Rear Mech

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

Quoted message said:

I have a Shimano STX-RC 8-speed rear mech (circa 1998) with an 11-28t
cassette. I am considering a conversion to Megarange 11-34t. Does
anybody
happen to know if my present mech would be compatible. If not, any
suggestions as to a replacement of equivalent quality.

In theory, the maximum range on the back is 22T. Since you're only exceeding
this by 1T, it's worth a try. The overall range (front and rear) is 43T, so
you'll need to check that your front rings don't have a greater difference
than 20T. It shouldn't be much more, and, again, if it's close you'll
probably get away with it - although your chain will be a bit loose is
small>small, or too short (ouch, potentially) big>big.

jeffbee said:

I have a Shimano STX-RC 8-speed rear mech (circa 1998) with an 11-28t
cassette. I am considering a conversion to Megarange 11-34t. Does anybody
happen to know if my present mech would be compatible.

I don't know if it's compatible, but I have observed that Megarange seem
to look good on paper but be somewhat miffing to their users when it
comes down to actually pedalling the beasts because the end jump is so
big it actually robs you of a useful gear more often than it gives you one.

So I'd personally be inclined to avoid Megarange and if you really want
a whopping granny then change things for smaller at the front if you can.

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net [email hidden] http://www.dundee.ac.uk/~pjclinch/

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

Quoted message said:

I'd personally be inclined to avoid Megarange and if you really want a
whopping granny then change things for smaller at the front if you can.

Having said it's compatible, I would agree wholeheartedly with Peter's
comment.

jeffbee said:

I have a Shimano STX-RC 8-speed rear mech (circa 1998) with an 11-28t
cassette. I am considering a conversion to Megarange 11-34t. Does
anybody happen to know if my present mech would be compatible.

I would expect problems with that mech but it's worth a try first. Have
the chain as short as possible for the big ring + big cog to work.

Quoted message said:

If not, any suggestions as to a replacement of equivalent quality.

Shimano Deore

~PB

Simon D said:

In theory, the maximum range on the back is 22T. Since you're only
exceeding this by 1T, it's worth a try. The overall range (front and
rear) is 43T, so you'll need to check that your front rings don't
have a greater difference than 20T.

The more important specification is Maximum Sprocket which is a different
spec to Capacity (small-small combinations can be avoided to avoid
problems with that).

I don't have the Max info to hand for the STX but I suspect it's 28 or
30T.

~PB

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

Quoted message said:

The more important specification is Maximum Sprocket which is a different
spec to Capacity (small-small combinations can be avoided to avoid
problems with that).

I don't have the Max info to hand for the STX but I suspect it's 28 or
30T.

It's 34T. If one thinks about it, it couldn't be much less with a rear
capacity of 22T - unless one uses 10T sprockets, of course! ;-)

BUT - I am assuming that this is the long cage version of the STX RC. There
was a short cage version, too, which resembled a road mech. The max sprocket
*would* then be 30T, and the other capacities would be much less, too. The
long cage version was by far the more common, though.

Peter Clinch said:

I don't know if it's compatible, but I have observed that Megarange
seem
to look good on paper but be somewhat miffing to their users when it
comes down to actually pedalling the beasts because the end jump is so
big it actually robs you of a useful gear more often than it gives
you one.

I could imagine feeling the urge for one if I lived at the top of a steep
hill but cycled mainly on flatter roads.

~PB

Pete Biggs said:

I could imagine feeling the urge for one if I lived at the top of a steep
hill but cycled mainly on flatter roads.

In theory I agree, but in practice hills in an area tend to come in
herds with different flavours amongst the individuals. I'm sure there
are places somewhere where it's Just The Thing, but observations to date
suggests that Megarange is primarily very handy on paper, as opposed to
the back of a bike...

Roos had one on the back of a hire bike in Vancouver last year, and
there are some /very/ nasty hills there. IIRC the MR tended to involve
hills that ended up getting the bike pushed up them anyway, and it's
trickier to switch into when you're on a roll because of the huge jump.
It's the taking out of what would be your next sensibly stepped lower
gear that I don't like, especially when I retain the pushing option for
a really killer hill!

Aside from this, my skepticism is fuelled by something of a lack of
"these MR cassettes are great!" statements, but it could be my memory is
just being selective here, nudged that way by Jon saying he was
underwhelmed with the one on his 'bent on Saturday.

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net [email hidden] http://www.dundee.ac.uk/~pjclinch/

Many thanks for all the responses. I'm now beginning to think twice!

John

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

Quoted message said:

jeffbee said:

I have a Shimano STX-RC 8-speed rear mech (circa 1998) with an 11-28t
cassette. I am considering a conversion to Megarange 11-34t. Does
anybody happen to know if my present mech would be compatible.

I would expect problems with that mech but it's worth a try first. Have
the chain as short as possible for the big ring + big cog to work.

Quoted message said:

If not, any suggestions as to a replacement of equivalent quality.

Shimano Deore

~PB

Pete Biggs said:

I don't have the Max info to hand for the STX but I suspect
it's 28 or 30T.

http://www.fa-technik.adfc.de/Komponenten/Schaltwerk/index.html

gives

Shimano RD-MC38 SGS 8 32 11 20 39 -

In other words, 32 big, 11 small, 20 difference, 39 total.

I suspect it'll reach the 34 without much trouble.

http://www.fa-technik.adfc.de/Hersteller/Shimano/DIGEST.html
is a rich seam of information on older Shimano components, including
exploded diagrams of many of the parts, some of which include specs. It
pays to know a little German, but most of the important information can be
deduced by context.

James Thomson