Mixing road and off road gears

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?

 

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

 

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

 

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
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"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

 

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

 

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

 

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

 

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

 

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

 

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