Use a Brake
By MrFixie
Advice on Brakes
Slowing down on a fixie can be accomplished several ways. Because the gear is fixed, you use your legs to slow down by resisting the inertial direction of the cranks. If you can recall back to your early days on a tricycle, it is a similar concept. Skid stopping is another method of slowing down, but shouldn’t be relied upon when an emergency arises and you need to come to a sudden stop.
Depending on the size of your gear, you may not be able to slow down fast enough with your legs. It is recommended that you have a front brake for this reason. Suppose you are riding down the street and a car door suddenly opens five feet from you as you move 15mph. You don’t have to do the math to know that you either swerve or you faceplant. Swerving is not always an option either if there is a car coming. Hopefully the older road bike you have purchased has front and rear calipers. You can remove the rear if you like (keep it if you intend to ride single speed) and just run the front brake. You can use the existing lever or purchase an aftermarket lever to use with your old caliper.
If you’d like to upgrade your brake, consider these items:
BMX lever
Inline top bar levers: Tektro RX 2.1 Oversized In-Line Lever
MTB lever

