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  1. #1
    Join Date
    Nov 2011
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    1,805

    Cracked head tube

    My jake the snake head tube cracked. I know I know, the frame is done, but this is 2021 mad max bikes edition. It's very hard to find a bike and prices are ridiculous. I am looking for ways to squeeze a few more months out of it.

    Options?
    1. Shaft collar?

    2. Wrap the head tube in g-flex + fiberglass? Dunno if this would help much with the crack progressing, but I hope it would prevent a sudden catastrophic failure.
    3. ...?

  2. #2
    Join Date
    Dec 2007
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    Hell Track
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    10,710
    You're gonna want this:



    plus this:


  3. #3
    Join Date
    Aug 2018
    Location
    Cackalacky
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    2,990
    thought this was about a crackhead in a tube.
    you don't want no smoke.

  4. #4
    Join Date
    Sep 2009
    Location
    in the trench
    Posts
    13,018
    Looks like the crack starts to splay at the top of the bottom cup. Don't do it. Im sure someone has something safer laying around

    Sent from my SM-G950W using TGR Forums mobile app

  5. #5
    Join Date
    Nov 2005
    Location
    Down In A Hole, Up in the Sky
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    30,422
    See my username.

    Seriously, I doubt things would end in catastrophic failure before you had a chance to get off of your bike. Does it creak/etc when you ride it now?
    Forum Cross Pollinator

  6. #6
    Join Date
    Mar 2008
    Location
    northern BC
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    24,195
    JB weld ductape WD 40

    but seriuosly maybe talk to the mfger
    Lee Lau - xxx-er is the laziest Asian canuck I know

  7. #7
    Join Date
    Nov 2011
    Posts
    1,805
    Yes the crack splays.

    There is no slack or clicking.


    Anyone ride the carbon jake frames? Are they worth the price jump?

  8. #8
    Join Date
    Nov 2011
    Location
    Elmore, VT
    Posts
    1,072
    Drill tiny holes at the ends of the crack, that can help it from propagating.
    Then Fiberglass.
    If they can build bikes out of bamboo you should be able to keep it running for a bit.

  9. #9
    Join Date
    Nov 2008
    Location
    between campus and church
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    7,555
    Contact Kona. Then report back.

  10. #10
    Join Date
    Sep 2009
    Location
    in the trench
    Posts
    13,018
    Kona are generally good with warrantee and crash replacement. That'd be worth a try

    Sent from my SM-G950W using TGR Forums mobile app

  11. #11
    Join Date
    May 2012
    Location
    san diego
    Posts
    2,572
    Further point to add - bike co's seem to be holding separate inventory to take care of warranty claims. So even if this doesn't qualify it may be possible you could score a crash replacement from said stock, even if regular stock is out.

  12. #12
    Join Date
    Feb 2013
    Posts
    1,481
    Quote Originally Posted by rideit View Post
    See my username.
    By that logic we also should be waiting for Ill-Advised-Strategy to make a post too. I vaguely remember him fixing up a seatstay of a scooter with fiberglass tape? A little less sketchy then a cracked headtube.

  13. #13
    Join Date
    Oct 2003
    Location
    Banff
    Posts
    21,357
    any local welders? might be able to do a wrap around the crack that comes back to the downtube?


  14. #14
    Join Date
    Nov 2005
    Location
    Down In A Hole, Up in the Sky
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    You would probably have to re-heat treat the frame with a weld like that. I guess my point is that will give you some horrendous feedback before it catastrophically fails, IMO. I wouldn’t go trying to get downhill KOM s, but I would certainly still take it for a spin until it really cracks.
    Forum Cross Pollinator

  15. #15
    Join Date
    Mar 2008
    Location
    northern BC
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    24,195
    Jakes come in Carbon altho its unclear what this is?

    depending on if its carbon or not the warranty is different

    https://konaworld.com/warranty/
    Lee Lau - xxx-er is the laziest Asian canuck I know

  16. #16
    Join Date
    Dec 2007
    Location
    Hell Track
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    10,710
    Quote Originally Posted by rideit View Post
    You would probably have to re-heat treat the frame with a weld like that. I guess my point is that will give you some horrendous feedback before it catastrophically fails, IMO. I wouldn’t go trying to get downhill KOM s, but I would certainly still take it for a spin until it really cracks.
    ...Maybe?

