chain length

neeb
neeb Posts: 4,470
edited March 2010 in Workshop
I use this site to calculate chain length when I am fitting a new chain:

http://www.machinehead-software.co.uk/b ... hcalc.html

This time I am fitting a Campagnolo 53/39 chainset to a bike with 407mm chainstays. Most of the time I'll be using a 12-25 cassette but I'll be switching to a 12-27 when I need it. Would I be better off with 54 links or 53?

The older version of this program used to round to the nearest value, so would have recommended 53 links in both cases. The new version rounds up, so recommends 54 links for a total required length of 53.31 inches for the 53/27 combination.

Comments

  • keef66
    keef66 Posts: 13,123
    I use the practical method; run the chain round the biggest chainring and biggest sprocket but not through the rear mech, and add two links.

    I think I have also seen a method involving biggest chainring, smallest sprocket and through the rear mech, at which point the two jockey wheels should be vertically aligned.
  • redddraggon
    redddraggon Posts: 10,862
    Small chainring, small sprocket, rear mech should just be able to take up the slack.

    The BEST way of determining chain length.
    I like bikes...

    Twitter
    Flickr
  • neeb
    neeb Posts: 4,470
    If the mech can comfortably take up the slack for 54 links on small ring/small sprocket I guess that'll be right then.
  • redddraggon
    redddraggon Posts: 10,862
    neeb wrote:
    If the mech can comfortably take up the slack for 54 links on small ring/small sprocket I guess that'll be right then.

    If it'll just about take up the slack, yeh.

    It depends whether you want the longest chain or the shortest chain possible.
    I like bikes...

    Twitter
    Flickr