Forum home Commuter cycling forum The workshop

Cracked head tube - safe to ride?

Boneidle24SevenBoneidle24Seven Posts: 44
edited July 2014 in The workshop
Hi,

My question relates to the restoration of an old 1985 Pashley frame. I have been restoring it slowly with the intention of rebuilding it into a vintage style path racer. when I stripped it, I noticed a tiny crack at the very top of the head tube at the rear directly above the top tube. I had it brazed and all seemed well. So then I had it powder coated too and it looked fantastic and like a new frame. When I installed the new headset the crack reopened, about 3-4mm long. I have tried searching the net for advice on whether it is safe to ride a steel framed bike like this without risking a catastrophic failure and the general consensus of opinion would suggest that I trash it. Having just spent rather a lot of money on it I am reluctant. I am also reluctant to have the frame repaired now because the plan was to build a low budget bike. More repairs are just going to make it uneconomical. I may as well have saved up and bought a Pashley Guv'nor.
So do you think a crack like this could result in a major failure? (Probably while I am in heavy traffic or tearing down a hill) Or should I just keep an eye on it. or trash it? Maybe I should sell it on to someone who has the time and money to repair it properly?
Any comments much appreciated.

Posts

  • nicklousenicklouse Posts: 81,520 Lives Here
    If fitting the headset reopened the crack I would not use it.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • Here is a picture of said crack!

    http://thepathracerproject.weebly.com/
  • mr_evilmr_evil Posts: 234
    I'm not surprised it cracked - I see from the photos that the head set cup sits directly in the lug, not supported by the head tube at all! However I am surprised it's lasted since 1985 and not split completely already. It will probably fail at some point, and having watched videos of head tubes separating before, I wouldn't want to be riding it when it happens.
  • deswellerdesweller Posts: 5,271
    Weeellll if it fails it will probably just cause the steerer to flap around a lot. With that in mind I'd probably ride it if I needed the bike as my daily transport - but I would be aiming to replace it pretty quickly.
    - - - - - - - - - -
    On Strava.{/url}
  • Mr Evil wrote:
    I'm not surprised it cracked - I see from the photos that the head set cup sits directly in the lug, not supported by the head tube at all! However I am surprised it's lasted since 1985 and not split completely already. It will probably fail at some point, and having watched videos of head tubes separating before, I wouldn't want to be riding it when it happens.

    Thanks for the comment, although I'm not entirely sure what you mean. The upper race cup is pressed directly into the headtube. the lug completely encloses the headtube. Isn't that how all standard 1" threaded headsets fit on older frames?
  • mr_evilmr_evil Posts: 234
    Usually, the top of the lug is flush with the top of the head tube. That way, the parts which see the most stress are reinforced. It looks like this:
    1267812271400-1krlnaj1aw3dt-700-80.jpg

    With yours, the top of the head tube is some way down from the top of the lug, putting all the force on the lug alone.
    9331131_orig.jpg
  • slowbikeslowbike Posts: 8,498
    If it was mine and the frame was worth it I'd look at putting a collar around the top outside the crack. On the assumption that that will support the tube and stop the crack spreading.
  • Thanks Mr Evil, I understand what you mean now. And yes it's a good point. It does seem odd that they would design it like that. As you can see from the photo, a previous owner has attempted a dodgy weld on it too, which also failed. I quite like slowbike's idea of a reinforcing collar around the top though. that could be a solution.

    Thanks chaps!
  • The RookieThe Rookie Posts: 27,748
    Given where the crack is I'd be inclined to just ride it, it's supported by the top tube. Welding it would of course mean having the whole frame redone!
  • The Rookie wrote:
    Given where the crack is I'd be inclined to just ride it, it's supported by the top tube. Welding it would have course mean having the whole frame redone!

    I may just do that! I've spent enough on the frame already. I want to get on with everything else so I can just ride it. And after all, it's not like I'm planning to ride the Tour de France on it. The original intention was to have it as a play thing for the occasional ride to the pub etc. Once it's up and running, I'll just keep an eye on it and maybe think about fitting a supporting collar at some point, or maybe look out for a replacement frame.
  • MatthewfalleMatthewfalle Posts: 17,380
    So its potentially dangerously cracked, you're (according to the blog) not sure if the forks are safe anyhow and its not actually the frame you wanted in the first place?

