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  1. #1
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    Bushings maintenance - Torque wrench really necessary?

    Reading Turner's bushings maintenance it specifies to tighten the main pivot Torx screws to 17 ft/lb and the others to 9 ft/lb.

    Since I will have to buy a new torque wrench to do this (mine is an automotive application one starting at 25 ft/lb) and these things ain't cheap - do I really need one at all or can I just 'nip' the Torx screws snug and make sure I use blue Loctite?

    What do Homers do?

  2. #2
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    Most folks run to Sears and get a $25 Torque wrench. It's worth it for many things on the bike. In the long run you'll have a better dialed ride and less odd/unusual problems that come from uneven/under/over torquing.

    Then there's the peace of mind value.

    It's a $3500 bike, splurge on the right tools.
    Faster is better, even when it's not.

  3. #3
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    +2 on the torque wrench. I've got two, one big one that is 10-250 ft_lbs and one that measures in_lbs/n*m

    There are a myriad of uses like Thomson face plates, Avid CPS bolts, post mount brakes, crank arms....

    Well worth the investment on a prized posession like a Turner.
    Happiness depends more on the inward disposition of mind than on outward circumstances. Benjamin Franklin

  4. #4
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    Call me Crazy!!

    But, I didn't use a torque wrench. If I was going to buy one, I'd buy the Park beam style, because unlike the click type:
    -it is never inacurate. The click type need to be calibrated after being improperly stored with the spring tension set above zero, or if it is dropped.
    -I find the Park beam type actually have a 'FEEL' that is lacking on the other type.

    Cheers,

    Kane

  5. #5
    TLL
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    I used to wrench on cars (and bikes) for a living and had several Snap-On torque wrenches. Yeah, you are supposed to zero out a torque wrench before you store it, and realistically you should have them re-calibrated every year. But to be honest, for most bike applications, close enough is good enough--most torque values are given as a range anyway. Not all, mind you--just most. so there is a built in fudge factor that you can take into account, assuming your wrench is not 100% accurate. If you want to be 99.9% exact, by all means use a beam wrench. No wrench is 100%.

    Having said that, I did a little research (I asked my buddies what they used) and found the following wrench to do a very decent job; it is the Performance wrench, 3/8 drive, 25-250 inch/lb. wrench.:

    http://www.mytoolstore.com/wilmar/prod043.html (first wrench on page)

    This would be the bare minimum for a wrench, as far as I an concerned. the SK torque wrenches are nicer and more accurate, but they are closer to $80. Syntace, Snap-On, and Mac all make exceptional wrenches as well, but expect so spend $200 or more. And the Park beam wrench is pretty nice, really. But do yourself a favor, do not buy a $20 special off Fleabay--total waste of money.

  6. #6
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    ...then there's a whole other side to consider, torque values are normally given for a 'dry' fastener, unless otherwise specified.
    I don't recall the general formulas, but if there is loctite or grease, or even the oil from your finger, anywhere on the threads, it changes (lowers?) the values.
    Once a fastener has been torqued, it stretches, and that effects any re-use. It gets complicated.
    Using a torque wrench is still a great idea, but you still have to be smart about it...
    ...every day sends future to past...

  7. #7
    TLL
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    XJ, you are correct, adding grease would lower the value somewhat. I've seen figures, but of course cannot remember what they are. somewhere in the range of 5% or so.

    As for being smart, all I can say is that years of experience (and mistakes) tend to make you smarter . . . .

    Like the time I was rebuilding a 356 motor and left off some cooling shrouds . . . I only did that once . . . and my boss just laughed at me.

  8. #8
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    Quote Originally Posted by Digger90
    Bushings maintenance - Torque wrench really necessary?
    No, not necessary. Just like a headset press isn't necessary.

    Quote Originally Posted by Digger90
    What do Homers do?
    Homers will obsess about torque values, the best color for a torque wrench and post many horribly exposed, horribly composed pictures of their torque wrenches that rarely see use (there's an analogy in there somewhere).

