Advertise on Bikeforums.net



User Tag List

Page 1 of 2 12 LastLast
Results 1 to 25 of 27
  1. #1
    Senior Member
    Join Date
    May 2008
    Location
    NORCAL
    Posts
    102
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    what are the chances of frame snapping...

    so for you trail riders out there what are the chances of a frame snapping where the steerer inserts into the frame? like this:
    http://www.youtube.com/watch?v=6UmaZ...layer_embedded

    ive seen way too many videos of this stuff. but its not like i hop rocks or anything. tons of vids like this!

  2. #2
    Senior Member yellowjeep's Avatar
    Join Date
    Aug 2005
    Location
    Lawrence
    Posts
    3,267
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Slim
    When in doubt, style it out.

    How to post full size pictures

  3. #3
    Svr
    Svr is offline
    Senior Member Svr's Avatar
    Join Date
    Dec 2005
    Location
    Atlanta, GA
    Posts
    1,223
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    There are an enormous amount of variables, but....

    If you "case" a jump by landing wrong, like the rider in the video, while riding a frame never designed to survive that type of landing, failure of the frame is almost guaranteed.

    The junction of the downtube and head tube is the most likely failure point on a bicycle frame.

  4. #4
    In search of moar cowbell dminor's Avatar
    Join Date
    Oct 2004
    Location
    The 509
    My Bikes
    1971 Suzuki TS125/ factory race kit/AHRMA-legal; 1969 Suzuki TS250/factory race kit; 1967 Suzuki K-15 Hillbilly Trail 80; 1977 Yamaha IT175; 1964 VanTech Scrambler racing frame
    Posts
    12,139
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Svr View Post
    There are an enormous amount of variables, but....

    If you "case" a jump by landing wrong, like the rider in the video, while riding a frame never designed to survive that type of landing, failure of the frame is almost guaranteed.

    The junction of the downtube and head tube is the most likely failure point on a bicycle frame.
    I would say that your first statement is correct and the last two statements are false.

  5. #5
    Senior Member
    Join Date
    May 2008
    Location
    NORCAL
    Posts
    102
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by dminor View Post
    I would say that your first statement is correct and the last two statements are false.
    and your defense would be...?

  6. #6
    Svr
    Svr is offline
    Senior Member Svr's Avatar
    Join Date
    Dec 2005
    Location
    Atlanta, GA
    Posts
    1,223
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by dminor View Post
    I would say that your first statement is correct and the last two statements are false.
    Based on what?

    Why is the most likely location for a gusset on an MTB frame placed between the head tube and downtube?

    Because...


  7. #7
    In search of moar cowbell dminor's Avatar
    Join Date
    Oct 2004
    Location
    The 509
    My Bikes
    1971 Suzuki TS125/ factory race kit/AHRMA-legal; 1969 Suzuki TS250/factory race kit; 1967 Suzuki K-15 Hillbilly Trail 80; 1977 Yamaha IT175; 1964 VanTech Scrambler racing frame
    Posts
    12,139
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by kaitanium View Post
    and your defense would be...?
    Quote Originally Posted by Svr View Post
    Based on what?

    Why is the most likely location for a gusset on an MTB frame placed between the head tube and downtube?

    Because...

    Let's examine the original statement: "The junction of the downtube and head tube is the most likely failure point on a bicycle frame." It is not any more because of what you just said in your follow-up: that this is the spot that frame makers gusset and reinforce the most robustly. So, yes, it is one of the most highly-stressed points on a bicycle frame but product-liability precautions in that area mean that a frame will most likely fail more toward the middle of the downtube or top tube or anywhere a suspension mount (in the case of FS) has been welded on.

    On a more technical note, the picture you supply shows a frame that did not fail at the juncture - -it failed in the manipulated tube behind it.

    Now, backing up to your second statement: ". . . while riding a frame never designed to survive that type of landing, failure of the frame is almost guaranteed." I say that is false because this is a totally unqualified statement. If I case ONE landing like that on an X-mart bike, I'm almost guaranteed that it will fail catastrophically? Not that, maybe, over time of such abuse, that it is likely that the frame could be weakened to the point of eventual failure?

    I'm nit-picking you for a reason. People come on here all the time and make ill- or half-informed blanket statements like that and I just decided I'm tired of seeing this stuff get thrown out here unchallenged. You might think I'm splitting hairs but I'm just making a case for a little accuracy.

    BTW, your first stement was true: "There are an enormous amount of variables . . ." There are. That's why it's wise to not make sweeping statements that don't hold up.

