X-Challenge - Broken Sub-Frame

Discussion in 'Thumpers' started by 650x, Jan 24, 2009.

  1. 650x

    650x Long timer

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    A little while ago, was riding the X on a fairly rough road. Was standing up most of the time. Hit a couple of really hard bumps, but think much about it until I sat down. The seat didn't feel right. It felt like it was lower in the rear. Stopped for a look and the whole back end felt loose.

    After limping home, looked for damage. Found this:

    [​IMG]


    [​IMG]



    [​IMG]



    Emailed the pictures to my dealer and called to see if they would cover it under warranty. They told me they would have to have me bring the bike in for them to look at before they would even decide if the warranty would cover it. I offered to pull the sub frame off and send it to them, but they insisted on have the whole bike. With the dealer 250 miles away and looking at at least two or more trips and then they might not ever cover it, decided to repair it myself. :kboom Worthless warranty.

    Pulled the sub frame off and took it to a friend of a friend who happens to be one of the best aluminum welders around. He did a nice job repairing it.


    [​IMG]



    [​IMG]



    Put everything back together today. Decided I needed to add some bracing to the rear of the luggage rack to keep from breaking the sub frame off again. Welded some tabs to the bottom of the luggage rack and built some mounts that bolt to the spots intended for buddy pegs. As soon as I can buy some aluminum channel I will run some from the new tabs on the back of the rack to the new "buddy peg" mounts. This should transfer some of the weight on the luggage rack directly to the lower part of the frame and prevent the sub frame from breaking off again.

    Will try to post some pictures when I get it finished.

    Wondering if anyone else has had problems with the sub frame breaking off?
    It can happen.
    #1
  2. rwamf

    rwamf Follow me

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    No problems here and I always have allot of tools and such in my bag,
    How much weight would you say you had on your rack?
    any pics with it loaded?
    BUMMER, I always worried about that on my 610 but never had a problem either.
    #2
  3. Max Kool

    Max Kool Xtankteam™

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    ^^ +1

    How much weight did you have (roughly) on the rear rack?
    #3
    Stromius likes this.
  4. MaxThePanda

    MaxThePanda Psycho Panda

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    I'm seriously (very seriously) looking at a X and this is probably the issue that worries me most... some people seem to have no problems, but this is at least the second cracked one I've seen. Have you got a picture of the whole subframe you can post?

    How much of a mission do you think it would be to have a replacement fabricated in steel? (Without forking out for the subframe/pannier set from TT... perhaps we can get them to sell us just the subframes? I don't want hard boxes).
    #4
  5. Max Kool

    Max Kool Xtankteam™

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    If you plan to mount a substantial amount of weight onto the rear of the bike riding offroad you should avoid ANY bike with an aluminium subframe.
    #5
  6. MaxThePanda

    MaxThePanda Psycho Panda

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    I suppose the question is "how much is too much". I'm about 90kgs kitted up, and probably won't have more than 30kg extra load in total - say smallish Dirtbagz or equivalent and then a drypack forward on the rack/onto the back of the seat. Fuel in a TT tank - no extra fuel weight on the subframe.

    I'm guessing it should be able to handle that - especially if not charging too hard off road? Bike is rated at 180kg load...
    (really don't want a KLR and can't take the shaking of the 640ADV)
    #6
  7. MZcountryboy

    MZcountryboy Long timer

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    I went for the TT pannier setup, best feature is the new subframe, which BTW fit perfectly.

    When I had the stock subframe off, it felt like you could destroy it with your bare hands. Really flimsy. I plan to do some serious distance touring on mine, so the TT luggage setup was pretty much my only choice.

    TT should offer the subframe seperately, I bet they would sell down the road, after more of the aluminium ones break.
    #7
  8. toycloser

    toycloser Been here awhile

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    Great job on the repair. :clap
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  9. Gregster

    Gregster Been here awhile

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    Nice job on the fix - those are some good looking welds.:clap
    #9
  10. Mtncrzr

    Mtncrzr Just Kidding, not really

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    Yep, that's cracked all right:lol3. Nice job! It appears that you are using the bike for it's intended purpose.

