How many spacers??

shropshirelad1
shropshirelad1 Posts: 22
edited February 2013 in MTB workshop & tech
Hi all, just starting my genesis core build and have a question.
I'm using an SLX double crank with a hollow tech BB, but I'm unsure how many spacers I need to fit.
The bottom bracket on the bike measures 68 mm.
Any ideas?
Cheers

Comments

  • nicklouse
    nicklouse Posts: 50,675
    TBH it is in the manual. it is on parktools.

    if you are not fitting anything else you need 3. 2 drive-side and one Non Drive-side.

    you have had the Shell faced haven't you.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • shropshirelad1
    shropshirelad1 Posts: 22
    Thanks, I'll take a look on the park tools site.
    No I haven't had the BB faced as its a brand new frame looks ok to me
    Should I be getting it faced??
    Cheers
  • shropshirelad1
    shropshirelad1 Posts: 22
    Just looked on park tools site and your right, 2x spacers on the drive side and 1x spacer on the non-drive side.
    Nice and easy
    Thanks
  • The Rookie
    The Rookie Posts: 27,812
    shropshirelad1 wrote:
    Should I be getting it faced??
    Yes, the shell needs facing for external BB's, if it's not been faced (and you can confirm it has) it needs doing, regardless of age.
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • shropshirelad1
    shropshirelad1 Posts: 22
    This facing lark seems quite important, you'd think that most frames would be done by the manufacturers, I'll measure with a vernier to ensure its all square, just need to borrow one first :D
  • nicklouse
    nicklouse Posts: 50,675
    you never know.

    had a 2K frame in that you would have thought would be good.

    1mm off.

    and using a Vernier is pointless.

    get the cutter on it to see.

    see the topic in the FAQs for more info.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • shropshirelad1
    shropshirelad1 Posts: 22
    Will take a look thanks, but think I'll still get the verniers on it, that way I can be sure it's all square across the width of the BB.
  • shropshirelad1
    shropshirelad1 Posts: 22
    nicklouse wrote:
    you never know.

    had a 2K frame in that you would have thought would be good.

    1mm off.

    and using a Vernier is pointless.

    get the cutter on it to see.

    see the topic in the FAQs for more info.

    Just read about chasing the threads and facing the BB in the FAQ's - great info !! that tool looks expensive, might have to take it to my local bike shop. Need to find out what tolerances are allowed to see if its necessary .
  • nicklouse
    nicklouse Posts: 50,675
    if it has not been done get it done or you will be replacing bearings more often than you should be.
    about 600 quid. and the only way to tell is to get the cutter on it.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • shropshirelad1
    shropshirelad1 Posts: 22
    Well finally got round to measuring my BB and found only 0.01mm max difference accross the width so doesn't need facing. All fitted now :)
    Pressed in my new Hope headset too using a homemade tool - a bit of allthread and some off cuts of acetal from the toolroom at work. It worked a treat..
  • nicklouse
    nicklouse Posts: 50,675
    shropshirelad1 wrote:
    Well finally got round to measuring my BB and found only 0.01mm max difference accross the width so doesn't need facing. All fitted now :)
    Pressed in my new Hope headset too using a homemade tool - a bit of allthread and some off cuts of acetal from the toolroom at work. It worked a treat..
    eeee

    hell it could have no difference and still need facing.

    it is not a length measurement you have totally missed the point of it.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • The Rookie
    The Rookie Posts: 27,812
    The two faces could be parallel and still not square to the shell, as Nick says, you completely miss what the point of facing is.
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • shropshirelad1
    shropshirelad1 Posts: 22
    I understand the principle behind facing but its not needed here. Facing ensures the face of the shell is square to the thread.
    I'm confident that it will be fine :-)
  • The Rookie
    The Rookie Posts: 27,812
    May be, may not be, you haven't checked it though.....
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.

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