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  1. #1
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    Torque specs - Avid BB7s

    I just ordered some BB7s for my ride (switching from v-brakes!), and I've scanned through the online SRAM manuals and watched the youtube vids of the install. The procedures look extremely easy, so that's cool. This will be my first major part swap besides pedals and tires, and I don't have a torque wrench. Is it absolutely necessary to have one? How many of you do your builds without one? When installing my pedals I just tightened them to what I thought was tight, but not strip-the-threads tight, and I have had zero problems.

    If I absolutely must have a torque wrench, is there a cheap one out there worth having?

    Thanks in advance fellow dirt flingers!

  2. #2
    offroader
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    You don't need a torque wrench. If you ordered retail BB7 in box then they should come with a torx wrench.

  3. #3
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    The torx wrench is just a hex driver, right? I have those. I'm asking if anyone has installed these brakes without actually using a torque wrench. For example, the rotor should be torqued to 80-90 in/lbs per the instructions. I have no way of measuring that without a torque wrench. I want to know, ultimately, if there is anything I should watch out for. I plan to tighten everything down as tight as I can without stripping anything out or warping a rotor, for example. Just looking for advice...

  4. #4
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    Unless Avid has recently changed the rotor bolts, they are T-25 torx bolts and are torqued to a value of 55 in-lbs (I do seem to remember there's some misprint in the instructions recently, though). 80-90 in-lbs is the value for the caliper mounting bolts. I do use a torque wrench personally; a beam type 1/4" drive would probably be best for that torque range price wise. Don't know anyone who can loan you the tools? You could probably get away without using one if you apply torque judiciously...
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  5. #5
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    the new torque specs for the rotors are now 80-90

  6. #6
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    Quote Originally Posted by Freewillie
    The torx wrench is just a hex driver, right?
    Different shape. Looks like this picture. Like COJ said, there should be one in the retail box
    Attached Images Attached Images

  7. #7
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    Quote Originally Posted by doco
    the new torque specs for the rotors are now 80-90

    I've wondered if they just increased them by 50 plus percent or did they change something? I'm thinking it's still a misprint. Do they still print the torque value on the rotors? All my Avid rotors have 55 in-lbs printed on them....and the Juicy manual still shows 55 in-lbs.
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  8. #8
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    yeah my rotor have the old 6.2nm spec, but the manual that came with the set says 80-90

    I forgot where on this forum, but I found out about it when someone posted that they had tightened to the 6.2 spec and was having problems...they then went to the online Sram site for the tech documents and the new torque was the 80-90

    he tightened them up and the problem vanished

  9. #9
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    Quote Originally Posted by doco
    yeah my rotor have the old 6.2nm spec, but the manual that came with the set says 80-90

    I forgot where on this forum, but I found out about it when someone posted that they had tightened to the 6.2 spec and was having problems...they then went to the online Sram site for the tech documents and the new torque was the 80-90

    he tightened them up and the problem vanished
    I've been using the 6.2Nm spec (55 in-lbs) for more than 8 years on several sets of BBDB/BB7s with no problems as have many others. YMMV. Funny how the hydraulic brake manual still has the 6.2Nm spec....

    What was the problem this other person had?
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  10. #10
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    The torque spec for the rotor...

    bolts is 55 lb/in and is etched right on the outside of the rotor near the bolt holes. This applies to the roudagon, cleansweep, and cleansweep 2 rotors. I can't speak for the CS 3s, haven't seen a set yet.

    As for the original question, Yes I use a torque wrench when installing brakes, and high torque or very low torque items on a bike build. The reason being, high torque items like cranks and bottom brackets are too easy to get too low by hand. Low torque items are too easy to over torque and strip out. And brakes are CRITICAL. And torque spec is esspecially important with the CPS washer system that Avid uses. To tight and the washers take a set and won't adjust correctly afterward, too loose and the caliper will tend to move on it's own. Just right an you have no problems.

    Anyway, I'd highly recommend a torque wrench for your brake setup as a minimum. There are many other useful places that it can be used on the bike as well.

    Oh, and you will need a T-25 Torx bit for the rotor bolts. You should be ablel to find one for a 1/4 or 3/8 drive wrench no problem.

    Good Dirt
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  11. #11
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    Quote Originally Posted by Squash
    As for the original question, Yes I use a torque wrench when installing brakes, and high torque or very low torque items on a bike build. The reason being, high torque items like cranks and bottom brackets are too easy to get too low by hand. Low torque items are too easy to over torque and strip out. And brakes are CRITICAL. And torque spec is esspecially important with the CPS washer system that Avid uses. To tight and the washers take a set and won't adjust correctly afterward, too loose and the caliper will tend to move on it's own. Just right an you have no problems.

    Anyway, I'd highly recommend a torque wrench for your brake setup as a minimum. There are many other useful places that it can be used on the bike as well.

    Oh, and you will need a T-25 Torx bit for the rotor bolts. You should be ablel to find one for a 1/4 or 3/8 drive wrench no problem.

    Good Dirt
    Thanks Squash. I gave up hope that anyone was actually going to answer my original question. Somehow my post turned into a debate about the actual torque specs, not whether a torque wrench was actually necessary. I can see the need with the CPS washers, though. That makes sense.

  12. #12
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    Quote Originally Posted by Freewillie
    Thanks Squash. I gave up hope that anyone was actually going to answer my original question. Somehow my post turned into a debate about the actual torque specs, not whether a torque wrench was actually necessary. I can see the need with the CPS washers, though. That makes sense.
    Well I did give you my .02 about the torque wrench, that's what lead into sidetracking your thread, sorry...
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  13. #13
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    What was the problem this other person had?[/QUOTE]


    here is the thread, scroll down to JoeJack....something about vibration problems

    http://www.bikeforums.net/showthread.php?t=506698
    BB7 Install trouble - Bike Forums

  14. #14
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    Quote Originally Posted by doco
    What was the problem this other person had?

    here is the thread, scroll down to JoeJack....something about vibration problems

    http://www.bikeforums.net/showthread.php?t=506698
    BB7 Install trouble - Bike Forums[/QUOTE]

    Yeah, that was where I first heard of the misprint...
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