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  1. #1
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    Broken MKIII frame - how have you tried to fix it?

    I've read here and there about people who have tried and sometimes failed to fix their broken rear triangle. Like the rider who welded a sheet of metal that covers the whole drive side. And the guy who tried to weld a fix twice and both failed. I know a guy who'd be willing to weld mine if and when the day comes, but I need some insight on what kind of fix to pursue. I figured I might as well start gathering that info while the bike's still good.

    So I'd like to hear what fixes you've tried, about when it was done, and how well/long it held up.
    Life is a bowl of fruit, and I am trying to not bite into the mold.

  2. #2
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    Take off your stock triangle now (before it is broken) and take it to a guy who can make one out of steel. That pretty much guarantees that the stock one will never ever break.
    -F

  3. #3
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    I believe I am "that rider who welded the plate" in there and it is still going strong.

    No camera for pictures for now, sorry.

    but holding together like a champ.

    i smell a rat-Patrick Henry

  4. #4
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    Just checked my MKIII after today's ride and the rear is cracked all the way thru. I know a guy who'll take a shot at welding some reinforcements on. Well, after he gets a better look at it.
    Life is a bowl of fruit, and I am trying to not bite into the mold.

  5. #5
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    has anyone with a broken rear triangle, or for that matter with a new rear triangle,
    tried gluing (with epoxy) an aluminum plate on the whole drive side, kinda like
    skott160 did, but gluing instead of welding.
    i was talking to a friend last week who builds and works on ultralights. showed him
    my bike(mkiii), the rear triangle, and pics of the cracks from this site. he thought that
    gluing with epoxy would be better than welding. i am one of the people with a cracked
    rear triangle(same spot as everyone else).picked up a new rear triangle, and am thinking of reinforcing it in some way, before the new one cracks. also would like to try fixing the
    broken triangle i have sitting here. i might take his advice and try the gluing method. he was pretty confident it would work, and work better than welding.
    let me know your thoughts on this method????
    peterv

  6. #6
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    Quote Originally Posted by peterv
    has anyone with a broken rear triangle, or for that matter with a new rear triangle,
    tried gluing (with epoxy) an aluminum plate on the whole drive side, kinda like
    skott160 did, but gluing instead of welding.
    i was talking to a friend last week who builds and works on ultralights. showed him
    my bike(mkiii), the rear triangle, and pics of the cracks from this site. he thought that
    gluing with epoxy would be better than welding. i am one of the people with a cracked
    rear triangle(same spot as everyone else).picked up a new rear triangle, and am thinking of reinforcing it in some way, before the new one cracks. also would like to try fixing the
    broken triangle i have sitting here. i might take his advice and try the gluing method. he was pretty confident it would work, and work better than welding.
    let me know your thoughts on this method????
    peterv
    The folks in the industry say "bonding" instead of "gluing"

    I am watching this thread because I feel like the clock is ticking on my MKIII.

    Did your friend specify epoxy, JB Weld, or some other kind of aluminum-filled putty? I think finding the most compatible adhesive would yield the best results (search "Devcon"). This sounds like a good idea, esp. if you do it before it cracks.

    It would have that retro aero look too.


    I may actually try this.

    -F

  7. #7
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    ok......bonding, gluing, sticking....or whatever....go go, ga ga ..........
    i have a past degree in plastics (a previous life), so i probably know just
    enough to be dangerous!!!!!
    there are lots of different resins......but he was talking a 2 stage...hardener + resin......
    he mentioned no specific brand......
    i'm currently on a work assignment in vegas till may, so i cant approach this task
    until i get home......
    right now lookin for other peoples thoughts....... anyone know what type of aluminum,
    thickness, and where to pick up??
    thanks
    peterv