    Err, call me silly but I'd get shot and actually get what you wanted before you suffer severe maxillo facial injuries or dead disease and everyone laughs at you.

    Billions of suitable frames kicking around - use this one as a nice ornament and do one that won't kill you.

    But then, that's just me.
    Postby team47b » Sun Jun 28, 2015 11:53 am

    De Sisti wrote:
    This is one of the silliest threads I've come across. :lol:

    Recognition at last Matthew, well done!, a justified honour :D
    smithy21 wrote:

    He's right you know.
  • So its potentially dangerously cracked, you're (according to the blog) not sure if the forks are safe anyhow and its not actually the frame you wanted in the first place?

    Err, call me silly but I'd get shot and actually get what you wanted before you suffer severe maxillo facial injuries or dead disease and everyone laughs at you.

    Billions of suitable frames kicking around - use this one as a nice ornament and do one that won't kill you.

    But then, that's just me.

    When I'm lying in the mangled wreckage with the front wheel where the rear wheel used to be and the shattered head tube through my skull, I hope passers by won't laugh!!

    Point taken and thanks for the comment!
  • rolf_frolf_f Posts: 16,015
    I'd take it to an old school frame builder. They'll know what can and can't be got away with. But I can't quite see how that crack is suddenly going to kill you. Outside of the UK nobody would pay the slightest attention to that!
    Faster than a tent.......
  • The RookieThe Rookie Posts: 27,748
    The crack is on the side of the HT which sees least load (when the front wheel hits a lump or bump it pushes back and pulls the top forwards) the crack is also supported by the top tube, I don't honestly see any chance of a catastrophic failure unless the crack spreads through the HT/TT weld (which you'd see happening), but your call.
  • The Rookie and Rolf F, thank you for your slightly less dramatic opinions. Despite my own reservations about it, I too can't quite see how it would suddenly snap or sheer off so dramatically that it would cause a crash. Being steel isn't it more likely to bend rather than snap? Or I'll see the crack getting bigger. Surely only a frontal impact at high speed with a car (or brick wall) would cause a dramatic failure, and in that situation I'd probably be toast anyway!
  • mr_evilmr_evil Posts: 234
    ...Being steel isn't it more likely to bend rather than snap? Or I'll see the crack getting bigger...
    Steel is very tough, and it could go for years without getting noticably worse, but it's not indestructible and definitely can snap. If the crack was in any other part of the frame then I would say just ride it, but a broken head tube is not good. I found a picture of what appears to be the same frame as yours, with a similar fault.
  • The Rookie wrote:
    The crack is on the side of the HT which sees least load (when the front wheel hits a lump or bump it pushes back and pulls the top forwards) the crack is also supported by the top tube, I don't honestly see any chance of a catastrophic failure unless the crack spreads through the HT/TT weld (which you'd see happening), but your call.

    I'd disagree with your conclusion, all the static and most of the dynamic load would be on exactly this position on the top of the headtube and the reverse at the base. Unless the forks have zero rake and the axle is directly under or behind headtube which is unlikely and would make for interesting handling.
  • Mr Evil wrote:
    ...Being steel isn't it more likely to bend rather than snap? Or I'll see the crack getting bigger...
    Steel is very tough, and it could go for years without getting noticably worse, but it's not indestructible and definitely can snap. If the crack was in any other part of the frame then I would say just ride it, but a broken head tube is not good. I found a picture of what appears to be the same frame as yours, with a similar fault.

    that's an interesting photo Mr Evil, and it does look very similar to my frame. I was just coming around to the idea that it would be ok. Now that photo has changed my mind again. :? It's hanging on my wall right now. I think it may become an expensive ornament, which is a Shame because it looks great! :(

    Arthur Scrimshaw, Indeed you are correct, the head tube is at a very relaxed angle so that the wheel projects way out in front, which is typical I believe of this type of frame. Therefor I guess the load at that point would be greater than normal, which is why it cracked in the first place probably?
  • rolf_frolf_f Posts: 16,015
    Mr Evil wrote:
    ...Being steel isn't it more likely to bend rather than snap? Or I'll see the crack getting bigger...
    Steel is very tough, and it could go for years without getting noticably worse, but it's not indestructible and definitely can snap. If the crack was in any other part of the frame then I would say just ride it, but a broken head tube is not good. I found a picture of what appears to be the same frame as yours, with a similar fault.

    that's an interesting photo Mr Evil, and it does look very similar to my frame. I was just coming around to the idea that it would be ok. Now that photo has changed my mind again. :? It's hanging on my wall right now. I think it may become an expensive ornament, which is a Shame because it looks great! :(

    It needs to be looked at by someone who builds frames. I don't get the impression that any of us on here are going on more than instinct. A frame builder will have seen loads of failed frames and will have a much better idea of what, if anything, will happen if you ignore the issue or how it can be solved if it can't be ignored.