    Good aluminum welds too! Nice reinforcement of the failed weld area.
    #10
  11. Max Kool

    Max Kool Xtankteam™

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    The subframe broke behind the "triangle" of the frame, indicating to me there was load on the subframe behind the point where the two tubes of the subframe are welded together. Typical load like from a duffelbag strapped to the rear rack (and a series of whoops :huh ).

    Too bad mate, but the repair job looks excellent!
    #11
  12. MaxThePanda

    MaxThePanda Psycho Panda

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    Makes me wonder whether it's worth doing some "preventive" bracing and welding to strengthen the subframe in advance... of course that's warranty goodbye, but what's the best case scenario in the event of a break? A new subframe?

    Fat lot of good if it happens when you're hundreds of km from home.

    Will make it a bit heavier, but that's hardly an issue if you're using the bike for travelling...

    Anyone done it yet?
    #12
  13. 650x

    650x Long timer

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    Less than normal, it was only a day trip.

    Will try to find a picture of the actual load and get it posted.

    Don't have a picture of the bare sub frame. sorry

    Am sure after I finish my mods, it won't break again.
    #13
  14. Snuffy

    Snuffy Long timer

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    Bummer on the breakage. Welds look great. Was this failure all at once or do you suppose there might have been a crack that went unnoticed for awhile, then failure? I guess we will have to take a good looksee once in awhile.
    #14
  15. banjopete

    banjopete broke, student, lurker

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    This seems to be such a common failing point on so many bikes it's a shame that the manufacturers aren't picking up on this by now.

    Great work on the fix though, you've gotta love those friends of friends.
    #15
  16. onemoreokie

    onemoreokie Adventurer

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    They went from Aluminium to steel on my 09' X-Country so I guess they (BMW) got the message.
    #16
  17. MaxThePanda

    MaxThePanda Psycho Panda

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    Wonder if it's possible to buy the steel subframe from BMW? It's the same on all the X bikes, isn't it? Seems a bit of a bizarre (marginal) weight saving idea...
    #17
  18. 650x

    650x Long timer

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    It is quite possible there were cracks that may of been unnoticed. The load on the rack was not that much compared to some of the loads it has seen.

    This was only a day trip so all I had in the tail bag, other than my normal tire repair kit, were extra layers due to the possible cold weather that day. More bulk than weight. Here is a picture taken before the 'break."

    [​IMG]


    However, the week before, the bike was loaded down for a long weekend, several hundred mile trip over some very rough and rocky roads.

    [​IMG]


    The stress of that trip may of weakened things and could of went unnoticed. In fact, this whole last summer was one long trip after another with a loaded down packs on the back. Looking back, I had to rebuild the luggage rack due to it breaking. I had to fab new front mounts and add bracing to the luggage rack. In fact, my plan in the event the rack broke again was to add bracing (like I am going to do now) to support the end of the rack by making a sort of triangle support and transfer some of the weight to the lower frame. The rack mounts on the stock sub frame are behind the area where the lower bracing attaches and once you add a rack that sticks out even further, you have a lot of leverage trying to break off the end of the sub frame. Add high speed riding over rough ground and you have the makings of some serious failure. My soon to be completed bracing will (hopefully) solve the issue of the unsupported weight sticking off the end of the sub frame. My only concern now, is what will break next? The main frame?

    I bought the bike to ride and ride it I will. We shall see what happens.
    #18
  19. shardzero

    shardzero I have a bike.....

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    Umm. It's pretty obvious why the subframe broke. BMW does not build luggage for this bike for a reason. Carrying anything so far out on the back will stress the frame for sure. This bike stock is not for touring but enduro.
    #19
  20. rwamf

    rwamf Follow me

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    Yes looking at you load that far back I would be worried, I always move heavy loads forward so it is about half on the seat. I have had 50 lbs with no problems
    But back as far as you show it in the photo would make me very nervous.
    #20