Rear Der Top Pulley

Quoted message said:

I have a little chain skip occurring occasionally and was wondering if the top pulley on my 105
should float or not. I just replaced the pulleys and did not check to see what the original did.

The top one should float sideways, the bottom one should not. If your chain is skipping, I have to
ask whether you also replaced it or the cassette recently?

In article <[email hidden]>, George Maxwell

Quoted message said:

I have a little chain skip occurring occasionally and was wondering if the top pulley on my 105
should float or not. I just replaced the pulleys and did not check to see what the original did.

If you use indexed shifting (SIS) then the top pulley should float and the bottom should not. The
Shimano top pulleys often say "Centeron" on the side of the pulley.

If you use friction shifting it doesn't matter.

--Paul

I replaced the original pulleys on an LX rear derailleur with aftermarket ones and I noticed that
the top one was not only floating on it's bushing it was also turning on that bushing rather than on
the sealed bearing in the pulley. I think this nearly always happens with these pulleys. Anyway, I
filed away on the inside of the split bushing until the flanges were snug against the inside of the
sealed bearing, put washers on each side to fill in the gaps, and tightened up the screw so that I
have a fixed top pulley. The derailleur shifted just fine, at least as well as it ever had and maybe
a little better. Shimano began using that floating top pulley in the days before indexing (I have
some old derailleurs from that era and they have floating top pulleys). I think it is retained now
as a marketing thing, in my experience it certainly doesn't improve shifting. Indeed, why should it?
it seems to me it would just make the derailleur shift later because the shifter has to take up the
slack before the pulley actually begins moving the chain toward the next cog.

Bob Taylor

[email hidden] (Paul Southworth) wrote in message
news:<[email hidden]>...

Quoted message said:

In article <[email hidden]>, George Maxwell

Quoted message said:

I have a little chain skip occurring occasionally and was wondering if the top pulley on my 105
should float or not. I just replaced the pulleys and did not check to see what the original did.

If you use indexed shifting (SIS) then the top pulley should float and the bottom should not. The
Shimano top pulleys often say "Centeron" on the side of the pulley.

If you use friction shifting it doesn't matter.

--Paul

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

Quoted message said:

I replaced the original pulleys on an LX rear derailleur with aftermarket ones
. The derailleur shifted just fine, at least as well as it ever had and maybe a little better.
Shimano began using that floating top pulley in the days before indexing (I have some old
derailleurs from that era and they have floating top pulleys). I think it is retained now as a
marketing thing, in my experience it certainly doesn't improve shifting.

I did the silly upgrade to aftermarket pulleys once, myself. Silly, since they cost half as much as
a new derailer. I had hoped that the lack of float in the pulley would compensate for some of the
slop the worn derailer had accumulated. It worked, to a certain extent, but a new derailer is a
better solution.

It seemed to me that non-floating derailers were a little more precise, but much more finicky with
setup. Perhaps the floating derailers were introduced/kept to make adjustment less critical and to
allow some derailer movement when the chain is not.

I did not replace anything except the pulleys as the old ones were making annoying noises. The
replacements are Performance 11 tooth pulleys with washers to take up the space on either side of
the pulley. I needed two on each side to have them fit correctly in their place. Maybe remove one
from each side of the top one to allow a little float?

George

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

Quoted message said:

Quoted message said:

I have a little chain skip occurring occasionally and was wondering if

the

Quoted message said:

Quoted message said:

top pulley on my 105 should float or not. I just replaced the pulleys

and

Quoted message said:

Quoted message said:

did not check to see what the original did.

The top one should float sideways, the bottom one should not. If your chain is skipping, I have to
ask whether you also replaced it or the cassette recently?

The top pully on Shimano derailers are supposed to float.

Shuimano calls (called) it "Centeron". Basically, it allows for a little slop in the shifter
adjustment and lets the chain track correctly onto the cog.

May you have the wind at your back. And a really low gear for the hills! Chris

Chris'Z Corner "The Website for the Common Bicyclist": geocities.comczcornerOpen ↗