In this article I’m going to explain how to repair worn rear dropouts.
I noticed a significant amount of play in the rear wheel of my Cannondale Super V. I’m not unfamiliar with play in either the front- or rear wheel. Many bike restorations include removing the play from a bicycle wheel.
The wheels from this bicycle however don’t have a cup and cone style hub, but sealed cartridge bearings, which are must less prone to show side-to-side play.
Worn rear dropouts
Even though initially I thought it had something to do with the bearings, it was only after I’d removed the wheel that I noticed that I was dealing with worn rear dropouts, which is a significantly worse issue.
As it seems, the axle was too short to be fully supported by the frame. So the same force was applied to a smaller area of the frame, causing the axle to slowly eat away the inside of the dropout.
The worn rear dropout must have been an existing issue. Axles don’t shrink and I had hardly ridden the bicycle before noticing the issue. The fact that it’s a mountain bike also means the frame has to deal with more bumps and jolts sustained to the frame, worsening the issue. Or even causing it in the first place.
Repairing the worn rear dropouts
I decided to fill up the worn parts with steel putty from Bison. This is 2-compound epoxy which acts like clay you can mold into place. You need to kneed it for 2 minutes for the compound to be activated before applying it to the surface area.
Step 1. Applying steel putty
After you applied the putty I press it firmly into place using the axle. You want to make sure that there is zero play and using the thing that’s actually going into the dropout is perfect.
Step 2. Smoothing out the dropout surface
I smoothen out the surface afterwards with the skewer
Step 3. Removing excess putty
As a last step I cut away excess parts too clean it up.
And that’s how you repair worn rear dropouts. If you like this article give it a thumbs up. If you have any questions or suggestions for new articles, let me know in the comments below. Cheers.