I noticed the other day that my frame has a crack in it! I believe that it's my seat post causing the problem. A couple of questions really, a) how serious is this? and b) can it be repaired?

crack in seat tube

Edit: I've added a picture of the height of the seat-post to give some extra context on whether or not the frame is too small for me. I've never thought that the seat was crazy high or anything; is it?

seat-height in situ

  • 2
    Can it be repaired? Probably. Is it worth it? Probably not.
    – jimchristie
    Feb 5, 2015 at 1:28
  • I'm guessing the bike is too small for you, so the seat is really jacked up, and the amount of seat post in the seat tube is less than ideal. I'm guessing that's the bottom of the post I see about 1/2" below that dotted "L". Or perhaps the post doesn't even come down that far. If you did not ride with the seat extended so far this would be a minor problem and you could just throw a hose clamp around the tube. But with the seat extended there's too much stress for that. Feb 5, 2015 at 2:54
  • @DanielRHicks I've added a photo to show the height of the seat-post.
    – Matt
    Feb 6, 2015 at 13:10
  • Not jacked up quite as high as I suspected. Where is the bottom end of the seatpost? Feb 6, 2015 at 13:12
  • I can answer that just as soon as I bring a spanner to the bike. I strongly suspect that it's about where that crack is though
    – Matt
    Feb 6, 2015 at 13:37

6 Answers 6


I am going to get beat up for this but steel frames don't fail catastrophically.

Pull that post. If the end of the post is in the middle of the crack then look for a longer post. Get a seat post that extends at least 2" below the bottom of the crack and ideally 4". The post reinforces the frame. Mark the two ends of the crack. If the crack grows stop riding.

I know this is kind of ghetto but put a couple hose clamps on the crack.

That old frame is not really worth a professional repair. But you may be able to get a couple more years out of it.

If that was an aluminum frame I would tell you to throw it away.

  • I agree, basically. But the seat seems to be jacked up pretty far, and a longer post may not be available (or at least uneconomical -- last I looked seat posts were ridiculous). Feb 5, 2015 at 2:56
  • 1
    A fact that he was able to post this question is testimony that steel frames don't fail catastrophically. He came home alive and even the frame is in one piece. This does not mean he should push his luck further. Feb 5, 2015 at 11:02
  • I've stopped riding the bike for the time being, it might just get one more ride out to the shop for someone to look at.
    – Matt
    Feb 6, 2015 at 13:13
  • @Blam I've not yet pulled the tube - I keep forgetting the right spanner. I'll post a photo when I have, thank you.
    – Matt
    Feb 6, 2015 at 13:14

It's hard to tell from the photo ( is that large vertical streak said crack? ), but if your frame is cracked, don't use it. Riding on a cracked frame is risky as it could result in a catastrophic failure / injury / death.

It looks like that's probably a steel frame, so find a local frame builder ( not your buddy who's handy with a welder ), and depending on the damage they may be able to repair it for you.

  • 1
    Yeah, I agree. Would also be worth taking it to your local shop. Once upon a time this would have been standard fare for a bike mechanic, but even if your shop doesn't do welding, I reckon they'll know someone who does. Definitely agree not to ride it in the meantime, though, just think if it gave out under you.
    – PeteH
    Feb 4, 2015 at 19:48
  • Some frame-builder could change the tube but I'd check the inside of the other tubes as well. The cause of the crack might be rust and if that is the case the other tubes might have suffered. Anyway the repair will require a complete stripping and a new paintjob. So a major inspection should come first.
    – Carel
    Feb 4, 2015 at 20:38
  • I have seen those kinds of cracks in two piece aluminum masts and it really looks like some kind of corrosion between the aluminum seat post and steel tube has caused the seat tube to crack. Is the seat post stuck? Feb 4, 2015 at 22:04
  • Yep - it's a steel Dawes Galaxy circa. 1983 with Reynolds 531 tubing
    – Matt
    Feb 6, 2015 at 13:11

Honestly, how much did this bike cost? It looks to be at least 30 years old, judging by the tire and brakes we see in this picture, and even when it was new, I doubt it was worth repairing this kind of damage. The cost of repairing it would be far in excess of buying a new bike.

Now, if you'd spent $1500 on it, even 30 years ago, well, maybe it's worth it. But probably not. My guess is that $300 would have been an excessive amount when it was new, and the bill to repair this crack would be larger than that.


Dawes Galaxy?

Looks like an older model - so a good quality touring frameset - possibly Reynolds tubing.

Anyway, what price do you put on sentimentality? I'm not sure where the idea of long seatpost comes from as the picture doesn't show it. But if you are UK based a company like Argos cycles can easily fix that frame for you. Its a welding job - so the frame could be resprayed and Dawes decals reapplied.

On their website they quote £120 for a seat tube repair but this is a complete replacement of the seat tube. So yours may be different. A full respray is £135.

  • Yeah, it's Reynolds 531 tubing, and I'm not quite ready to give up on it yet! I've considered Argos before for a respray and decals. Maybe this is the perfect opportunity to go for it!
    – Matt
    Feb 6, 2015 at 13:15
  • The Genesis Equilibriums on ebay look particularly good value - if you want to push the boat out a bit .... :-)
    – OraNob
    Feb 6, 2015 at 13:38

A couple of years ago we had a new seat tube fitted to my wifes bike (a 20 year old Claud Butler Lady Dale) after it sheared where it joined the top tube - this was on a step through frame. Fortunately we live close enough to Roberts, one of the few frame builders in the UK, to be able to deliver it. I had to strip the frame for them and it cost about £150. They completely stripped the paint off the frame so we had it powder coated - approx £100.

We did this as she really likes the bike and finds it comfortable for long rides. I don't think that we could get something similar for the price.

If you want to get a new seat tube, you will probably have to send it away. None of the local bike shops would consider it - they make money selling new bikes after all. I think that only Mercian and Roberts offered a quote.

Hopefully this has given you an idea of the costs and what is involved. If you like your bike as it is then it can be a viable option. I suspect that the longer seat post may be the cheaper alternative.


I just fixed mine, I took it to a local welding shop in London, they charged me only £8, it's not pretty but it works fine. I made this little video

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