Mixing road and off road gears

Discussion in 'UK and Europe' started by Bert Smith, Apr 16, 2003.

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  1. Bert Smith

    Bert Smith Guest

    Does anyone know if you can put a 9spd Shimano Derore/XT/XTR casssette onto a 9spd Ultrega road hub,
    and still have the STI shifters work? If it is possible, do you need a road or MTB rear mech?
     
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  2. David Nutter

    David Nutter Guest

    Bert Smith <[email protected]> said:
    > Does anyone know if you can put a 9spd Shimano Derore/XT/XTR casssette onto a 9spd Ultrega road
    > hub, and still have the STI shifters work? If it is possible, do you need a road or MTB rear mech?

    Though it isn't exactly the same I'm using a Deore LX cassette with an Ultegra rear mech and bar-end
    shifters (not STI levers) and the indexing is fine.

    Regards,

    -david
     
  3. Pete Biggs

    Pete Biggs Guest

    Bert Smith wrote:
    > Does anyone know if you can put a 9spd Shimano Derore/XT/XTR casssette onto a 9spd Ultrega road
    > hub, and still have the STI shifters work?

    Yes, Shimano 9sp road and MTB equipment share the same splines, index and cable pull. Might possibly
    be a problem with mech or chain length depending on the cassette ratios...........

    > If it is possible, do you need a road or MTB rear mech?

    A road long-cage or "triple" mech might cope (in some cases, even a short-cage ouble one can). I
    would try it with existing mech first, then replace if necessary.

    Tip: If get problems in bottom gear(s) because of any larger sprockets, after ensuring b-screw is
    adjusted and chain is as short as reasonably possible, consider using a smaller outer chainring to
    enable an even shorter chain to be used. (Shorter chain pulls mech away from the sprockets).

    ~PB
     
  4. Msa

    Msa Guest

    Bert Smith <[email protected]> wrote in message
    news:[email protected]...
    > Does anyone know if you can put a 9spd Shimano Derore/XT/XTR casssette onto a 9spd Ultrega road
    > hub, and still have the STI shifters work? If it is possible, do you need a road or MTB rear mech?

    If nobody answers post on rec.bicycles.tech

    You'll def. get an answer there.

    --
    Mark
    ____________________________
    Practice does not make perfect... Perfect practice makes perfect

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    Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com).
    Version: 6.0.465 / Virus Database: 263 - Release Date: 25/03/03
     
  5. Peter B

    Peter B Guest

    "Bert Smith" <[email protected]> wrote in message
    news:[email protected]...
    > Does anyone know if you can put a 9spd Shimano Derore/XT/XTR casssette onto a 9spd Ultrega road
    > hub, and still have the STI shifters work? If it is possible, do you need a road or MTB rear mech?

    Yes. I actually did this last year for a one-off road ride in the Peak District.

    I "borrowed" the LX 11-32 cassette and XT rear mech from my MTB and fitted them to my Ultegra
    equipped road bike. (In fact it was a new cassette and a new chain was used, after the ride these
    went back onto the MTB and the road kit went back onto the road bike).

    Setting up was hassle free and it performed flawlessly. I shall probably do the same later
    this year.

    Prior to that I tried the 11-32 cassette with the Ultegra rear but on the 28 cog up the top jockey
    wheel teeth engaged those on the cogs. The Ultegra mech can handle a 27 cog reliably and some say
    bigger but the faffing about wouldn't be worth it IMHO, I'd sooner buy a new MTB rear mech even if I
    couldn't afford top quality, at least it would be easy to set up and function reliably .

    Pete
     
  6. Pete Biggs <pLime{remove_fruit}@biggs.tc> wrote in message
    news:[email protected]...
    > Bert Smith wrote:
    > > Does anyone know if you can put a 9spd Shimano Derore/XT/XTR casssette onto a 9spd Ultrega road
    > > hub, and still have the STI shifters work?
    >
    > Yes, Shimano 9sp road and MTB equipment share the same splines, index and cable pull. Might
    > possibly be a problem with mech or chain length depending on the cassette ratios...........
    >
    > > If it is possible, do you need a road or MTB rear mech?
    >
    > A road long-cage or "triple" mech might cope (in some cases, even a short-cage ouble one can). I
    > would try it with existing mech first, then replace if necessary.
    >
    > Tip: If get problems in bottom gear(s) because of any larger sprockets, after ensuring b-screw is
    > adjusted and chain is as short as reasonably possible, consider using a smaller outer chainring to
    > enable an even shorter chain to be used. (Shorter chain pulls mech away from the sprockets).
    >

    I found, using STI, an Ultegra triple rear mech and 11-32 cassette, that the top jockey was just
    slightly rubbing when on 32T. It worked, but the jockey probably wouldn't have lasted all that long.
    This was using a chain as short as would go over the big/big combination. I didn't fiddle much with
    the b-screw, but just got an XT mech, which was fine with no other changes. Based on this, I would
    guess that 30T will be OK, 34T will definitely need an MTB rear mech. With 32T, you may fiddle more
    successfully than I did.

