Almost done with a road frame I've been working on for a little while, back-porch-jigless-after-work project. Its actually come out really well so far. However, I brazed on the chainstay bridge this afternoon and forgot to throw on my dummy axle before getting started. My rear spacing went from 130 to 126. Must have been some shrinkage. Everything is still well aligned.
Do I remove the chainstay bridge and redo it with the dummy axle in place?
Or do I just cold set the thing?
I am guessing cold setting it would be the lesser of two evils in terms of chainstay integrity. Opinions?
I don't think you can hurt anything by cranking up the torch and heating the outside of the stays a little. Everyone that has built a steel bike has seen the rear triangle shrink because of the bridges. Nowadays I heat the outside of the stays opposite the bridge as a last step.
thanks for the links, here is the video, witch-wanding starts at 3:18
Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Raleigh Pro, Trek Cycle Cross, Mongoose tomac ATB, GT Bravado ATB, JCP Folder
Stays always pull inwards after bridges are installed. Many will over space their axle width by about 5mm in anticipation of this. Using the torch to thermally move the stays will work, as well as simply bending them out. Andy.
I'd try to witch wand it. There was a video of someone aligning a bike using witch wanding posted here not all that long ago
Steel shrinks on the side that was heated. In the future, you should also heat the outside of the chain stays. You don't have to get them red
Went out there and hit the outsides of each chainstay with the torch along a 6 inch section adjacent to the chainstay bridge. Heated it to just barely red as in the video. Spacing is now perfect again. Awesome! Thanks!