    I've only snapped off one head tube in my time, but it was almost completely without warning. I was lucky that it happened on a very minor bunny hop in a parking lot and it held on by a sliver of metal at the top tube that didn't detach.

    If I'd been at full speed on a trail, it would've sucked. A lot.

    I've seen steerer tubes rip out the front of a head tube through cracks that look like op's. Maybe he could limp it along for a bit. But if that thing fails, there's a 99% chance that it'll be the worst fucking crash OP has ever taken. Cracked headtubes and cracked handlebars are two things that aren't worth gambling with.

  17. #17
    Join Date
    Nov 2005
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    Down In A Hole, Up in the Sky
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    Fair enough.
    Burn it with fire, and nuke the remains.
    Forum Cross Pollinator

  18. #18
    Join Date
    Aug 2002
    Posts
    1,723
    No way I'd be riding that more than to a neighbors house. Yeah may not fail catastrophically but if it does that's gonna be a major problem. Have an old steel Salsa Mariachi frame that I retired b/c it has a smaller crack than that in the downtube right on a gusset and this has way more potential for failure.

    Contact Kona, if that doesn't work there are still frames to be found right now, even if it's a hold-over frame.

  19. #19
    Join Date
    Oct 2002
    Location
    Shadynasty's Jazz Club
    Posts
    9,294

    Cracked head tube

    Quote Originally Posted by toast2266 View Post
    But if that thing fails, there's a 99% chance that it'll be the worst fucking crash OP has ever taken. Cracked headtubes and cracked handlebars are two things that aren't worth gambling with.
    I’m surprised the discussion made it beyond this. I wouldn’t ride that thing down the block.
    Remind me. We'll send him a red cap and a Speedo.

  20. #20
    Join Date
    Nov 2011
    Posts
    1,805
    It's 7005 aluminum, apparently no need to heat treat it. Any recs for a van area welder?

    Kona only open thursday to friday. I will drop by, but the frame is 2012.

    Looking at youtube it seems I misinterpreted "CX". I thought CX meant 90s rigid MTB with drop bars on green trails.

  21. #21
    Join Date
    Nov 2011
    Posts
    1,805
    Anyone try the knolly cache steel? Looks like an amazing bike especially for doing what I should not have been doingwith the JTS. But, how is it on the road? I hang with some pretty fast road bikes and the JTS was no slough.

  22. #22
    Join Date
    Nov 2005
    Posts
    5,435
    Quote Originally Posted by Cocximus View Post
    It's 7005 aluminum, apparently no need to heat treat it. Any recs for a van area welder?
    7005 was typically heat treated to a t5 condition, which is much easier in production than t6, but that's still heat treatment, despite how the final step was often combined with powder coating (which lead to a lot of over-simplified descriptions in bike press). The material properties compared to as-welded are pretty different, though, like almost 5x the yield strength. I would not go this route.

  23. #23
    Join Date
    Nov 2010
    Location
    Montrose, CO
    Posts
    3,332
    Its a nine year old bike that it sounds like you've rode hard. Its new bike time.

  24. #24
    Join Date
    Dec 2007
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    Quote Originally Posted by Cocximus View Post
    It's 7005 aluminum, apparently no need to heat treat it. Any recs for a van area welder?
    7005 doesn't need a complicated heat treating process, but it still needs to go through a couple stages in an oven at various temps. The temps are relatively low, so that makes it easier. But it's still probably gonna ruin the paint on the rest of the bike.

    (Edit: Jono beat me with actual info)

  25. #25
    Join Date
    Mar 2008
    Location
    northern BC
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    Quote Originally Posted by snowaddict91 View Post
    Its a nine year old bike that it sounds like you've rode hard. Its new bike time.
    this ^^ if OP has good components maybe they will go on another used frame

    Vangroovy should be a great place to pick up a used frame,

    if you talk nice to Kona maybe they help you out for cheap $

    but trying to weld aluminium could do all kinds of shit to a compromised pretty important joint

    I wouldn't fix it
    Lee Lau - xxx-er is the laziest Asian canuck I know

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