8 Speed/9 Speed mixture on MTB

Discussion in 'UK and Europe' started by Candt, Feb 14, 2003.

Thread Status:
Not open for further replies.
  1. Candt

    Candt Guest

    Without wanting to incur the wrath of the newsgroup purists (you know who you are), I need to ask a
    technical question, but one specific to MTB's, so I'm asking here rather than rec.bicycles.tech...

    I had an 8 speed bike... STX 8 speed shifters, 8 speed cassette... I was recently talked into buying
    an XT front mech by my wife (her brother was working in the shop, and told me I had to buy something
    to make him look good - how cool is that!!)

    Now, because the XT mech was incompatible with my crappy chainrings (24-34-42), I bought a set of
    deore hollowtech 22-32-44 9-speed rings with cranks, and of course - the essential XT rear mech
    too.... (This shop had 35% off a bunch of shimano stuff - so it was a great price)

    Now, I'm quite good at setting up gearing, and I bought a new BB to improve the chainline which was
    too wide at the front with the lower profile cranks, and am basically there, all gears can be
    shifted into. The trouble is - the chain just about rubs on the front derailleur on one side of the
    other. ie Lets say your in the middle chainring, if the chain is just touching one side on the 1st
    cassette cog, I can tighten the cable so its not, but then it will touch on the 8th cog...

    Now I know a 9 speed cassette would be preferable, and matching shifters too - but I've already
    spent the budget on these other parts, and I thought that a 9 speed cassette is the same high to low
    width than 8 speed, its just the spacing which is different. So - the only thing I can think of is
    that the chain is too thick...

    So in my usual round about way - all I need to know is - will a 9-speed chain help? Is it indeed
    thinner, as I only need to save about 1mm to prevent the rubbing? and will a 9-speed chain work with
    an 8-speed cassette?

    Cheers then

    CandT
     
    Tags:


  2. CandT <[email protected]> wrote

    > Now, because the XT mech was incompatible with my crappy chainrings (24-34-42), I bought a set of
    > deore hollowtech 22-32-44 9-speed rings with cranks, and of course - the essential XT rear mech
    > too.... (This shop had 35% off a bunch of shimano stuff - so it was a great price)
    >
    > Now, I'm quite good at setting up gearing, and I bought a new BB to improve the chainline which
    > was too wide at the front with the lower profile cranks, and am basically there, all gears can be
    > shifted into. The trouble is - the chain just about rubs on the front derailleur on one side of
    > the other. ie Lets say your in the middle chainring, if the chain is just touching one side on the
    > 1st cassette cog, I can tighten the cable so its not, but then it will touch on the 8th cog...

    I have never been able to adjust my front mech on an 8-speed system so using the middle ring, that
    it reaches all 8 rear cogs without rubbing. I set it up so that I can easily get the smallest 4-5
    cogs with the big ring, all but the smallest cog with the middle ring (want to avoid using the
    smallest cog as it will wear out so quickly) and the largest 4-5 cogs on the small ring.

    You could try to spread out the cage of the front mech a bit, I suppose, but I'd be happy with what
    you've already achieved.

    I don't think a narrower 9-speed chain is a good idea. It probably won't work well on an 8-speed
    cassette (but I haven't tried it) and it will wear out more quickly.

    -Myra
     
  3. [email protected] (Myra VanInwegen) wrote
    > I have never been able to adjust my front mech on an 8-speed system so using the middle ring, that
    > it reaches all 8 rear cogs without rubbing.

    <snip>

    Same here. When I got the bike it was fine, but when I had to replace my front mech cable it went to
    pot. Even the bike shop couldn't fix
    it. I can have no-rub on most combinations, but rub on others, or visa-versa. I'm taking a
    large pair of pliers to it when I can be bothered - anything Shimano can do, I can do with
    a mole wrench!
     
  4. stephen pridgeon <[email protected]> wrote in message
    news:[email protected]...
    > [email protected] (Myra VanInwegen) wrote
    > > I have never been able to adjust my front mech on an 8-speed system so using the middle ring,
    > > that it reaches all 8 rear cogs without rubbing.
    >
    > <snip>
    >
    > Same here. When I got the bike it was fine, but when I had to replace my front mech cable it went
    > to pot. Even the bike shop couldn't fix
    > it. I can have no-rub on most combinations, but rub on others, or visa-versa. I'm taking a large
    > pair of pliers to it when I can be bothered - anything Shimano can do, I can do with a mole
    > wrench!

    IME it's a sure sign that the mech is wearing - I've had this a few times now (I'm just about to put
    my 4th front mech on my mtb) and every time I can set it up perfectly with a new mech but not with
    the old one. If you try wiggling the mech cage you can see the wear fro yourself - there shouldn't
    be any movement.

    Anyone know if XTR has more adjustment than XT ? I'm thinking I might be able to delay the
    onset that way.

    Russ
     
  5. "Russell Pinder" <[email protected]> wrote in message
    news:[email protected]...
    >
    > stephen pridgeon <[email protected]> wrote in message
    > news:[email protected]...
    > > [email protected] (Myra VanInwegen) wrote
    > > > I have never been able to adjust my front mech on an 8-speed system
    so
    > > > using the middle ring, that it reaches all 8 rear cogs without rubbing.
    > >
    > > <snip>
    > >
    > > Same here. When I got the bike it was fine, but when I had to
    replace
    > > my front mech cable it went to pot. Even the bike shop couldn't fix
    > > it. I can have no-rub on most combinations, but rub on others, or visa-versa. I'm taking a
    > > large pair of pliers to it when I can be bothered - anything Shimano can do, I can do with
    > > a mole wrench!
    >
    > IME it's a sure sign that the mech is wearing - I've had this a few
    times
    > now (I'm just about to put my 4th front mech on my mtb) and every time
    I can
    > set it up perfectly with a new mech but not with the old one. If you
    try
    > wiggling the mech cage you can see the wear fro yourself - there
    shouldn't
    > be any movement.
    >
    > Anyone know if XTR has more adjustment than XT ? I'm thinking I might
    be
    > able to delay the onset that way.
    >

    I binned one XTR mech trying to solve that problem (among others) and concluded (along with several
    bike shops) that it is a characteristic of the beast. In short, XTR does it too - and from fresh out
    of the box.

    Of course if the BB and hubs are using rubble for bearings a certain loss of precision in the drive
    train is inevitable.

    Peter
     
Loading...
Thread Status:
Not open for further replies.
Loading...