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Replacing chainset on my Tricross

rhextrhext Posts: 1,639
edited March 2010 in Workshop
I have a Specialized tricross, think it's a 2006. It's time to replace chain and cassette again and, while I'm at it, I'm tempted to do the chainset too. So I need to know what to buy. It's currently got a RPM double on it, with an internal bottom bracket. But since I've not yet dismantled it, I'm not sure whether it's octalink, ISIS, or square taper. Does anyone know?

Anyway, if it's square taper, I'm minded to replace the bottom bracket too. Am I correct in thinking that if I wanted to use an external bottom bracket, I'd need to get the BB shell faced at a bike shop?

And if I decide to stick with the internal, does anyone know which of the sizing options I'll need:

109, 113mm or 118mm spindle length (am going to get another double)
English or Italian thread?
68mm, 70mm or 73mm BB shell width?

I guess if the worst comes to the worst I can pull it apart to find out: but I don't want to run the risk of leaving the bike unserviceable while the new bits come!

Posts

  • John.TJohn.T Posts: 3,698
    It wont be Octalink but could be Isis or square. Probably square. You may be able to see this just behind the crank.
    Best to get the BB faced if going to external bearings but I did not on my Ribble and have had no problems.
    If you stick with the internal the length will be dictated by which chainset you go for. The shell is almost certainly 68mm English. Measure the shell width. 68mm is English, 70 is Italian and 73 is English MTB.
    You could of course just replace the rings. Plenty to go at here.
    http://www.spacycles.co.uk/products.php?plid=m2b0s149p0
  • rhextrhext Posts: 1,639
    John.T wrote:
    It wont be Octalink but could be Isis or square. Probably square. You may be able to see this just behind the crank.
    Best to get the BB faced if going to external bearings but I did not on my Ribble and have had no problems.
    If you stick with the internal the length will be dictated by which chainset you go for. The shell is almost certainly 68mm English. Measure the shell width. 68mm is English, 70 is Italian and 73 is English MTB.
    You could of course just replace the rings. Plenty to go at here.
    http://www.spacycles.co.uk/products.php?plid=m2b0s149p0

    Thank you, that's helpful. Will go and have a squint/measure. I thought about replacing the rings, but I'd be surprised if the old ones have not siezed (four years commuting in all weathers, and road salt is particularly unkind). And CRC have octalink double chainsets on such a big discount at the moment, it's probably cheaper to go for a replacement.
  • John.TJohn.T Posts: 3,698
    Octalink BBs only come in 4 sizes. English double or triple and Italian double or triple so that should be easy to sort out. Make sure you get a road one. MTB ones are a different spline. Wiggle have 105 at £18 ish.
    http://www.wiggle.co.uk/p/cycle/7/Shimano_105_5500_Octalink_Bottom_Bracket/4000000771/
    Be aware that this is old stock and future replacements could be a problem.
  • rhextrhext Posts: 1,639
    That's perfect. Am I right in assuming that the 109mm is double and the 118mm triple?
  • jgsijgsi Posts: 5,025
    YOu should be able to pick up a Shimano BB for less than a tenner.
    I put a 68-110 BB on when changed to a double chainset. 113 is adequate for a triple btw.
    Tricross' - cheap as chips to keep on going.... best thing about them.
    http://www.chainreactioncycles.com/Mode ... elID=34652
  • John.TJohn.T Posts: 3,698
    rhext wrote:
    That's perfect. Am I right in assuming that the 109mm is double and the 118mm triple?
    Yes. Those are the two Octalink sizes.
  • ex-pat scotex-pat scot Posts: 939
    my 2009 has a square taper BB.

    It's definitely a 68mm shell.

    I've just replaced the stock FSA chainset & BB with a FSA K force light mega exo set. DIdn't bother facing the shell threads/cups.

    I went for a compact (34-50) road set up rather than mtb triple.
    Commute: Langster -Singlecross - Brompton S2-LX

    Road: 95 Trek 5500 -Look 695 Aerolight eTap - Boardman TTe eTap

    Offroad: Pace RC200 - Dawes Kickback 2 tandem - Tricross - Boardman CXR9.8 - Ridley x-fire
  • rhextrhext Posts: 1,639
    Thank you for your help. I now have a plan!
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