    I'm pretty sure that my local chap would a) be able to make a structural repair that would last and b) be able to repair the paint without it needing to be completely redone.
    Faster than a tent.......
  • The RookieThe Rookie Posts: 27,748
    The Rookie wrote:
    The crack is on the side of the HT which sees least load (when the front wheel hits a lump or bump it pushes back and pulls the top forwards) the crack is also supported by the top tube, I don't honestly see any chance of a catastrophic failure unless the crack spreads through the HT/TT weld (which you'd see happening), but your call.

    I'd disagree with your conclusion, all the static and most of the dynamic load would be on exactly this position on the top of the headtube and the reverse at the base. Unless the forks have zero rake and the axle is directly under or behind headtube which is unlikely and would make for interesting handling.
    The riding load is indeed on that side, but the opposite will see much higher peak loads for the reason given.
  • mr_evilmr_evil Posts: 234
    The Rookie wrote:
    Mr Evil wrote:
    Looks nothing like, failure is different and we don't know who made it, otherwise, yes, just the same!
    It's another failure caused by the weird lugs, and if you bothered to read, it's also made by Pashley.
  • The RookieThe Rookie Posts: 27,748
    If you bothered to read many manufacturers were suggested including Pashley, it was never confirmed who the maker was...nice try at making 2+2=5 though!

    In that case the failure was partly due to the very thin metal around the headset cups but also due to the very poor manufacturing of the lugged head tube to down tube joint, the failure could have been caused by either or a combination of both.
  • mr_evilmr_evil Posts: 234
    The Rookie wrote:
    If you bothered to read many manufacturers were suggested including Pashley, it was never confirmed who the maker was...
    See the last post in that thread.
  • Boneidle24SevenBoneidle24Seven Posts: 44
    edited July 2014
    Looks nothing like, failure is different and we don't know who made it, otherwise, yes, just the same!
    It's another failure caused by the weird lugs, and if you bothered to read, it's also made by Pashley.

    No arguing now chaps!

    I think that the picture of the snapped lug looked very much like mine. However, my frame is a 1985 Pashley Roadster, which I believe only came in black. The snapped one in the pic is green. Unless it had a respray at some point, who knows.

    Anyway dodgy lugs and tubes that are not butted properly doesn't say much for British engineering. I'm guessing that's why our car manufacturing industry died out around the same time!
  • The Rookie wrote:
    The Rookie wrote:
    The crack is on the side of the HT which sees least load (when the front wheel hits a lump or bump it pushes back and pulls the top forwards) the crack is also supported by the top tube, I don't honestly see any chance of a catastrophic failure unless the crack spreads through the HT/TT weld (which you'd see happening), but your call.

    I'd disagree with your conclusion, all the static and most of the dynamic load would be on exactly this position on the top of the headtube and the reverse at the base. Unless the forks have zero rake and the axle is directly under or behind headtube which is unlikely and would make for interesting handling.
    The riding load is indeed on that side, but the opposite will see much higher peak loads for the reason given.

    No I still don't agree with your argument, the point on contact for any 'bump or lump' would have two moments, one backwards but the main force would be directed upwards and given the rake this would produce a higher load on the point of failure.
  • Mr Evil wrote:
    The Rookie wrote:
    If you bothered to read many manufacturers were suggested including Pashley, it was never confirmed who the maker was...
    See the last post in that thread.

    Perhaps he didn't bother to read it? :wink:
  • The RookieThe Rookie Posts: 27,748
    OK fair enough, it is a Pashley (why he couldn't just post in the thread is beyond me!), but the failure mode is totally different none the less as the joint has failed on a frame welded in a different way to this one.
Sign In or Register to comment.