Changing Cassette

Ian said:

I have been following the thread about the gears, however it went all over
the place.

Anyway my question is, if I change my cassette from a 12 - 25 to a 12 - 27,
will it cause any problems with smooth changing.
Is it just a simple changeover that won't cause any other problems ?

Ian

It should change fine. The only concern is whether your chain is long enough. A 27T rear cog takes up more chain. If the chain is not long enough, it will destroy your rear derailer. Check to ensure there is just enough chain in the big-big combination and you'll be fine. Not that you'll ever want to use the big-big combo, but it's nice to have enough chain to prevent yourself from accidentally wrecking your derailer.

Cheers,
Ritch

"Ian" <[email hidden]> wrote in message
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Quoted message said:

I have been following the thread about the gears, however it went all over
the place.

Anyway my question is, if I change my cassette from a 12 - 25 to a 12 -
27,
will it cause any problems with smooth changing.

Nope, just check the chain is long enough but you should be ok. Check out:
http://www.sheldonbrown.com/derailer-adjustment.html#chain

Quoted message said:

Is it just a simple changeover that won't cause any other problems ?

Yep

Adam

"Ian" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

I have been following the thread about the gears, however it went all over
the place.

Anyway my question is, if I change my cassette from a 12 - 25 to a 12 -
27,
will it cause any problems with smooth changing.
Is it just a simple changeover that won't cause any other problems ?

Ian

Shouldn't be a problem. Assuming you are running a double on the front and
a standard short cage derailleur. You may need a small adjustment to the
rear mech to stop it from hitting the bigger 27T sprocket and depending on
your current chain length you might need to add a couple of links.
Personally I've only had experience changing between cassettes with a 19T,
23T or 25T top end but I know a couple of people that run a 27T with a short
cage. Anything bigger than a 27T may need a different derailleur with a
longer cage.

Flyingdutch may be able to give you a better qualified answer when it comes
to the jump from 25T to 27T but I think he's currently running a long cage
derailleur.

Geoff

"Ian" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

I have been following the thread about the gears, however it went all over
the place.

Anyway my question is, if I change my cassette from a 12 - 25 to a 12 -

27,

Quoted message said:

will it cause any problems with smooth changing.
Is it just a simple changeover that won't cause any other problems ?

Ian

its a simple enough changeover if you have the tools.
its is a cassette right??? http://www.sheldonbrown.com/free-k7.html
the 2 biggest worries i can think of are, how old is the chain? it might be
to worn to fit a new cassette.
if it isn't worn, is the chain long enough to go big-big?
http://www.sheldonbrown.com/derailer-adjustment.html#chain
hope this helps

stu

"Geoff" <[email hidden]> wrote in message news:<[email hidden]>...

Quoted message said:

Anything bigger than a 27T may need a different derailleur with a
longer cage.

I've run either a 12-32 or an 11-30 cluster with an XT short cage, and
been able to use 22/32/42 chainrings with it. You can't go big-big and
still have usable tension in the lower gears, but unless you're really
mashing the shifter you can feel that the derailleur doesn't want to
go into a gear, and stop before you break it.

However, the XT short cage may have been the equivalent of a road
"medium cage". It's been so long since that derailleur went to the
parts bin I can't remember just how long the cage was.

Dave - who had about a year span of breaking a derailleur between
every 4 and 6 weeks. That was expensive.

Random Data said:

"Geoff" <[email hidden]> wrote in message news:<[email hidden]>...

Quoted message said:

Anything bigger than a 27T may need a different derailleur with a
longer cage.

I've run either a 12-32 or an 11-30 cluster with an XT short cage, and
been able to use 22/32/42 chainrings with it. You can't go big-big and
still have usable tension in the lower gears, but unless you're really
mashing the shifter you can feel that the derailleur doesn't want to
go into a gear, and stop before you break it.

However, the XT short cage may have been the equivalent of a road
"medium cage". It's been so long since that derailleur went to the
parts bin I can't remember just how long the cage was.

Dave - who had about a year span of breaking a derailleur between
every 4 and 6 weeks. That was expensive.

The instructions that come with Shimano derailluers tell you what sort
of gear sizes you can run. There's a little formula you have to work it
out.

I also had a bad run on derailluers and have a box with three brand new
ones on standby. Yes it is expensive. Since getting the spares a few
months ago I haven't had any failures, Touch Wood! (Touches head).

Marty

Thanks guys , much appreciatted.
"stu" <[email hidden]> wrote in message
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Quoted message said:

"Ian" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

I have been following the thread about the gears, however it went all

over

Quoted message said:

Quoted message said:

the place.

Anyway my question is, if I change my cassette from a 12 - 25 to a 12 -

27,

Quoted message said:

will it cause any problems with smooth changing.
Is it just a simple changeover that won't cause any other problems ?

Ian

its a simple enough changeover if you have the tools.
its is a cassette right??? http://www.sheldonbrown.com/free-k7.html
the 2 biggest worries i can think of are, how old is the chain? it might

be

Quoted message said:

to worn to fit a new cassette.
if it isn't worn, is the chain long enough to go big-big?
http://www.sheldonbrown.com/derailer-adjustment.html#chain
hope this helps

stu