    This obsessing will encompass many posts in many threads (that analogy thing again).

  9. #9
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    I bought a torque wrench to use on the lug bolts for my alloy car wheels, and would use one for fasteners where preload is critical (like head studs). For most fasteners there's a pretty wide range of acceptable preloads. Engineering guides will tell you around 60% of proof load is enough to prevent loosening, and 75-90% of proof load may be used in fatigue-critical applications (tighter is better). The tightening torque is calculated based on desired preload and an assumed friction coefficient. There's obviously enough range in the unknowns that 1% calibration of a torque wrench is hardly necessary.

    I never use a torque wrench on bike parts. I think most mechanics develop a feel for what's "right" and use wrenches of an appropriate length for the application. Don't reef on a small stainless screw threaded into aluminum. BB cups (easy to cross-thread!) and pedals need to be pretty tight, so grease threads and use a longer wrench. If the spec is for 17 ft-lb on a pivot screw, it's easy to figure out that that's a pretty hard pull for most people using a Torx socket and 6" ratchet handle. Carry the wrench on the first ride or two and re-check. Most clamp screws (stem onto steerer, controls on bars, f. der. clamp, s.p. clamp, cable clamps) don't need to be too tight, and crash damage will be reduced if things can move when they need to. Brake caliper mounting screws I go fairly tight on and re-check after riding. You'll learn which screws tend to loosen (like seat rail clamps) and snug up as necessary.

    Double-check anything done by a shop, unless you know for sure that whoever worked on your bike has more sense and experience than you do, and wasn't in a rush! I still get hosed when I take my car in for stuff that I don't have time or a particular tool to do myself.

  10. #10
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    I built a 327 in my driveway... pistons, rings, cranks and all... what an awesome experience... thay beyotch ran like the devil with his azz on fire.... I'd do it again in a heartbeat. Everyone should own a Vette once in their life. (and never sell it!)

    I agree experience gets you a lot of feel for how tight is right.
    I don't' think a pivot bolt is one of those places.

    Yeah, you can get away with whatever keeps it from falling off but doing it right gives you both optimal performance(minimum stiction) and wear life. It also helps prevent a bolt from unexpectedly backing out as many ppl have found happen with drive side lower main pivot bolts. It is the worst place for this to happen b/c you won't notice it right away since you don't really see it via casual observation.
    It could interfere with your chainrings if it gets out far enough. More importantly, a loose pivot will wear out much faster and cause a vague flexy ride almost immediately.

    But hey, if a thirtyfive hundy bike ain't worth an extra quarter Benny, then by all means, reef away.

    Oh and while your at it, remember to not buy pivot grease as you don't really need it either... I mean ppl get 2-3 yrs w/o doing d!ck so WTF just swap em out like bearings...without a torque wrench of course.
    Last edited by Bikezilla; 07-01-2008 at 08:31 PM.
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  11. #11
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    Quote Originally Posted by Bikezilla
    Everyone should own a Vette once in their life.
    I just threw up in my mouth. Heaven forbid that I become a Tupperware pilot at some point. It's akin to owning a "top of the line" Ibex.

    I agree experience gets you a lot of feel for how tight is right.
    I don't' think a pivot bolt is one of those places.

    Quote Originally Posted by Bikezilla
    Yeah, you can get away with whatever keeps it from falling off but doing it right gives you both optimal performance(minimum stiction) and wear life. It also helps prevent a bolt from unexpectedly backing out as many ppl have found happen with drive side lower main pivot bolts. It is the worst place for this to happen b/c you won't notice it right away since you don't really see it via casual observation.
    It could interfere with your chainrings if it gets out far enough. More importantly, a loose pivot will wear out much faster and cause a vague flexy ride almost immediately.
    I just knew that the Chicken Littles would come squawking out of the hen house.

  12. #12
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    Tupperwear pilot! I like that! Plastic hat and all!
    Faster is better, even when it's not.

