How to Replace Frame Dropouts
By Madison Garcia

A bicycle dropout is a bike component that allows the rider to remove the rear wheel without derailing the chain.
It is part of the fork end of the bicycle, which is a slot that holds the axle of the wheel.
Dropouts were prevalent on bikes built before 1990 and are popular for converting a bike to single speed.
However, steel and aluminum bikes do not have replaceable dropouts,
so new trackends must be welded onto the dropouts to function safely. Always wear safety goggles while welding.


1 Place one threaded bar between the new dropout and another bar between the old dropouts.
Attach the two bars by tying them together with a piece of string.
The line formed by the string indicates where to install the trackends on the dropout.
Use a pen and mark this line on both dropouts.

2 Cut the tabs off the trackends. Insert the trackends on the new dropouts.
If the trackends do not fit perfectly, grind the edges of the dropouts with the angle grinder until they are flush.

3 Weld the trackends onto the dropouts. Make sure the welding stickout is about a quarter of an inch away from the surface of the metal.
Weld in short spurts to minimize any possible heat damage to the carbon bicycle.

4 Allow the bicycle to cool overnight after welding. Grind down any rough edges with a grinder.

5 Sand and paint the area around the new frame dropout to minimize any possible rusting.
Sand the frame with 100-grit sandpaper and wipe the area down with a damp rag.

6 Place the bike outside or place newspaper under the bike.
Hold the spray can approximately five inches away from the bike and spray an even coat over the sanded area.
Allow the bike to dry for an hour, and apply a second and third coat as needed.