Recently two different frames came through the shop with broken right rear dropouts. Usually, it’s a pretty straightforward repair. The best way to approach it is to source an identical part and then simply replace it. Sometimes that’s not possible so a little creativity is required.
The first frame was a Miyata. It had Shimano SF dropout like many good quality Japanese frames from the 1980’s. I found a full set (fronts and rears) on Ebay and got them on the way. The fronts will go on the shelf and eventually be used on a new fork, the extra left rear one will probably languish there forever.
The broken dropout is removed by first cutting it in half to separate the part that attaches to the seat stay from the part that attaches to the chain stay. Each piece is then heated with the torch until the brazing material holding it in place melts and it can be gently pulled free. After the stays cool down, they get sanded carefully to remove old brazing material, and any old paint or grime that didn’t burn off during the removal process. The new dropout is sanded to expose clean bare metal, inserted into the frame, alignment is checked carefully, and then it’s brazed in place. After it cools down again, a little filing and sanding is needed. The idea is to make it look exactly as it did before so after repainting no one will ever know the bike was repaired. This one went well and was done in less than an hour, even including time for things to cool down. The frame is now at the powder coat shop getting a new color and a fresh set of decals. Here’s a photo of the new dropout:
The next repair was an old Gitane. This particular frame has very rare dropouts that were only used by Gitane for a year or two, and were unique to the brand. I emailed a few friends to see if anyone had a damaged Gitane frame with those dropouts- if they did, I could have cut the stays and harvested the intact dropout. It was a long shot and of course and I wasn’t able to find a replacement.
There are a couple options left to the builder in a situation like this. The best is usually to replace both dropouts. In this case, a repair was preferred in order to preserve the look of the frame. The problem with a repair is that the part which broke is still there, along with all the accumulated fatigue that caused it to break in the first place. Here’s what the dropout looked like when the frame was brought in:
First, I filed away the raised face around the axle slot on each side of the dropout, and carefully filed and sanded away all the chrome. At the two points where it was broken, I filed away material at a 45 degree angle all the way around each break. Then I TIG welded the broken spots and filed them down until they were invisible. I could have stopped there, but as I mentioned earlier, there is still fatigued material on each side of the repair. To reinforce the area, I brazed a thin sheet of steel over each face of the dropout and cut to match the shape. The repair is visible, but you have to look very closely.
The customer sourced a complete new set of decals and chose a color. It would be possible to have the old chrome stripped and redone, but expensive. Instead, we elected to coat the previously chromed areas with a shiny silver powder coat.
While the frame was in the capable hands of my friends at Forever Powdercoating, we evaluated which of the old components we would reuse, and which we would replace. In the end, only the handlebar, stem, seat, seatpost, and brakes were kept. The rest of the new parts were either ordered in, or supplied by the customer. I built a new set of wheels and had everything waiting and ready to install as soon as the frame was ready.
Nearly 36 years to the day after he got the frame for his 16th birthday, James got his bike back looking like new.