  8. #8
    Svr
    Svr is offline
    Senior Member Svr's Avatar
    Join Date
    Dec 2005
    Location
    Atlanta, GA
    Posts
    1,223
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by dminor View Post
    On a more technical note, the picture you supply shows a frame that did not fail at the juncture - -it failed in the manipulated tube behind it.
    The pictured frame failed at the down/head tube junction in the HAZ (Heat Affected Zone) of the weld. It's the weakest point of any welded aluminum joint.

    The cause: Rider error.

    MTB frames are not indestructable unless they're built to withstand the abuse of dirt jumping or "slope style". Landing 50/50 (one wheel on the landing slope, one wheel off) will cause a frame to fail. As the OP mentioned, this type of failure is well documented.

    Want your frame to last "forever", (or nearly forever)? Don't crash.

  9. #9
    You gonna eat that? Doohickie's Avatar
    Join Date
    Sep 2008
    Location
    Fort Worth, Texas Church of Hopeful Uncertainty
    My Bikes
    1966 Raleigh DL-1 Tourist, 1973 Schwinn Varsity, 1983 Raleigh Marathon, 1994 Nishiki Sport XRS
    Posts
    13,936
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    The reason you see so many videos like that is that most x-mart bikes have that little decal that reads "NOT FOR OFF ROAD USE". They're just not built for it.
    I stop for people / whose right of way I honor / but not for no one.



    Originally Posted by bragi "However, it's never a good idea to overgeneralize."

  10. #10
    Senior Member
    Join Date
    May 2008
    Location
    NORCAL
    Posts
    102
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    interesting info here! well uh hopefully the rocky trails i go on wont be too much of a prob for my '02 hardrock....
    Last edited by kaitanium; 05-14-09 at 06:21 PM.

  11. #11
    Senior Member
    Join Date
    Dec 2008
    Location
    Under the Downunder
    My Bikes
    MTBs, BMX, Pocket MTB
    Posts
    1,014
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Here's a very famous headtube failure vid... ouch!

    http://www.youtube.com/watch?v=JLRDRzMWIsg
    Quote Originally Posted by dminor View Post
    Like clever mice, if there is a any crevice to exploit, a chain will find room to jump and derail; you can count on it.

  12. #12
    ****** (can I say this?)
    Join Date
    Jun 2008
    Location
    CO
    Posts
    1,900
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Svr View Post
    If you "case" a jump by landing wrong, like the rider in the video, while riding a frame never designed to survive that type of landing, failure of the frame is almost guaranteed.
    I've cased so many DJs its not even funny. And my XC frame still hasnt broken.
    “Speed has never killed anyone, suddenly becoming stationary... that’s what gets you.”- Jeremy Clarkson

  13. #13
    Senior Member
    Join Date
    May 2008
    Location
    NORCAL
    Posts
    102
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Pocko View Post
    Here's a very famous headtube failure vid... ouch!

    http://www.youtube.com/watch?v=JLRDRzMWIsg

    yea i saw that one...and that wasnt even junmping rocks and such!!! just broke...i wonder how long he has used that bike and how much abuse it has gone through

  14. #14
    gbg
    gbg is offline
    Senior Member
    Join Date
    Jan 2009
    Posts
    628
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by kaitanium View Post
    so for you trail riders out there what are the chances of a frame snapping where the steerer inserts into the frame? like this:
    http://www.youtube.com/watch?v=6UmaZ...layer_embedded

    ive seen way too many videos of this stuff. but its not like i hop rocks or anything. tons of vids like this!
    If you case it like he did, about 1 in 3.

  15. #15
    Is that the MEEWN?! greenpeppers's Avatar
    Join Date
    Apr 2009
    Location
    T.O.
    My Bikes
    Kahuna 09
    Posts
    43
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    HAHAHAHA!!!!Thanks for the vid. Finding all those fail videos were hilarious!!!!

  16. #16
    Senior Member
    Join Date
    Dec 2008
    Location
    Under the Downunder
    My Bikes
    MTBs, BMX, Pocket MTB
    Posts
    1,014
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by kaitanium View Post
    yea i saw that one...and that wasnt even junmping rocks and such!!! just broke...i wonder how long he has used that bike and how much abuse it has gone through
    This is why I am not a fan of dark colored frames (although I still have one, black ). Right now have a silver, two butter-yellow bikes, and one clear-coated bike (natural aluminum finish).

    A light colored frame will give plenty of visual warning if a crack appears, but it's difficult to catch those on dark colored frames. Having said that, I suppose it is possible to ride a bike to breaking-point without premature cracks showing...

