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Pictures show underneath of top tube. Tube made of 25.4 mm (1 in) Reynolds 531C steel. Rusted through, cleaned a little with file, and most material is still there. Is it worth repairing? Carbon fibre wrap? Epoxy or braze another pipe onto rusted tube? What would make it sufficient to use?

Every other pipe, including BB threads and chain stays are healthy. I would prefer repair it if it makes sense to do so.

Close to head tube Close to head tube close up Middle of top tube

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    Worth the repair is a highly subjective matter and depends on whether you can do it yourself or need a professional and how much you want to spend. This related question might give you some input. Steel certainly isn't the worst material to be repaired, though....
    – DoNuT
    Commented Feb 14 at 13:40
  • I can certainly repair it myself, I was thinking about another 25.4mm cr-mo 1 mm wall pipe, sliced along its longest axis , wrap top tube with fibre glass cloth, soak with epoxy, and then clamp mentioned steel pipe onto it. Is it good idea? Or just use strong epoxy like jb-weld and gluing steel pipe on top tube? I know best would be brazing new top tube, but that is beyond my skillset to do properly.
    – Fosgen
    Commented Feb 14 at 13:53
  • No expertise here, if you are confident you can do and want to save the frame, why not - if you were on a budget, it would probably be easier/cheaper to get a new frame for a few bucks. I'm pretty sure some of the more experienced folks here will soon fill in with an answer...
    – DoNuT
    Commented Feb 14 at 14:16
  • How are you confident the rest of the frame is ok? Commented Feb 15 at 1:24
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    I disasembled bike and jet washed frame inside, BB off, everything. Torch, and no rust inside in all tubes. Sound all other tubes makes sound solid. No scientific method but I feel confident about other tubes health.
    – Fosgen
    Commented Feb 15 at 17:33

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Whether it's worth considering fixing this depends a lot on whether the rest of the frame also has severe corrosion issues, or if the top tube was somehow an outlier. If somehow the rest of it was good and if you wanted to make a project of fixing it, it's certainly possible.

The comment about splitting a 25.4 tube is off base. It would be exceedingly difficult to ever get that tube to wrap neatly around the outside of a 25.4mm top tube. It won't just splay open and conform, it's way too strong for that. The critical missing piece of information here is that .058" wall thickness tubing is the "telescoping size" in the standard succession of 1/8" increment tubing diameters. In other words, a 28.6 tube in 058 telescopes neatly over a 25.4 tube with just enough of a slip fit for brass brazing or many other bonding operations. (.058*25.4=1.47, which is half of 3.2mm, which is 1/8" in metric, plus a good working air gap).

If the top tube were the concern, there's likely a "good" repair here short of replacing the entire tube that involves taking out the bad part and brazing a 28.6 058 sleeve of seamless 4130 over it. That's an easy tube to get, all the 4130 tubing suppliers have it. To do that would either require flexing the cut frame open or also cutting the down tube. The idea of bonding it with epoxy is probably conceptually possible but sounds difficult to get a trustworthy result out of unless you're a pro with light metal composite bonding.

The top tube is probably not the only concern however.

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  • The top tube is probably not the only concern however. Indeed. If the top tube is rusted all the way through, what do the bottom bracket and chainstays look like? How about the fork? Are the ends of the fork about to fall off? I'd be very suspicious of just about any place where water would collect given the top tube's condition. Commented Feb 14 at 21:06
  • Andrew, Nathan, thank you for your input. Top tube was only tube with zero drain, done on purpose? Rest tubes are in good condition, bottom bracket still got threads inside, chainstays, fork, solid. I will proceed with mentioned 28.6mm tube sleeve and high quality metal epoxy. Its bad solution but if it serves me 2 or 3 years I will be more than happy.
    – Fosgen
    Commented Feb 14 at 23:08
  • @Fosgen If you look around on different framebuilders' IGs and Flickrs you'll likely be able to find some examples of sleeve type TT repairs, albeit mostly brazed. Commented Feb 15 at 0:01
  • Just update, epoxied it as discussed earlier. Bend test frame and it broke, with just hands. So it was trash, tube needed to be replaced, debrazed and brazed new tube. Whoever try same, please do it properly, dont glue it.
    – Fosgen
    Commented Apr 1 at 14:44

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