Mountain bike fork length/rake question

Discussion in 'Cycling Equipment' started by Andrew Lee, Jun 19, 2003.

Thread Status:
Not open for further replies.
  1. Andrew Lee

    Andrew Lee Guest

    I have '93 Stumpjumper FS that has a leaky (oil) Specialized Future Shock air/oil fork. It needs an
    overhaul, but I don't think the parts are available anymore, at least that's what I was told when I
    asked around locally, so I am thinking of replacing it. The fork is much shorter than current forks
    and has 2" (or less) of travel. I measured it at 415 mm long from axle center to crown race seat at
    full extension. Newer forks are longer. The Marzocchi MX's are 458 mm long for the 85 mm travel
    setup. I think that this would increase the head angle by about 2.3 degrees, which might give the
    bike too much trail if the offset is about the same. The pdf on the Marzocchi site didn't have the
    offset dimension on the drawing, but so I measured it off the drawing at about 41 mm (does that
    sound right if anyone knows?). This looks substantially more than the offset of my Future Shock, so
    perhaps the trail actually not be made too long by the longer fork. I don't know a good way to
    measure the offset of my fork though - the entire offset looks to be at the crown, with the dropouts
    in-line and centered with the sliders. It looks like the offset might only be about 15 mm+/-5 at the
    crown (it's kind of hard to judge the center of the steerer with it on the bike), so that would be
    good. But I really can't tell the crown is angled to provide additional offset. Anyone here know the
    offset of this old fork? ( I'm sure a lot of the shop owners here who were Specialized dealers sold
    bunches of these 10 years back.)

    Also what is a typical trail dimension for a neutral handling mountain bike? I'm guessing that it's
    a bit more than a typical road bike.

Thread Status:
Not open for further replies.