Hollowtech BB installation questions

Avoneer
Avoneer Posts: 525
edited May 2010 in Workshop
Hi All,

Being new to these fancy external balls, I have inserted and tightened the cups and am ready to insert my crank.

Should there be a washer or anything that slips onto the cranks 1st, or is it just a case of slide it on as it is then tap it with a rubber mallet to check it's all the way in (see pic).

If that's right, I pressume you then insert the opposite crank onto the spines, nip up the plastic retaining nut thing then tighten up the allen bolts on the crank.

Is the bearing supposed to feel slightly "tight & slightly stiff" compared to the old internal BB's that span round freely when you put the cranks on (without a chain).

Thanks,

Pat...

BB.jpg
"Campagnolo has soul, Shimano has ruthless efficiency and SRAM has yet to acquire mystique. Differentiating between them is a matter of taste"

Comments

  • topdude
    topdude Posts: 1,557
    No washers, just the thin "O" rings each side of the cups, looks like one is already on the axle in your picture.
    Yes, slide it in and nip up the nut finger tight to eliminate play, tighten bolts to correct torque. If doing without a TQ wrench then they need to be very tight.
    Yes, the bearings feel stiff to turn because the seals are very good but not a problem when actually pedalling :D
    He is not the messiah, he is a very naughty boy !!
  • Avoneer
    Avoneer Posts: 525
    Cheers topdude - answers all my q's.

    Yep - have a torque wrench so all is well.

    Pat...
    "Campagnolo has soul, Shimano has ruthless efficiency and SRAM has yet to acquire mystique. Differentiating between them is a matter of taste"
  • maddog 2
    maddog 2 Posts: 8,114
    Shimano pinch bolts are 12-15 Nm which isn't "very tight" in my book.

    Tighten one a bit, then the other, then the other...... and so on up to 12Nm.
    Facts are meaningless, you can use facts to prove anything that's remotely true! - Homer
  • Avoneer
    Avoneer Posts: 525
    Okey dokey.

    12Nm is when my elbow clicks ;-)

    Pat...
    "Campagnolo has soul, Shimano has ruthless efficiency and SRAM has yet to acquire mystique. Differentiating between them is a matter of taste"
  • Avoneer
    Avoneer Posts: 525
    All done.

    Not so sure about the chainline though.

    Only about 2mm between chainset and chainstay and large ring is parallel to my 4th sprocket on the casette - or is this ideal as that is where I tend to have my chain the most.

    Pat...

    chainline%20(Small).jpg
    "Campagnolo has soul, Shimano has ruthless efficiency and SRAM has yet to acquire mystique. Differentiating between them is a matter of taste"
  • The Spiderman
    The Spiderman Posts: 5,625
    What width bb shell?If its 68mm you should have 2 spacer on the drive side cup,1 on the non drive side.73mm 1 on drive side only.

    Be aware when tensioning the preload cap,its much like a headset in that it only needs nipped up,to eliminate play,and no tighter.
    2006 Giant XTC
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  • Avoneer
    Avoneer Posts: 525
    I didn't get any spacers - didn't think I needed any ???

    The splined end of the axle is a shade short of flush with the outer face of the "passenger side" crank arm so any spacers of any form would pull the splines further into the BB and leave less spline length for the crank arm - not sure the plastic nut would be able to take any more than about another 3mm.

    Are there different length axles when you buy your chainset?

    Pat...
    "Campagnolo has soul, Shimano has ruthless efficiency and SRAM has yet to acquire mystique. Differentiating between them is a matter of taste"
  • maddog 2
    maddog 2 Posts: 8,114
    it's only MTB chainsets that need spacers.

    The ring/chainstay clearance is okay - you just have wide stays, that's all.
    Facts are meaningless, you can use facts to prove anything that's remotely true! - Homer
  • Avoneer
    Avoneer Posts: 525
    That would make sense as it a cyclocross frame.

    Is the chainline more or less fixed then on road bikes that use hollowtech then (pressumiong all hollowtech axles are the same length) ?

    Pat...
    "Campagnolo has soul, Shimano has ruthless efficiency and SRAM has yet to acquire mystique. Differentiating between them is a matter of taste"
  • whyamihere
    whyamihere Posts: 7,708
    Avoneer wrote:
    That would make sense as it a cyclocross frame.

    Is the chainline more or less fixed then on road bikes that use hollowtech then (pressumiong all hollowtech axles are the same length) ?

    Pat...
    Yep. Mountain bike cranks can be bought with different length axles because some frames have very wide rear hubs, requiring the chainrings to be further out. All modern road bikes have the same width rear hub, putting the cassette in the same place, so they all run the same chainline.
  • PK1
    PK1 Posts: 193
    you can get spacers, my triple sora has a 6.5 mm spacer on the drive side and a 3mm one on the other, but that may make the central spindle too short for your frame for a sora double.
  • John.T
    John.T Posts: 3,698
    Sora triple does use spacers. Double does not. These go on the axle. The MTB ones fit behind the cups.