  8. #8
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    Quote Originally Posted by peterv
    has anyone with a broken rear triangle, or for that matter with a new rear triangle,
    tried gluing (with epoxy) an aluminum plate on the whole drive side, kinda like
    skott160 did, but gluing instead of welding.
    i was talking to a friend last week who builds and works on ultralights. showed him
    my bike(mkiii), the rear triangle, and pics of the cracks from this site. he thought that
    gluing with epoxy would be better than welding. i am one of the people with a cracked
    rear triangle(same spot as everyone else).picked up a new rear triangle, and am thinking of reinforcing it in some way, before the new one cracks. also would like to try fixing the
    broken triangle i have sitting here. i might take his advice and try the gluing method. he was pretty confident it would work, and work better than welding.
    let me know your thoughts on this method????
    peterv
    There was, I can't say if this exact still exists though, a Cement called MarineTex. http://www.marinetex.com. It's sole purpose was to allow a Nautical Vessel with a cracked Engine Block to seal up, stop weeping oil, and maintain compression to return to Land.
    But by no means could you race the engine or keep using it to save money.
    I cannot see this material having any use with a structure like a Bicycle.

  9. #9
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    We have used the liquid form of this stuff at work - tough stuff!
    The putty form would probably work best on a frame.



    http://www.devcon.com/products/produ...1&familyid=107

    Tech. specs:
    http://www.devcon.com/prodfiles/pdfs/fam_tds_107.pdf
    Sounds like surface prep is key, and don't feather it out into thin layers.

    It's a $60 experiment, but it's twice as strong as plain old epoxy, which is only about $15.
    Order here.
    I would be more inclined to try it if my bike was already broken. Any guinea pigs out there?

    -F

  10. #10
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    just a thought..would it be possible to do a carbon/kevlar wrap repair? wrap the upright and chainstay tubes like a bandage?maybee do it before the cracks appear?.

    My mk3 is having a rest while i try out another bike,but i can foresee the day when i'll need to repair it as i broke the mainframe and rear triangle on my previous mk3.

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    Quote Originally Posted by peanuts
    just a thought..would it be possible to do a carbon/kevlar wrap repair? wrap the upright and chainstay tubes like a bandage?maybee do it before the cracks appear?.

    My mk3 is having a rest while i try out another bike,but i can foresee the day when i'll need to repair it as i broke the mainframe and rear triangle on my previous mk3.

    peanuts

    my friend said it would be stronger/better to use a plate bonded to the frame
    (drive side), like skott166 did, only bonded, not welded...

    peterv

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    Quote Originally Posted by Fleas
    We have used the liquid form of this stuff at work - tough stuff!
    The putty form would probably work best on a frame.



    http://www.devcon.com/products/produ...1&familyid=107

    Tech. specs:
    http://www.devcon.com/prodfiles/pdfs/fam_tds_107.pdf
    Sounds like surface prep is key, and don't feather it out into thin layers.

    It's a $60 experiment, but it's twice as strong as plain old epoxy, which is only about $15.
    Order here.
    I would be more inclined to try it if my bike was already broken. Any guinea pigs out there?

    -F
    fleas....

    with this devcon aluminum putty that you suggest trying....
    are you thinking, applying it directly to the frame tubes, or
    using the putty to bond a plate to the drive side, like skottt160 did?
    peterv

  13. #13
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    I say this is not going to work like a normal rear Triangle. Sure it will keep this one in a working-form, it will surely fail in time soon. Just because some tubes of metal are welded and formed does not mean they have no movement designed into them. Whatever flex is being erradicated will only be transfered to another point in the structure, if this placebo-resin does not work itself loose to show. Who had tried using 'The Frame Doctor' from VINTAGEBMX.COM?

  14. #14
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    Quote Originally Posted by Uncle Jemima
    I say this is not going to work like a normal rear Triangle. Sure it will keep this one in a working-form, it will surely fail in time soon. Just because some tubes of metal are welded and formed does not mean they have no movement designed into them. Whatever flex is being erradicated will only be transfered to another point in the structure, if this placebo-resin does not work itself loose to show. Who had tried using 'The Frame Doctor' from VINTAGEBMX.COM?

    .....what if small aluminum plates were only used in the corners, where the
    tubes are welded together? would this provide added strength, and still
    allow some flex of the tubes?

