Advertise on Bikeforums.net



User Tag List

Results 1 to 14 of 14

Thread: Over torqued

  1. #1
    Senior Member Plainsman's Avatar
    Join Date
    Jan 2005
    Posts
    959
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Over torqued

    So I was installing a set of Oval Concept Slam aero bars and did not have the instructions. I looked up the torques in Leonard Zinns book. I wound up stripping the threads out of the clamp brackets and had to order new ones, as I over torqued the bolts. Later found out Oval said 6nm, Zinn said 8nm, I read the wrong line and went closer to 10. Lesson learned...

    Anyway, I also overtorqued the armrest bolts, by almost double it appears, but the bolts didn't strip or shear off. I've since backed them off to the right torque (4nm). Question is, is there any danger using something that has been that overtorqued?
    Life IS an endurance sport. Finish Well.
    Finish Well Endurance

  2. #2
    AEO
    AEO is offline
    Senior Member AEO's Avatar
    Join Date
    Jun 2007
    Location
    A Coffin Called Earth. or Toronto, ON
    My Bikes
    Bianchi, Miyata, Dahon, Rossin
    Posts
    12,245
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    check for cracks or crush ripples.
    if you don't see any, it's probably fine since the thing might have been over constructed compared to the manual.
    Food for thought: if you aren't dead by 2050, you and your entire family will be within a few years from starvation. Now that is a cruel gift to leave for your offspring. ;)
    http://sanfrancisco.ibtimes.com/arti...ger-photos.htm

  3. #3
    Senior Member z415's Avatar
    Join Date
    Apr 2006
    Location
    Gainesville/Tampa, FL
    My Bikes
    Trek 1000, two mtbs and working on a fixie for commuting.
    Posts
    2,347
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I'm sure you would feel something give if you seriously damaged something so I wouldn't worry, though I would check.
    Falling is learning...[SIGPIC][/SIGPIC]...learn to not fall in a box.
    Any good American will watch THIS -and- WHERE WAS MY BIKE MADE?

  4. #4
    Great State of Varmint Panthers007's Avatar
    Join Date
    Sep 2008
    Location
    Dante's Third Ring
    Posts
    7,481
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    I would imagine that the weakest part of your bars would be the threads on the bolts and the threads of where they go. So I'd carefully examine those first. If you are absolutely certain they are fine, you are most likely good to go. But check everything closely first. Got a magnifying-glass?
    How do you keep an idiot in suspense?

  5. #5
    Member
    Join Date
    Dec 2008
    Posts
    40
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    You've probably over stretched the bolts.

  6. #6
    Senior Member DanteB's Avatar
    Join Date
    Sep 2006
    Location
    Bakersfield, Host of the 2012 ToC ITT
    My Bikes
    Waterford 2200
    Posts
    1,747
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Plainsman View Post
    So I was installing a set of Oval Concept Slam aero bars and did not have the instructions. I looked up the torques in Leonard Zinns book. I wound up stripping the threads out of the clamp brackets and had to order new ones, as I over torqued the bolts. Later found out Oval said 6nm, Zinn said 8nm, I read the wrong line and went closer to 10. Lesson learned...

    Anyway, I also overtorqued the armrest bolts, by almost double it appears, but the bolts didn't strip or shear off. I've since backed them off to the right torque (4nm). Question is, is there any danger using something that has been that overtorqued?
    I've always stressed using a torque wrench. With the new metals and carbon fiber to me it is important to use a torque wrench.
    Make mine a double!

  7. #7
    Great State of Varmint Panthers007's Avatar
    Join Date
    Sep 2008
    Location
    Dante's Third Ring
    Posts
    7,481
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Too often I find my beam torque-wrench will require Yoga to read on a great many bolts. They demand I flip the tool over so the meniscus is upside-down. If someone would develop a cheap T-W with a rotating meniscus, I'd use one all the time (almost).
    How do you keep an idiot in suspense?

  8. #8
    Senior Member DannoXYZ's Avatar
    Join Date
    Jul 2005
    Location
    Saratoga, CA
    Posts
    11,495
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Hmmm... something doesn't add up... Torque of 6-Nm would NOT stretch or strip a 5mm bolt, no way! And I bet those aero-bar bolts are probably 6mm. My guess is the threads were already messed up from numerous previous uses and this last overtightening stripped them.

    Now that you've got new part, get a torque-wrench and you'd be set. Also be aware that torque-specs are given assuming machine-oil on the threads. Otherwise, friction on the threads would give added resistance and appear to be tight, but the bolt hasn't been stretched enough to give adequate clamping force.

  9. #9
    Senior Member
    Join Date
    Sep 2008
    Location
    Loveland, CO
    My Bikes
    Two LOOK 585s, one KG461
    Posts
    4,987
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I always stress the need for would-be bike mechanics to learn what these low torque values feel like, when applied with a short handled hex wrench or 4-5-6mm Y-style wrench. I've been wrenching on bike for over 25 years and never once found the need for a torque wrench on M5 or M6 bolts. All of my bikes have carbon frames, carbon bars and carbon seatposts.

    There is always the need to make on the road adjustments. How are you going to do it if you've got no clue about how much to tighten a stem or seatpost clamp bolt?

  10. #10
    Great State of Varmint Panthers007's Avatar
    Join Date
    Sep 2008
    Location
    Dante's Third Ring
    Posts
    7,481
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    6 Nm is approx. 53 inch pounds. So I don't see that damaging a bolt either.
    How do you keep an idiot in suspense?

  11. #11
    Senior Member Plainsman's Avatar
    Join Date
    Jan 2005
    Posts
    959
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    The issue was I blew past 6 to 10, a double miss, Oval concepts says the torque is 6 but I didn't have their instructions so I went by the chart in Zinn's book that said 8. Unfortunately, I read the wrong line in the Zinn book and went to 10, yikes! Turns out I did strip them. Replacement parts on the way. Lessons learned... Thanks all!
    Life IS an endurance sport. Finish Well.
    Finish Well Endurance

  12. #12
    Guest
    Join Date
    Jul 2008
    Location
    Grid Reference, SK
    My Bikes
    I never learned to ride a bike. It is my deepest shame.
    Posts
    3,769
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    It does seem like a pretty small torque, though.

  13. #13
    Great State of Varmint Panthers007's Avatar
    Join Date
    Sep 2008
    Location
    Dante's Third Ring
    Posts
    7,481
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    More and more components are coming that have explicit torque settings in the instructions. Due to the OP's experience - and many, many others - with stripping bolts, I have come to highly recommend that even the experienced bike-mechanics out there invest in torque-wrenches. The Park Tools TW-1 & TW-2 are relatively inexpensive, and quite accurate. Cheaper than the aggravation of stripping the threads out of a brand-new derailleur or a Thomson stem.
    How do you keep an idiot in suspense?

  14. #14
    Senior Member
    Join Date
    Aug 2005
    Location
    Pittsburgh, PA
    My Bikes
    '''96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '12 Surly Pacer, All are 3x8,9 or 10. It is hilly around here!
    Posts
    25,646
    Mentioned
    6 Post(s)
    Tagged
    0 Thread(s)
    I wouldn't be as concerned about the clamp bolts as I would about the handlebars. If the clamps were greatly overtorqued and the base bar is Carbon, that's where the damage is more likely and more dangerous.

Posting Permissions

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