  13. #13
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    dont swet it zilla. petes a porsche boy and i think theres a analogy about that too.
    No, I'm NOT back!

  14. #14
    Roy
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    Quote Originally Posted by Digger90
    do I really need one at all
    No.

  15. #15
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    Getting a torque wrench today

    I second the opinion that the lower drive-side pivot isn't a place to just tighten it "by feel" if you are an average rider/wrencher.

    Just last night, after 3 nights of taking apart my entire Highline to locate a mystery creak in the drivetrain... wasn't the bottom bracket, took that apart, packed bearings, etc, wasnt the chainrings, cleaned up those threads, not the pedal bearings or bushings, not the spindle, not even the tricky seatpost/clamp/seat. So moved on to the shock mounts, the ti spring contact points, headset (just in case).

    Just as I was about to concede and ride with a creaky bike for life, decided to triple-check all of my pivot points, got down to the drive side pivot torx, gave it an extra crank and voila! NO MORE CREAK.

    Have learned my lesson, torque settings matter and I am not just winging it anymore, my "feel" is not good enough and engineers know what the hell they are doing most of the time.

  16. #16
    Roy
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    Quote Originally Posted by NoShirt
    Just as I was about to concede and ride with a creaky bike for life, decided to triple-check all of my pivot points, got down to the drive side pivot torx, gave it an extra crank and voila! NO MORE CREAK.
    So you since you didn't re-tighten it with a torque wrench, rather you just had a second pass based on feel, you are actually strengthening the argument that a torque wrench is not needed.

  17. #17
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    I think NS' point was that it might not have backed out in the first place if it were properly torqued to begin with.

    -maybe-

    Faster is better, even when it's not.

  18. #18
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    NOPE- Fact is, it probably wasn't tight enough (hence the creak I would assume), I tightened it more, creak goes away. Creak is gone, but I still don't know if it's tight enough, or too tight (or any other bolt on my bike for that matter). I can't tell without a torque wrench, so I better use one.

  19. #19
    ... I guess you won't be
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    FYI - adding grease to a bolt/s will not increase or decrease the absolute torque setting. All the grease does is remove static friction from the equation, allowing for an easier setting of a torque value to the bolt via a torque wrench.

    And, as a special bonus tip, when reaching the requested torque value, loosen the bolt slightly, and then re-torque to the same value - that ensures that static friction has been minimized, grease or no grease.
    Yes, we do indeed rock...http://www.myspace.com/spokedrunkies

  20. #20
    Roy
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    I think that was NS' intended point, but I don't think it turned out quite as expected...

    -maybe-

  21. #21
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    To clarify, the "maybe" was directed towards the idea that a properly torqued bolt is less likely to back out... I think arguements could also be made that is not necessairly true. (I don't know for sure myself)

    My point from my first post is that having properly torqued bolts...especially pivot bolts... can help avoid mysterous problems and creaks from cropping up, and avoid excess stiction, flex or slop.

    My later point was that you can get by without a torque wrench with experience and/or sensibility, but I'd rather not do pivot bolts without one for the reasons stated above.


    YMMV
    Faster is better, even when it's not.

  22. #22
    Roy
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    I do not disagree with anything you just said. I disagree with the claim that a torque wrench is needed to properly torque a bolt/nut/shoestring/rubberband, that is all.

  23. #23
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    I'm just wondering why Turner isn't using an integrated torque wrench...
    Faster is better, even when it's not.

  24. #24
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    OK, OK - enough! :-) I've just ordered a shiny new Park beam Torque wrench and some new Torx T40 wrenches...


    Here's another related question: pivot has grease, pivot bolt has blue Loctite on threads.

    Should I put a smear of grease under the conical bolt head on the pivot bolt, to allow it to swivel? (or doens't it swivel..?)

  25. #25
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    I think as long as you follow the Turner maintenance guide, you can't go wrong.
    Happiness depends more on the inward disposition of mind than on outward circumstances. Benjamin Franklin

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