  15. #15
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    Quote Originally Posted by peterv
    .....what if small aluminum plates were only used in the corners, where the
    tubes are welded together? would this provide added strength, and still
    allow some flex of the tubes?
    Try this: take a Pencil and with opposed finger, and then your thumb, hold its middle. You should be able to have equal leverage while rocking it between your pinched fingers. Move closer to an end,of the Pencil will increase leverage of the longer part; and leverage at the secured end decreases. So while patching the junctures and runners with gussets and boxxing, you are only transfering a load to another area of the structure. Since the other side of the Back-Half is not fashioned the same, that would be the next failure. Choice of metal and how is is shaped is quite the large and important factor in having a compliant riding Bike. How often have you read of a compliant and comfortable Road Bike frame, compared to another of similar size and construction?
    Last edited by Uncle Jemima; 04-09-2010 at 08:31 AM.

  16. #16
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    Quote Originally Posted by peterv
    fleas....

    with this devcon aluminum putty that you suggest trying....
    are you thinking, applying it directly to the frame tubes, or
    using the putty to bond a plate to the drive side, like skottt160 did?
    peterv
    Use the Devcon to bond the plate to the frame tubes.

    And Uncle J makes a sound point about the point of failure just getting re-located by reinforcing the problem areas. My thought is that the problem areas are weak for some reason, and I'm hoping that the stress will be transferred to an area that is strong enough to take it, like the middle of the frame tube instead of the weld junctions. Sure, the stress will increase in that area, but I think it is strong enough. And by bonding instead of welding, we haven't changed the properties of the frame tube. I actually think smaller triangles would work, while a full plate would be overkill. Easier to fit, too.

    -F

    PS -
    Quote Originally Posted by peanuts
    just a thought..would it be possible to do a carbon/kevlar wrap repair? wrap the upright and chainstay tubes like a bandage?maybee do it before the cracks appear?.
    IMHO I think this applies better to something that's broken in the middle, not where multiple tubes are joined. But I suppose you could wrap a reinforcement/triangle into it.

  17. #17
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    Quote Originally Posted by Uncle Jemima
    Try this: take a Pencil and with opposed finger, and then your thumb, hold its middle. You should be able to have equal leverage while rocking it between your pinched fingers. Move closer to an end,of the Pencil will increase leverage of the longer part; and leverage at the secured end decreases. So while patching the junctures and runners with gussets and boxxing, you are only transfering a load to another area of the structure. Since the other side of the Back-Half is not fashioned the same, that would be the next failure. Choice of metal and how is is shaped is quite the large and important factor in having a compliant riding Bike. How often have you read of a compliant and comfortable Road Bike frame, compared to another of similar size and construction?
    ......hmmm......nice explanation......you make a very good point.

  18. #18
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    Quote Originally Posted by peterv
    ......hmmm......nice explanation......you make a very good point.
    You're not being sarcastic are you? Even though it is not a wheel which has a center to opertate about, forces upon a lever (Chain-Stay for instance) will act in the same manner. With more center material, gussets and the like at the Dropout, a Torque-Vector will only move further down this lever-length until acting upon gravity and rotation.

    Which brings a much more difficult question to mind when Builders and Tuners are fabbing and creating structures like these for our Bicycles:

    A Spoked wheel will exhibit a Torque-Vector (moment of Inertia) in an Upward Moment. Yet a Disc Wheel will exhibit the very same measured Moment, yet in a downward vector. So with a complete unit like a 6POINT back-half as opposed to all these broken Mark3 parts, how would it display torsion and memory standards if they could very well act upon Upward and Downward moments???

    Where's Kapusta?

  19. #19
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    Quote Originally Posted by Uncle Jemima
    Who had tried using 'The Frame Doctor' from VINTAGEBMX.COM?
    I was in contact with several establishments who claimed they did frame repair, including him I believe.

    I could find none online who were interested in attempting a repair.

    I did not search very hard, however.
    i smell a rat-Patrick Henry

  20. #20
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    Quote Originally Posted by Uncle Jemima
    You're not being sarcastic are you? Even though it is not a wheel which has a center to opertate about, forces upon a lever (Chain-Stay for instance) will act in the same manner. With more center material, gussets and the like at the Dropout, a Torque-Vector will only move further down this lever-length until acting upon gravity and rotation.

