear dropouts.
Select a rear wheel with a fixed hub that has an over locknut dimension matching the rear drop out spacing measurement. Clean and grease the threads on the hub. Install a 3/32-inch fixed cog to the hub with the correct amount of teeth to obtain the desired gear ratio with the selected front chainring. Tighten securely with a chain whip. Install the lockring and secure using a lockring wrench. Wipe off excess grease.
Measure and record the chainline of the rear wheel. Select a crank arm and bottom bracket combination that will give you a front chainline that is within 1mm of the rear chainline. The closer the better. Measure the bolt circle diameter (BCD) of the crank arms and select a chain ring with the correct BCD and teeth number to obtain the desired gear ratio.
Install the bottom bracket, chainring, crank arms, and pedals to the required torque. Refer to component installation instructions for procedures and required torque values. Clean and grease all threads.
Install rear wheel at the center of the rear dropouts and tighten the rear axle nuts so they are snug and the wheel will not move. Size the chain by wrapping it around the chainring and cog. Pull it tight and determine the best location to break the chain. Refer to the instructions that came with the chain for installation procedures.
Loosen the rear axle nuts and slide the wheel forward in the drop outs, place the chain on the front chainring and cog, pull the wheel back in the drop outs, center it, and tighten the axle nuts to a torque of 260 to 390 in-lbs. It is important to have proper chain tension. If the chain will not move up and down, it is too tight. If the chain moves more than an inch up and down, it is too loose.
Rotate the pedals and inspect the chain line and chain tension for accuracy. Remove the bike from the repair stand and put your weight on a forward pushing pedal while holding the bike stationary in order to tighten and set the cog. Tighten the cog lockring to the required torque. If there is no required torque for the lockring indicated, get it as tight as possible with a six inch wrench.
Tips & Warnings
- If the bike does not have horizontal drop outs, an eccentric hub can be used to attain proper chain tension. A specific gear combination dependent upon the chainstay length may also be determined for bicycles with vertical dropouts.
- Refer to installation manuals for required torque measurements.
- If your frame is steel, the rear spacing may be adjusted by cold-setting the frame.
- If you wish to use your existing crank arms, the chainring must be positioned to attain the desired chainline. This can be done using chainring bolt spacers or a bottom bracket with a different length spindle.
- Different chain brands have different installation methods. Refer to the installation manual provided with the product.
- Keep your fingers and any loose clothing away from the chain while spinning the drivetrain. A finger caught in between the chain and rear cog of a fixed gear bicycle can be severed.