Cassette modification question

Jasper Janssen said:

On 24 Nov 2006 17:06:06 -0800, "damyth" <[email hidden]>

Quoted message said:

Huh? where you going to get the 27t from? Sheldon's point was only
Ultegra and Dura Ace has 27t. (iirc 105 goes up to 25t.) You can
scour heaven and earth but you ain't going to find a Shimano 27t unless
it comes from Ultegra or Dura Ace cassette, and part of the spider to
boot.

There's a 105 12-27 in 10 speed, though, maybe Peter was thinking of that
one.

Jasper

Peter very well might be thinking of that one, but no "few minutes with
a punch" is ever going to render him a usable 27t sprocket from
Shimano, never mind a "loose 12-27 '105' cogset, since the 27t only
comes on spiders (9 or 10 spd).

Maybe Miche has it, I haven't checked, but you aren't going to get a
loose 27t cassette sprocket from Shimano, no way no how. 28t, on the
other hand, are plentiful.

Mike Jacoubowsky said:

The ramps are placed in a specific location to facilitate moving from one
cog (or chainring) to the next. They encourage the chain to shift at a
particular time (position on the cog), so that, when you're shifting to the
next-larger cog, the chain is moving up at the right time to catch a tooth
profile that's specifically made to engage an upshifting chain a bit more
readily. If your ramps aren't synchronized, this doesn't happen, and the
chain will be climbing up onto the next cog in a less-than-optimal position.

Have you ridden with an a la carte cassette? It works better than you
might think.

Matt O.

On 25 Nov 2006 21:19:32 -0800, "damyth" <[email hidden]>

Quoted message said:

Jasper Janssen said:

On 24 Nov 2006 17:06:06 -0800, "damyth" <[email hidden]>

Quoted message said:

Huh? where you going to get the 27t from? Sheldon's point was only
Ultegra and Dura Ace has 27t. (iirc 105 goes up to 25t.) You can
scour heaven and earth but you ain't going to find a Shimano 27t unless
it comes from Ultegra or Dura Ace cassette, and part of the spider to
boot.

There's a 105 12-27 in 10 speed, though, maybe Peter was thinking of that
one.

Quoted message said:

Peter very well might be thinking of that one, but no "few minutes with
a punch" is ever going to render him a usable 27t sprocket from
Shimano, never mind a "loose 12-27 '105' cogset, since the 27t only
comes on spiders (9 or 10 spd).

That's true, all 10sp cassettes have the last two on spiders. But you
might get a 105 27t, albeit on a spider, which contradicts the last half
of your paragraph quoted up top. But it's nitpicjy, that's true.

Quoted message said:

Maybe Miche has it, I haven't checked, but you aren't going to get a
loose 27t cassette sprocket from Shimano, no way no how. 28t, on the
other hand, are plentiful.

I suspect there are indeed third party ones available, if not from miche
then from the really specialised we-have-everything people.

Jasper