I posted this thread over in C&V. It deals with the use of frame blocks to repair a crumpled top tube.





The repair seems successful for the most part. The crumpled areas are round save for a dent remaining. The frame block can now be placed around the TT with no gaps showing between the two halves of the block. For the frame repair to be complete (of course the dent would have to be filled), the frame would need to be put on a frame tool similar to a Park HTS-1. Fortunately, I guess, the bend in the TT and DT is gentle and not the usual major bump that one sees in a head on collision.

My question: Assuming the head tube can be straightened and if done correctly, is this frame safe to ride. Or has the crumpling of the TT compromised the tubing integrity that it might fail? I would much rather refinish the TT than redo the whole frame, but the latter is an option if it means I won't get a nasty surprise.

Thanks

I would never ride a bike I had a question about.

You bet your life!
I dont think I would be overly concerned with sudden catostophic top tube failure if this were just the result of a handebar strike dent on the TT. Was there a frontal impact that wrinkled the downtube and pushed bottom of the HT back or is the headtube now twisted out of plane with reference to the seattube? (I dont think use of the HTS-1 would do much for out-of-plane twist).

There was a frontal impact. I believe that was indicated. It is why mentioned the use of the HTS-1. As for HT/ST alignment. One thing at a time. I will worry about that if and when the other problems are resolved. Right now I want to know if the TT, even though "repaired" in a visual sense, is more likely a failure waiting to happen. I am not adverse to having the TT and DT replaced, but would prefer to preserve the frame as much as possible. It is only original once.

I wouldn't feel right suggesting that top tube is safe, and I really don't think the frame jack is a good idea on 531. The idea that you are probably going to want to do more aligning after that's done really would put me off from the whole project. I thought about buying it and replacing the tubes, but it didn't really seem worth it to me.