Bottom bracket spindle length question

ricktabor1
ricktabor1 Posts: 272
edited June 2011 in Workshop
I've got a problem with a Trek Pilot 1.2 (2006).

The BB needs replacing and i'm not sure what spindle length I need. I've ordered a new BB removal tool which hasn't arrived yet so I can just look at the one that needs replacing.

The bike has a 68mm shell and a Bontrager Select triple chainset.

Does anyone know what size i need? Also how do I find this kind of info? Shimano is good for the tech docs but I can't find info on other makes.

Thanks
Got to get up to get down

Comments

  • alfablue
    alfablue Posts: 8,497
    edited June 2011
    You can measure the length of the existing spindle (D) (assuming the cranks are off)

    spindle.jpg

    It is possible that the ends are not symetrical, but if they are equal length then its simply 68 x D for your BB size (such as 68 x 113 for example).

    See http://www.sheldonbrown.com/bbsize.html
  • anyuser
    anyuser Posts: 51
    Have a look here:
    http://www.sheldonbrown.com/bbsize.html
    Sheldon lists 113mm for all Bontrager square taper versions and 118 for the ISIS triple.
    Personally I would wait and get the old one out and measure just to be sure.
  • alfablue
    alfablue Posts: 8,497
    Shimano UN54 for £15 here: http://www.ukbikestore.co.uk/product/16 ... taper.html

    Pretty good price, this BB should last for years.
  • keef66
    keef66 Posts: 13,123
    Some sizes of UN54 are even cheaper at CRC. (Unfortunately not the size I needed though!) and they have the UN26 in 3 sizes for £9.99.
  • maddog 2
    maddog 2 Posts: 8,114
    ebay has loads of UN54 sizes too

    and a few of the much lighter UN71/72/73
    Facts are meaningless, you can use facts to prove anything that's remotely true! - Homer
  • ricktabor1
    ricktabor1 Posts: 272
    Thanks for the advice guys.

    I forgot to say, the BB is splined (ISIS).

    I'll have a go at measuring it whilst in the shell. See if it agrees with old Sheldon Brown's listing.
    Got to get up to get down
  • nicklouse
    nicklouse Posts: 50,675
    ricktabor1 wrote:
    Thanks for the advice guys.

    I forgot to say, the BB is splined (ISIS).

    I'll have a go at measuring it whilst in the shell. See if it agrees with old Sheldon Brown's listing.

    it will be one of 3 length and most likely be 118mm for a tripple
    see
    http://www.bikeradar.com/forum/viewtopic.php?t=12737715
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown

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