    I don't believe that changing the chainrings will do any good. If the chain is as short as will go
    over the ring/sprocket, then the mech is pulled as far forwards (and away from the sprockets) as it
    will go. Having a smaller chainring will just mean it is stretched out in a slightly more upwards
    direction, closer to the sprockets.

    Andrew
     
  7. Pete Biggs

    Pete Biggs Guest

    Andrew Sweetman wrote:
    > I don't believe that changing the chainrings will do any good. If the chain is as short as will go
    > over the ring/sprocket, then the mech is pulled as far forwards (and away from the sprockets) as
    > it will go. Having a smaller chainring will just mean it is stretched out in a slightly more
    > upwards direction, closer to the sprockets.

    Missing the point, I think... Having a smaller chainring means you can remove a link or two from the
    chain (if chainring is enough smaller) which in turn means the mech can be pulled further away.

    ~PB
     
  8. Pete Biggs <pLime{remove_fruit}@biggs.tc> wrote in message
    news:[email protected]...
    > Andrew Sweetman wrote:
    > > I don't believe that changing the chainrings will do any good. If the chain is as short as will
    > > go over the ring/sprocket, then the mech is pulled as far forwards (and away from the sprockets)
    > > as it will go. Having a smaller chainring will just mean it is stretched out in a slightly more
    > > upwards direction, closer to the sprockets.
    >
    > Missing the point, I think... Having a smaller chainring means you can remove a link or two
    > from the chain (if chainring is enough smaller) which in turn means the mech can be pulled
    > further away.
    >

    Not at all. The length of the chain per se has nothing to do with what gears you can use, but only
    the amount of slack chain that the mech is trying to take up. Once you're down to no slack, that's
    your limit. I said "as short as will go ". Try thinking of having chainstays an inch shorter or
    longer. Will that affect what gears you can successfully use?

    Andrew
     
  9. Pete Biggs

    Pete Biggs Guest

    Andrew Sweetman wrote:

    >>> I don't believe that changing the chainrings will do any good. If the chain is as short as will
    >>> go over the ring/sprocket

    What ring/sprocket?

    A chain that is as short as possible for bottom gear would be virtually unusable for other gears if
    the bike has more than one chainring. So the chain has to be longer than that.

    >>>, then the mech is pulled as far forwards (and away from the sprockets) as it will go. Having a
    >>>smaller chainring

    Which chainring? I'm talking about the OUTER ring (of a double or triple system) - which is not
    actually used for bottom gear. (The practice is not applicable to single chainset bikes). And I'm
    talking about BOTTOM gear performance, ie. smallest front chainring with largest rear sprocket.

    >>> will just mean it is stretched out in a slightly more upwards direction, closer to the
    >>> sprockets.
    >>
    >> Missing the point, I think... Having a smaller chainring means you can remove a link or two
    >> from the chain (if chainring is enough smaller) which in turn means the mech can be pulled
    >> further away.
    >>

    > Not at all.

    I might be going bonkers but I still don't think you've got my point.

    > The length of the chain per se has nothing to do with what gears you can use, but only the amount
    > of slack chain that the mech is trying to take up. Once you're down to no slack, that's your
    > limit. I said "as short as will go ".

    Short as will go for what? This is the key. The chain needs to be LONG enough for the big-big
    otherwise something will explode when in that combination. (The big-big should normally be avoided
    but it's important that the derailleur can cope in the event of accidental shift). Make the "big"
    smaller and the chain can be made shorter.

    From the beginning, step by step:

    A chain that is too long can cause the upper jockey wheel to foul the largest sprocket when in
    bottom gear. After adjusting the b-tension screw, a way to solve this problem is to shorten the
    chain - IF that is possible. A way to make that possible, is to fit a smaller outer chainring. The
    size of the outer ring obviously has no direct effect on bottom gear performance but it means you
    can get away with using a shorter chain (if ring is enough smaller to remove a link or more) - which
    /can/ have a useful effect. Often, just one link is enough.

    > Try thinking of having chainstays an inch shorter or longer. Will that affect what gears you can
    > successfully use?

    Not in the way you mean, although shorter chainstays can affect the chainline and make more gears
    too crossed-over to use, but that's besides the point of course.

    ~PB
     
  10. Pete Biggs

    Pete Biggs Guest

    Pete Biggs wrote:
    > A chain that is as short as possible for bottom gear would be virtually unusable for other gears
    > if the bike has more than one chainring. So the chain has to be longer than that.

    Correction: .....unusable for some other normal gears from the other chainring(s).

    ~PB
     
  11. Pete Biggs

    Pete Biggs Guest

    Pete Biggs wrote:
    > A chain that is too long can cause the upper jockey wheel to foul the largest sprocket when in
    > bottom gear. After adjusting the b-tension screw, a way to solve this problem is to shorten the
    > chain - IF that is possible. A way to make that possible

    --if it chain is already as short as possible for the existing gears--

    > is to fit a smaller outer chainring. The size of the outer ring obviously has no direct effect on
    > bottom gear performance but it means you can get away with using a shorter chain (if ring is
    > enough smaller to remove a link or more) - which /can/ have a useful effect. Often, just one link
    > is enough.

    ~PB
     
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