• Thinking of changing crank 165m to 175mm

    From Catrike Ryder@21:1/5 to All on Wed Feb 19 18:47:05 2025
    I found a lightly used set of 175mm crank arms capable of taking a 5
    bolt 130mm triple.

    The seller says they have a ISIS BB interface. My current crankset is
    Sram Hollowcore so I'll need a new Bottom Bracket. My current BB is a
    Sram Truvita Team GXP English. I had no trouble changing out the worn
    out OEM Sram GXP BSA 10-4, but I'm at a loss on how to select the
    correct ISIS BB.

    Any help will be appreciated.

    --
    C'est bon
    Soloman

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  • From AMuzi@21:1/5 to Catrike Ryder on Wed Feb 19 19:28:04 2025
    On 2/19/2025 5:47 PM, Catrike Ryder wrote:

    I found a lightly used set of 175mm crank arms capable of taking a 5
    bolt 130mm triple.

    The seller says they have a ISIS BB interface. My current crankset is
    Sram Hollowcore so I'll need a new Bottom Bracket. My current BB is a
    Sram Truvita Team GXP English. I had no trouble changing out the worn
    out OEM Sram GXP BSA 10-4, but I'm at a loss on how to select the
    correct ISIS BB.

    Any help will be appreciated.

    --
    C'est bon
    Soloman

    Check out the crank manufacturer's page on that product for
    recommended spindle length.

    --
    Andrew Muzi
    [email protected]
    Open every day since 1 April, 1971

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  • From Catrike Ryder@21:1/5 to AMuzi on Thu Feb 20 05:39:43 2025
    On Wed, 19 Feb 2025 19:28:04 -0600, AMuzi <[email protected]> wrote:

    On 2/19/2025 5:47 PM, Catrike Ryder wrote:

    I found a lightly used set of 175mm crank arms capable of taking a 5
    bolt 130mm triple.

    The seller says they have a ISIS BB interface. My current crankset is
    Sram Hollowcore so I'll need a new Bottom Bracket. My current BB is a
    Sram Truvita Team GXP English. I had no trouble changing out the worn
    out OEM Sram GXP BSA 10-4, but I'm at a loss on how to select the
    correct ISIS BB.

    Any help will be appreciated.

    --
    C'est bon
    Soloman

    Check out the crank manufacturer's page on that product for
    recommended spindle length.

    I couldn't find anything about a cartridge BB specifically on a
    Catrike.

    My confusion was establishing the proper overall cartridge length from
    my shell width, which is 68mm. I see 68 x 108, 68X113, 68X118. It
    seems to me that the differences will only involve the chainline,
    which shouldn't matter too much because my chainlines run through
    idlers, but still I want to minimize chain deflection. Sheldon's
    website solved the problem for me. Triples and singles use the 113s.

    --
    C'est bon
    Soloman

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  • From AMuzi@21:1/5 to Catrike Ryder on Thu Feb 20 08:20:45 2025
    On 2/20/2025 4:39 AM, Catrike Ryder wrote:
    On Wed, 19 Feb 2025 19:28:04 -0600, AMuzi <[email protected]> wrote:

    On 2/19/2025 5:47 PM, Catrike Ryder wrote:

    I found a lightly used set of 175mm crank arms capable of taking a 5
    bolt 130mm triple.

    The seller says they have a ISIS BB interface. My current crankset is
    Sram Hollowcore so I'll need a new Bottom Bracket. My current BB is a
    Sram Truvita Team GXP English. I had no trouble changing out the worn
    out OEM Sram GXP BSA 10-4, but I'm at a loss on how to select the
    correct ISIS BB.

    Any help will be appreciated.

    --
    C'est bon
    Soloman

    Check out the crank manufacturer's page on that product for
    recommended spindle length.

    I couldn't find anything about a cartridge BB specifically on a
    Catrike.

    My confusion was establishing the proper overall cartridge length from
    my shell width, which is 68mm. I see 68 x 108, 68X113, 68X118. It
    seems to me that the differences will only involve the chainline,
    which shouldn't matter too much because my chainlines run through
    idlers, but still I want to minimize chain deflection. Sheldon's
    website solved the problem for me. Triples and singles use the 113s.

    --
    C'est bon
    Soloman

    Sorry I meant crank manufacturer, not frame.
    The general rule for crank bearings is, 'Thread matches
    frame, spindle length matches crank.'

    Older cranks have a straight outer face and use spindles
    with a longer right side, that dimension varying by where
    the chainrings sit in relation to the crank arm mount. The
    variants are mind-numbingly numerous and complex:

    https://www.yellowjersey.org/photosfromthepast/CABB1986.JPG


    Modern cranks (which includes ISIS and Octalink) from
    roughly 1990 on curve from pedal seat to crank mount:

    http://www.yellowjersey.org/photosfromthepast/curve.jpg

    which makes shorter spindles possible along with L-R spindle
    symmetry and dramatically fewer spindle formats.

    For all spindles, new or old, consult crank manufacturer's
    recommended spindle dimensions. There are often two lengths
    listed, for 42mm or 45mm chainline usually, either of which
    is fine for your very long chain runs.



    --
    Andrew Muzi
    [email protected]
    Open every day since 1 April, 1971

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