SRAM Road Cassette Chainline Issues

I just replaced my 12-23 Ultegra cassette with a 12-26 SRAM cassette (
I moved to the mountians and I'm too big a wuss to turn over the 23 on
some of the climbs around here).

On the Ultegra, I only got chain rub on the big gear in the 39-12, but
on the SRAM, i get rubbing in the 39-12,13,14 (or is it 15, either way
its the 3 smallest cogs). I also replaced the chain with the new
cassette.

Is it possible that changing the make of the cassette altered my
chainline? If so, what's the solution (ignore, BB spacer, re-space
the hub, buy a Shimano cassette)?

Ted C.

Try adjusting the derailleur out just a little .Its hard to believe that the
cassette is wider than your original.but problem is .So I would try the adj
screws a couple turns and see what happens.

Jamie TrailBlazer At Large wrote:
Try adjusting the derailleur out just a little .Its hard to believe that the
cassette is wider than your original.but problem is .So I would try the adj
screws a couple turns and see what happens.

I think he's saying the chain is rubbing on the big chainring, not the
front der. Adjusting the der will have no effect on that.

Art Harris

ejcookso wrote:
I just replaced my 12-23 Ultegra cassette with a 12-26 SRAM cassette ( I
moved to the mountians and I'm too big a wuss to turn over the 23 on
some of the climbs around here).
On the Ultegra, I only got chain rub on the big gear in the 39-12,
but on the SRAM, i get rubbing in the 39-12,13,14 (or is it 15,
either way its the 3 smallest cogs). I also replaced the chain with
the new cassette.
Is it possible that changing the make of the cassette altered my
chainline? If so, what's the solution (ignore, BB spacer, re-space the
hub, buy a Shimano cassette)?
Ted C.


I doubt that the cassette is at fault... it can only change th
chainline slightly by moving in or out on the cassette body. However
if it is a few .1s of a mm wider than your previous casette, it wil
want the chain to be further out... and this does change the angle o
the chain slightly. Cassette bodies and cassettes each hav
manufacturing tolerances. Some cassettes and cassette bodies ar
oversized or undersized. You may be dealing with an oversized cassette
Since you also replaced the chain, I would focus on the details of th
outer dimensions of the chain itself... especially compared to what yo
had before. There are differences in the outer dimensions of variou
chains. Cross chaining in the gears you are talking about should b
avoided. You should be able to get close to the same effective rati
without cross chaining


-

On Thu, 27 May 2004 13:00:37 GMT, Harris
wrote:

Jamie TrailBlazer At Large wrote:
Try adjusting the derailleur out just a little .Its hard to believe that the
cassette is wider than your original.but problem is .So I would try the adj
screws a couple turns and see what happens.

I think he's saying the chain is rubbing on the big chainring, not the
front der. Adjusting the der will have no effect on that.

Art Harris

Yes, its the big ring thats rubbing. The deraillieur would've been
easy.

Ted C

I don't think this has anything to do with thew new cassette. I have
used SRAM road cassettes for a few years now and it is my experience
that they are identical in width and alignment on Shimano splined
wheels. I honestly suspect that with a new, rigid chain, your chain
line is more direct (chains get sloppy side to side with wear too), and
that once the chain breaks in, you will get at least the third cog in
and perhaps second over time. I notice this every time I put a new
chain on and it clears up after about 300 miles.

Good luck!

Terry

daveornee wrote:
ejcookso wrote:
I just replaced my 12-23 Ultegra cassette with a 12-26 SRAM cassette ( I
moved to the mountians and I'm too big a wuss to turn over the 23 on
some of the climbs around here).
On the Ultegra, I only got chain rub on the big gear in the 39-12,
but on the SRAM, i get rubbing in the 39-12,13,14 (or is it 15,
either way its the 3 smallest cogs). I also replaced the chain with
the new cassette.
Is it possible that changing the make of the cassette altered my
chainline? If so, what's the solution (ignore, BB spacer, re-space the
hub, buy a Shimano cassette)?
Ted C.



I doubt that the cassette is at fault... it can only change the
chainline slightly by moving in or out on the cassette body. However,
if it is a few .1s of a mm wider than your previous casette, it will
want the chain to be further out... and this does change the angle of
the chain slightly. Cassette bodies and cassettes each have
manufacturing tolerances. Some cassettes and cassette bodies are
oversized or undersized. You may be dealing with an oversized cassette.
Since you also replaced the chain, I would focus on the details of the
outer dimensions of the chain itself... especially compared to what you
had before. There are differences in the outer dimensions of various
chains. Cross chaining in the gears you are talking about should be
avoided. You should be able to get close to the same effective ratio
without cross chaining.



--

ej- I also replaced the chain with the new
cassette. BRBR

9s chain? sounds like ya might have a 8s one. Some bike shops say they are
cross compatible, 8s with a 9s cogset and the reverse but nope.

Peter Chisholm
Vecchio's Bicicletteria
1833 Pearl St.
Boulder, CO, 80302
(303)440-3535
http://www.vecchios.com
"Ruote convenzionali costruite eccezionalmente bene"

wrote:
I just replaced my 12-23 Ultegra cassette with a 12-26 SRAM cassette.
On the Ultegra, I only got chain rub on the big gear in the 39-12, but
on the SRAM, i get rubbing in the 39-12,13,14 (or is it 15, either way
its the 3 smallest cogs). I also replaced the chain with the new
cassette.

I don't see how it's possible that a new cassette would change your chainline
by 2 whole gears (9-10 mm). Something else must have changed.

--
Dave
dvt at psu dot edu

9s chains vary a little (6.2-6.8) but is it possible that your new chain is
noisier? I use the cassette you mention with much satisfaction. (Sram 89R
hollow pin 6.2mm)
Tom
--
Bruni Bicycles
"Where art meets science"
brunibicycles.com
410.426.3420
dvt wrote in message
...
wrote:
I just replaced my 12-23 Ultegra cassette with a 12-26 SRAM cassette.
On the Ultegra, I only got chain rub on the big gear in the 39-12, but
on the SRAM, i get rubbing in the 39-12,13,14 (or is it 15, either way
its the 3 smallest cogs). I also replaced the chain with the new
cassette.

I don't see how it's possible that a new cassette would change your
chainline
by 2 whole gears (9-10 mm). Something else must have changed.

--
Dave
dvt at psu dot edu