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  1. #1
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    External BB torque

    How do you torque the BB cups for an external system using the Park BB tool?

  2. #2
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    Reputation: Bikinfoolferlife's Avatar
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    I was on the road so had a shop install my first external type crankset recently, and provide me with a tool. When I asked that question they said until the tool leaves a clear impression on your hand (it's a relatively short metal handle and would definitely leave a nice impression) but actually suggested that I put a handlebar grip over the end and tighten it as much as I could with that wrench. They did not have the ability to use a torque wrench either...I'm not sure I've seen a torque figure but internal bb cups require a fair amount so suspect so would the external type (which was about right when I looked just now at parktool, sez 305-435 in/lb).
    "...the people get the government they deserve..."
    suum quique

  3. #3
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    That is kind of what I thought. It must be a "feel" thing to get close to the suggested torque values. Thanks.

  4. #4
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    Don't worry about stripping the threads. If you have forarms strong enough to strip a bottom bracket with a BBt7, you should be tearing phone books in half, not biking. As far as fear of the cups backing out? If that becomes a problem, use a little lock tight or put a pipe on the end of your wrench and use the extra leverage.

  5. #5
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    You can't

    but you can if you buy an BB that fits in a torque wrench. I have one from Cyclus for Shimano external BBs that fits a 3/8'' torque wrench. I used to think that I could "feel" how much I torqued using the Shimano tool (should be 35-50Nm) but when I checked the torque with the Cyclus tool and a torque wrench I found out I had torqued the BB cups at around 80Nm. Fortunatelly there was no damage in the frame or the cups but this should give you an idea how wrong you can be. Bear in mind that originally I had tightened the cups with the shimano tool bare handed (and yes it did leave a mark on my palm).

  6. #6
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    I tighted my RF external cups using the shimano tool too, no torque wrench. For my install, I needed two spacers one side, and one spacer on the other side. For the one spacer side, I tighted the cups so much, that it smashed the spacer and ripped it in half! I'm not sure if I screwed something up but I ended up replacing the spacer with a metal cassette spacer. I have no clue what shimano cranks come with, but RF cranks have a hard rubbery spacer for the bearing cups. Just a thought. I know I can't rip telephone books in half, I tried. The spacer might have been defective or something.

  7. #7
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    Quote Originally Posted by be350ka
    How do you torque the BB cups for an external system using the Park BB tool?
    The Park Tool site says:
    Tighten fully, approximately 305 to 435 inch pounds. When using the BBT-9, and grabbing the tool about 6-inches (15 cm) from the cup, apply about 60 pounds of effort (27 kilograms) of effort to tighten the cups.
    If you can arrange for your bike and stand together to weigh about sixty pounds, then you know you've torqued it enough when you're able to lift the bike plus stand off the floor with the wrench handle parallel to the floor.

    It is possible to overtorque these cups. I overdid it with one of my cups and started to strip the threads on the bearing cup. Fortunately, the frame threads all still look okay. It'd be nice if someone were to make a tool to which a proper torque wrench could be fastened. I don't trust myself to get it right by feel.

  8. #8
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    There is a tool

    Quote Originally Posted by KevinB
    It'd be nice if someone were to make a tool to which a proper torque wrench could be fastened. I don't trust myself to get it right by feel.
    As I mentioned in my previous post Cyclus already has a tool that fits a 3/8'' torque wrench.
    You can download their catalog at:
    http://www.framebuilding.com/cyclus%20tools.htm

  9. #9
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    Quote Originally Posted by GreekBiker
    As I mentioned in my previous post Cyclus already has a tool that fits a 3/8'' torque wrench.
    You can download their catalog at:
    http://www.framebuilding.com/cyclus%20tools.htm
    I misunderstood your earlier post. My apologies...

    Do you know of a North American distributor who carries this tool?

  10. #10
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    Exact torque on outboard cups is not quite as important anymore as in other standards. The spindle and cranks arms are completely independent so they sort of lock them in place. When they bottom out just give them a good nudge so they stay in place. Just use common sense and don't overdo it.

  11. #11
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    No need for apologies,

    Quote Originally Posted by KevinB
    I misunderstood your earlier post. My apologies...

    Do you know of a North American distributor who carries this tool?
    I live in Europe so unfortunately I don't know of a North American distributor but you could do a web search and if you still can't find one you can always order from Europe.

  12. #12
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    Thanks guys! I sent an email to see where I can pick up one of those tools.

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