    Which brings a much more difficult question to mind when Builders and Tuners are fabbing and creating structures like these for our Bicycles:

    A Spoked wheel will exhibit a Torque-Vector (moment of Inertia) in an Upward Moment. Yet a Disc Wheel will exhibit the very same measured Moment, yet in a downward vector. So with a complete unit like a 6POINT back-half as opposed to all these broken Mark3 parts, how would it display torsion and memory standards if they could very well act upon Upward and Downward moments???

    Where's Kapusta?
    uncle jemima,
    ...no, i was not being sarcastic at all .....your posts are very informative, and
    help me out.....thanks

  21. #21
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    Unfortunately, Skottt from Vermont, this is most likely due to the Failure-Types and not as what capacity 'The Frame Doctor' has as a provider of services. You say to have taken a better look at what is offered, and if you know the SE Bicycles name and brand, you can see that there is quite the demand for them. Just outward-appearances show these MKIII bikes to have been over-ridden to failure, and dare-I-say with the expectation of an unlimited supply of replacement-parts.

    A very good friend of mine was at a time a strong mark as an Iron Horse retailer; there are a few MKIII broken back-halfs on record. Most notable was a DW-LINK'd model that broke only as a 6-7' very aggressive drop-off was factored into a routine. Up until this, the bike and rider were very capable for how it was shown to be ridden. The base-model after all was never offered with a then revolutionary 20mm Thru-Axle; that speaks volumes.

    If this is taken as 'attitude' or something to be Inflikted towards MarkIII owners, I am sorry for the confusion. It is not my intent or a result I am trying to achieve.

  22. #22
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    Quote Originally Posted by Uncle Jemima
    Who had tried using 'The Frame Doctor' from VINTAGEBMX.COM?
    If you mean this guy:

    http://www.theframedoc.com/

    I talked to him, and he does not seem to be interested in these repairs.

  23. #23
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    Quote Originally Posted by Uncle Jemima
    The base-model after all was never offered with a then revolutionary 20mm Thru-Axle; that speaks volumes.
    .
    Some MKIII models came stock with a 20mm TA Pike.

  24. #24
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    Quote Originally Posted by Uncle Jemima
    Unfortunately, Skottt from Vermont, this is most likely due to the Failure-Types and not as what capacity 'The Frame Doctor' has as a provider of services. You say to have taken a better look at what is offered, and if you know the SE Bicycles name and brand, you can see that there is quite the demand for them. Just outward-appearances show these MKIII bikes to have been over-ridden to failure, and dare-I-say with the expectation of an unlimited supply of replacement-parts.

    A very good friend of mine was at a time a strong mark as an Iron Horse retailer; there are a few MKIII broken back-halfs on record. Most notable was a DW-LINK'd model that broke only as a 6-7' very aggressive drop-off was factored into a routine. Up until this, the bike and rider were very capable for how it was shown to be ridden. The base-model after all was never offered with a then revolutionary 20mm Thru-Axle; that speaks volumes.

    If this is taken as 'attitude' or something to be Inflikted towards MarkIII owners, I am sorry for the confusion. It is not my intent or a result I am trying to achieve.
    As I have said before,

    A. I bought my frame used, from a third party. I never expected nor attempted anything warantee oriented.

    B. These are the thru axles I am abusing the bike with.
    i smell a rat-Patrick Henry

  25. #25
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    So are we saying that reinforcing the cracked area isn't gonna do it cuz it's likely to break somewhere else? Would triangular gusset plates at the forward corners be enough, or is the rear triangle likely to break mid-tube?

    My other thought was to line the triangles on the drive and non-drive sides with a second triangle. Skottt160's solution looks sturdy, but having the triangle filled in seems more than what's needed. So I might follow his lead, but use thicker metal to compensate for what I'm removing from the center.

    Option 3 might be to add to the rear triangle on the drive side, extending it down to match the shape on the non-drive side. The question is, is having the triangle wrap over the chain part of the problem? If so, then modifying the shape might relieve some of the excess stresses?

    I have like a week before my welder gets the frame to sort out a plan. I think he was leaning towards the forward corner reinforcements, after he fixes the crack.

    P.S. I noticed a good amount of tire rub on the non-drive side. So going to the RWS should help with this as well as the triangle flex issue? I currently have an XT skewer.
    Life is a bowl of fruit, and I am trying to not bite into the mold.

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