Cassette replacement

Discussion in 'Cycling Equipment' started by roo142, Jun 26, 2004.

  1. roo142

    roo142 New Member

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    I have an old raliegh road bike that I am upgrading and replacing all of the old hardware. I want to replace the 7 gear cassette and get a newer 8 or 9 gear. I am getting new wheel sets. Are there any frame size width issue that are going to interfere?
     
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  2. dennis dee

    dennis dee New Member

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    Current rear hub width is 130mm for road. Earlier hubs and frame rear tire hub spacing is narrower than this, usually 126mm for 7s.
     
  3. roo142

    roo142 New Member

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    Yep, It is 126mm. Are there any setups that will fit this width or am I kinda stuck with the 7
     
  4. dennis dee

    dennis dee New Member

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    On some steel frames with 126mm you can still squeeze a 130mm hub thru it. But this does not guarantee you'll get good clearance on the small cog. It's a boon if you do get the clearance but it will be a bummer everytime you replace/re-mount the rear wheel. An option is to have the rear spread by a frame builder. You can try spreading the rear yourself if you are confident enough. I am of course assuming you have a steel frame. The site below has useful instructions on how to do this. Good luck.

    http://www.sheldonbrown.com/frame-spacing.html
     
  5. roo142

    roo142 New Member

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    Thank You
     
  6. nutbag

    nutbag New Member

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    I have eight speed Shimano on my 1988 Raleigh, and have no problems.

    I have been told that it can put a little bit more stress on the
    drop-outs, and could cause your derailleur to be a teeeny bit out of alignment, but like I said, I've had no problems.

    I plan on going to 9 speed when all my 8 speed levers die. When Shimano went to 9 speed, they moved to a narrower chain, so a 9 speed cassette is not the width of 8 old cogs plus 1, it's obviously narrower.

    As far as I know it's becoming harder and harder to get 8 speed stuff, so you might have to go 9 speed anyway -- besides, 9 speed levers look cooooler!

    So, I say go for it. Those strong old frames were built to last!!
     
  7. boudreaux

    boudreaux New Member

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    8 and 9 speed shimano casettes are interchangable on 8/9 speed shimano compatible hubs.Shimano 10 speed even works on shimano 8/9 hubs with a thin included spacer.
     
  8. nutbag

    nutbag New Member

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    I've just read on www.bikeforums.net that the overall width of a 9 speed Shimano cassette is only 1mm wider than the old 8 speed, becasue the 9 speed stuff uses a narrower chain and cogs.

    http://www.bikeforums.net/showthread.php?t=55763
    (see message #3)

    Sounds too good to be true, but I'm sure it would be easy enought ot find out.
     
  9. boudreaux

    boudreaux New Member

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    So what's the issue?
     
  10. nutbag

    nutbag New Member

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    I think he's concerned that a 9 speed cassette, or even an 8, would be too wide for his old Raleigh frame.
     
  11. boudreaux

    boudreaux New Member

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    If it's not 130 dropout spacing, and the frame is steel, it's not an issue.The frame can be spread, or the wider hub just dropped in and ridden.
     
  12. Mr_Potatohead

    Mr_Potatohead New Member

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    I have an older Raleigh Road bike with 126mm rear dropout spacing too.

    I just couldn't bear to part with a full Reynolds 753 team issue frame made in Nottingham just because it's 126mm spaced.
    But cold setting 753 tubing is not advisable. So...

    Here's the deal. Buy an older Shimano 7 speed cassette hub with the 126mm spacing. Then get a 9 speed Shimano 105 cassette. Remove the screws or rivets that hold the cassette together. Then mount eight of the nine cogs on your seven speed cassette. They fit perfectly. You can use a Shimano 105 or Ultegra or whatever 9 speed indexed shifter to shift by just adjusting it so the 9th position is locked out at the top of the range. See Sheldon Browns article.

    Harris Cyclery sells 126mm 7 speed freehubs too.

    http://sheldonbrown.com/k7.html#up7

    "8 Of 9 On 7

    Any 7-speed Shimano Hyperglide Freehub will actually work with 8 sprockets, without any modification! What you need to do is to use 8 of the sprockets from a 9-speed cassette, with the 9-speed spacers.

    To make this work, you'll also need to use a 9-speed chain and shifters. Your old 7-speed derailer should work OK if it isn't too badly worn. The limit stops on the derailer will cause the useless 9th position on the shifters to be locked out, so this will work as a perfectly normal 8-speed rig."
     
  13. nutbag

    nutbag New Member

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    It's my guess that if his bike is old 531, then it would be ok to ram in a nine speed. If it's not 531c, I think the rear triangle might not even be 531, but something even heavier and stronger.

    Infact..."a guy once told me........." that 753 was only 753 on the main tubes, and 531 for the seat and chain stays?? I might be getting it confused with the short-lived 708 tubes
     
  14. boudreaux

    boudreaux New Member

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    Duno what the issue supposedly is with 753 but it doesn't have to be cold set.Just spread the stays and drop a 130 in.It's only 2mm per side.
     
  15. Mr_Potatohead

    Mr_Potatohead New Member

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    I contacted Reynolds about doing just that. They said they've had fatigue failures in people who have done this.

    The issue with 753 is that it's heat treated so that the yield (set point) is much higher (and closer to ultimate) than regular Cro-Mo. This makes it stronger at the expense of fracture toughness.

    I actually found their exact response regarding doing this with 753 tubing.

    "when the wider hubs came into fashion, many riders tried to fit them.
    the
    problem they found was two fold.
    Either the SEATSTAY would buckle just below the bridge as the stays
    were
    opened wider, or the fit would look OK, and after a short while the
    CHAINSTAY would fail under fatigue near the BB shell due to the extra
    stress put on it."
     
  16. nutbag

    nutbag New Member

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    Wow, I thought that was a myth -- you know, one of those things you here in bike shops but never ever see in your whole life

    :)
     
  17. Mr_Potatohead

    Mr_Potatohead New Member

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    Just to reiterate, the problem is only with 753 tubing. Because it has been hardened so much it is stronger, thinner, and less ductile than convential cro-mo tubing.
     
  18. boudreaux

    boudreaux New Member

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    Still find it hard to believe,as there are plenty of other heattreated steels with the same characteristics.Spreading one enough to cold set it certainly involves alot more stress and bending than what's involved in just dropping in a 130 hub.
     
  19. Mr_Potatohead

    Mr_Potatohead New Member

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    Now that I think about it I think your right. I think the Reynolds rep was really referring to the cold setting process not the elastic spreading of the dropouts.
     
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