    Over the years I've seen cracks appear in various places but the most common place I've seen them is near the welds at the bottom of the headtube/downtube connection or somewhere along it's gusset if it has one. It pays to occasionally inspect that area, especially after a crash (or if the bike crashes regularly ).

    .
    Quote Originally Posted by dminor View Post
    Like clever mice, if there is a any crevice to exploit, a chain will find room to jump and derail; you can count on it.

  17. #17
    use your best eye kenhill3's Avatar
    Join Date
    Mar 2006
    Location
    Olympia, Washington
    My Bikes
    '75 Bertin, '93 Parkpre Team 925, '04 Kona King Kikapu, '05 Bianchi Vigorelli
    Posts
    3,054
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Pocko View Post
    It pays to occasionally inspect that area, especially after a crash (or if the bike crashes regularly ).
    +1. That's why a thorough cleaning of every part of the bike on a regular basis is a sound idea. It will give you a chance to spot any defects.
    "I tell you, We are here on earth to fart around, and don't let anybody tell you any different." - Kurt Vonnegut jr.

  18. #18
    Senior Member
    Join Date
    May 2008
    Location
    NORCAL
    Posts
    102
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    mmm yes. inspection and cleaning! sometimes i dont want to clean my bike though...i love all that grime and dirt and mudsplash marks on it...

  19. #19
    use your best eye kenhill3's Avatar
    Join Date
    Mar 2006
    Location
    Olympia, Washington
    My Bikes
    '75 Bertin, '93 Parkpre Team 925, '04 Kona King Kikapu, '05 Bianchi Vigorelli
    Posts
    3,054
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by kaitanium View Post
    mmm yes. inspection and cleaning! sometimes i dont want to clean my bike though...i love all that grime and dirt and mudsplash marks on it...
    Some folks think that dirt on the bike is a badge of legitimacy.

    Yeah, a lot of times I'm just too lazy to clean the silly thing.
    "I tell you, We are here on earth to fart around, and don't let anybody tell you any different." - Kurt Vonnegut jr.

  20. #20
    Senior Member
    Join Date
    May 2008
    Location
    NORCAL
    Posts
    102
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by kenhill3 View Post
    Some folks think that dirt on the bike is a badge of legitimacy.
    hehe i do think that way sometimes but well i have nothing to hide. its not like my bike is a crazy XC or anything and im just posing like i know what im doing haha. im sure some buy some crazy looking bike, only to bike through rain puddles
    Last edited by kaitanium; 05-15-09 at 12:53 PM.

  21. #21
    ed
    ed is offline
    . ed's Avatar
    Join Date
    Oct 2005
    Location
    The Summit of Lee
    My Bikes
    Hecklah
    Posts
    10,932
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by dminor View Post
    People come on here all the time and make ill- or half-informed blanket statements...
    This seems like a blanket statement to me...I'm a typical person...all that I say is from the utmost + dedicated + research from credible sources



    Quote Originally Posted by dminor View Post
    I just decided I'm tired of seeing this stuff get thrown out here unchallenged.
    I'm a little sick of getting called out on my uninformed blanket statements. I thought that when I became deputy...I could do whatevah I dang well pleased.




    Quote Originally Posted by dminor View Post
    I'm just making a case for a little accuracy.
    I'm just making a case for a little neener, neener
    Last edited by ed; 05-15-09 at 01:42 PM.

  22. #22
    In search of moar cowbell dminor's Avatar
    Join Date
    Oct 2004
    Location
    The 509
    My Bikes
    1971 Suzuki TS125/ factory race kit/AHRMA-legal; 1969 Suzuki TS250/factory race kit; 1967 Suzuki K-15 Hillbilly Trail 80; 1977 Yamaha IT175; 1964 VanTech Scrambler racing frame
    Posts
    12,139
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by chelboed View Post


    I still remember this quote from Michael on The Office:

    "Wikipedia is the best thing ever. Anyone in the world can write anything they want about any subject. So you know you are getting the best possible information."

  23. #23
    ed
    ed is offline
    . ed's Avatar
    Join Date
    Oct 2005
    Location
    The Summit of Lee
    My Bikes
    Hecklah
    Posts
    10,932
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)

  24. #24
    Svr
    Svr is offline
    Senior Member Svr's Avatar
    Join Date
    Dec 2005
    Location
    Atlanta, GA
    Posts
    1,223
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

  25. #25
    Svr
    Svr is offline
    Senior Member Svr's Avatar
    Join Date
    Dec 2005
    Location
    Atlanta, GA
    Posts
    1,223
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

Page 1 of 2 12 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •