How do Jockey Wheels work?

www.visualthesaurus.com
search for cog-pulley-sprocket-wheel-journal-ect
and the thesuarus regular
coming from nowhere in knowledge about cycles, the pulley wheels'
disintegrative capacities intrigued me.
after sevral sets of "pulley wheels"
i come to the idea that the weels should be lubed with boat wheel
bearing grease frequently-try castrol at woolmort
the lube frequency on a one to one level with the tooth wear you will
and forecast experiencing
both should come out equal over the pulley wheels life time.
betting the drive train out of line reduces the life span no problem
bottom line- the pulley wheel needs maintenance but is like but more so
the other components ultimately disposable

www.visualthesaurus.com
search for cog-pulley-sprocket-wheel-journal-ect
and the thesuarus regular
coming from nowhere in knowledge about cycles, the pulley wheels'
disintegrative capacities intrigued me.
after sevral sets of "pulley wheels"
i come to the idea that the weels should be lubed with boat wheel
bearing grease frequently-try castrol at woolmort
the lube frequency on a one to one level with the tooth wear you will
and forecast experiencing
both should come out equal over the pulley wheels life time.
betting the drive train out of line reduces the life span no problem
bottom line- the pulley wheel needs maintenance but is like but more so
the other components ultimately disposable

Sheldon Brown said:

Speaking of the slop in the jockey pulley, this has never made a lot of
sense to me.

Indeed, in my own first S.I.S. derailer, I replaced the stock pulleys
with a pair of nice ball-bearing ones that I cannibalized from an old
Benelux derailer, with no detectable degradation of shifting function.

Do they offer /better/ quality (or performance) than today's pulleys
(which always strike me as a low point in a high-quality drivetrain)?
ie, would you recommend them if readily available. If not, why not?

If so, from where can they be acquired and for how much?

Thanks, Sheldon.

In article <[email hidden]>,

(Snoopy) te**yson@caverock.*et.*z (*is n) said:

I looked at a new SRAM derailleur at the LBS yesterday and alongside a
new Shimano derailleur and the upper guide pulley there was nowhere
near as much sideways movement in the former.

The question is if I stiffen up my derailleur to behave like a SRAM
derailleur, will I decrease the wear decrease the drivetrain noise and
improve the performance of my bicycle?

The reason the upper pulley has "float" is so the rear derailler has
less sensitivity to the cable tension being out of adjustment and
tolerates other wear/misalignment in the system. The floating pulley
automatically lines up with the cog above it. So if your cable tension
is a little off, or the derailler pivots wear a little, the floating
pulley accommodates some of the out of tolerance condition (i.e., slop)
in the system. I think you would not improve things by taking the float
out of the pulley.

--
Mike DeMicco <[email hidden]>

I blurted out:

Quoted message said:

Quoted message said:

Indeed, in my own first S.I.S. derailer, I replaced the stock pulleys
with a pair of nice ball-bearing ones that I cannibalized from an old
Benelux derailer, with no detectable degradation of shifting function.

Neil Brooks said:

Do they offer /better/ quality (or performance) than today's pulleys
(which always strike me as a low point in a high-quality drivetrain)?

I dunno. They do have nice adjustable ball bearings.

The jockey pulley has tall teeth like a sprocket, for tight lateral
control of the chain (just the opposite of Shimano's "Centeron" jockey
pulleys.)

The tension pulley is round.

I think that the friction of a well lubed derailer pulley, even a simple
bushing type one, is probably negligible, probably less than the
friction generated in the chain by the additional flexion of the
serpentine path the chain takes through a derailer.

These days most of my riding is on bikes without derailers, either fixed
gear, internal gear or both. When I do ride derailers it is with the
standard stock pulleys.

Quoted message said:

ie, would you recommend them if readily available. If not, why not?

If so, from where can they be acquired and for how much?

Too much trouble. These haven't been made since the 1950s. If you want
to play with adjustable ball-bearing pulleys, look for an old Schwinn
Varsity or the like with a Hurét rear derailer. Those also used quite
nice adjustable ball-bearing pulleys and they're a lot more common than
Beneluxes.

Sheldon "Mark VII" Brown
+--------------------------------------------------------------+
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| of the Orient... whose principal industries are...cheating, |
| which they are pleased to call..."commerce." These, also, |
| are the principal industries of the Orient. |
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+--------------------------------------------------------------+
Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
http://harriscyclery.com
Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

A lovable cartoon beagle barked:

Quoted message said:

Quoted message said:

I looked at a new SRAM derailleur at the LBS yesterday and alongside a
new Shimano derailleur and the upper guide pulley there was nowhere
near as much sideways movement in the former.

That's because it would violate a Shimano patent if it did have sideways
movement.

Quoted message said:

Quoted message said:

The question is if I stiffen up my derailleur to behave like a SRAM
derailleur, will I decrease the wear decrease the drivetrain noise and
improve the performance of my bicycle?

Not likely.

Sheldon "Not Bothered By Drivetrain Noise Since I Got My iPod" Brown
+-----------------------------------------------------+
| Once more upon the waters! yet once more! |
| And the waves bound beneath me as a steed |
| That knows his rider. Welcome to their roar! |
| Swift be their guidance, wheresoe'er it lead! |
| Though the strain'd mast should quiver as a reed, |
| And the rent canvas fluttering strew the gale, |
| Still must I on; for I am as a weed, |
| Flung from the rock, on Ocean's foam to sail |
| Where'er the surge may sweep, |
| the tempest's breath prevail. |
| --Lord Byron Child Harold's Pilgrimage |
+-----------------------------------------------------+
Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
http://harriscyclery.com
Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

whoa!!

"The reason the upper pulley has "float" is so the rear derailler has
less sensitivity to the cable tension being out of adjustment and
tolerates other wear/misalignment in the system."

no! my deore deray came with the upper pulley as the fixed width metal
bushing pulley-
therefore i thought that the upper part of the cage's width was fixed
by the metal bushing pulley

so that's wrong!

the fixed width metal bushing pulley goes on the cage bottom?

amazing.

Sheldon Brown said:

I blurted out:

Quoted message said:

Quoted message said:

Indeed, in my own first S.I.S. derailer, I replaced the stock pulleys
with a pair of nice ball-bearing ones that I cannibalized from an old
Benelux derailer, with no detectable degradation of shifting function.

Neil Brooks said:

Do they offer /better/ quality (or performance) than today's pulleys
(which always strike me as a low point in a high-quality drivetrain)?

I dunno. They do have nice adjustable ball bearings.

The jockey pulley has tall teeth like a sprocket, for tight lateral
control of the chain (just the opposite of Shimano's "Centeron" jockey
pulleys.)

The tension pulley is round.

I think that the friction of a well lubed derailer pulley, even a simple
bushing type one, is probably negligible, probably less than the
friction generated in the chain by the additional flexion of the
serpentine path the chain takes through a derailer.

These days most of my riding is on bikes without derailers, either fixed
gear, internal gear or both. When I do ride derailers it is with the
standard stock pulleys.

Quoted message said:

ie, would you recommend them if readily available. If not, why not?

If so, from where can they be acquired and for how much?

Too much trouble. These haven't been made since the 1950s. If you want
to play with adjustable ball-bearing pulleys, look for an old Schwinn
Varsity or the like with a Hurét rear derailer. Those also used quite
nice adjustable ball-bearing pulleys and they're a lot more common than
Beneluxes.

Thanks, Sheldon. Sounds to me as though I have a bit too much time on
my hands with this one.

To the tune of Warren Zevon, then. All together, shall we?

Leave my jockeys alone.
Leave my jockeys alone.

Sheldon Brown said:

A lovable cartoon beagle barked:

Quoted message said:

Quoted message said:

I looked at a new SRAM derailleur at the LBS yesterday and alongside a
new Shimano derailleur and the upper guide pulley there was nowhere
near as much sideways movement in the former.

That's because it would violate a Shimano patent if it did have sideways
movement.

Ahah, I didn't realise that a detail as simple as that could be
patented. You wouldn't know the patent number (possibly stamped on
the shimano derailleur itself, or maybe with the paperwork that comes
with each one) Sheldon?

I did a quick Google search using keywords 'patent' derailleur' and
'Shimano'. I didn't get the patent number I wanted, but I did find
this:

http://www.freepatentsonline.com/4267744.html

Not a Shimano patent but here is a quote from the 'background and
summary of invention section':

--------
"It is well known to those skilled in the art that, in the speed
change operation of a bicycle, it is desirable to make the drive chain
intentionally over-shifted to such a position slightly beyond the
position just under a sprocket wheel onto which the chain is to be
switched over. By over-shifting the chain in this way, the chain is
permitted to smoothly and quickly switched over onto a desired
sprocket wheel without disengagement from the free wheel assembly."

"Further, in case the drive chain is switched over from a smaller
sprocket wheel onto a larger one, it is desirable to return the chain
slightly back from the initial over-shifted position immediately,
because the chain is likely to undersirably come into contact with a
side wall of an adjacent larger sprocket wheel unless the chain is
returned back immediately from the initial over-shifted position."
-------

This March 5th 1979 patent then goes on to talk about a special lever
design (nothing to do with derailleurs themselves) designed to achieve
this. But if we ignore the rest of the content of the referenced
patent and go back to the two paragraphs I have just quoted, I think I
am getting close to an answer to my original question.

We all know that if we shove something in a particular direction it
tends to keep moving until some extenal force stops it (Newton's First
law). That means if we shove a guide pulley sideways and there is
extra side to side play in the guide wheel that allows it to slide
slightly beyond the position below the rear sprocket that you want to
engage, then it will do so. As soon as the chain engages on the next
sprocket it will be pulling at a very slight eccentric angle. The
chain will have a natural tendency to self correct as the rider's pull
the chain (and guide sprocket) directly back into line.

Thus the Shimano 'floating upper guide pulley design' neatly provides
the same benefits as the 'fancy gear selector' described in this
patent. How does that explanation sound?

SNOOPY

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Join the fight against aggressive, unrepentant
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Mike DeMicco said:

The reason the upper pulley has "float" is so the rear derailler has
less sensitivity to the cable tension being out of adjustment and
tolerates other wear/misalignment in the system. The floating pulley
automatically lines up with the cog above it. So if your cable tension
is a little off, or the derailler pivots wear a little, the floating
pulley accommodates some of the out of tolerance condition (i.e., slop)
in the system.

I'm not going to argue that the above is true, except for the first
bit where Mike suggests this is 'the reason' for the design. IMO this
is likely to be a side benefit of the design, not a reason.

I don't think you would 'design' something to work properly with
improper cable tension!

SNOOPY

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Join the fight against aggressive, unrepentant
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details

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Quoted message said:

whoa!!

"The reason the upper pulley has "float" is so the rear derailler has
less sensitivity to the cable tension being out of adjustment and
tolerates other wear/misalignment in the system."

no! my deore deray came with the upper pulley as the fixed width metal
bushing pulley-
therefore i thought that the upper part of the cage's width was fixed
by the metal bushing pulley

so that's wrong!

Yes and no.

Yes the upper guide pulley bushing is fixed.

But just because the upper guide pulley bearing is fixed, that doesn't
mean the upper guide pulley itself is fixed. The upper guide pulley
is able to move from side to side to a certain extent because it is
narrower than the fixed bearing it sits on.

SNOOPY

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Join the fight against aggressive, unrepentant
spammers 'china-netcom'. E-mail me for more
details

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Quoted message said:

i come to the idea that the wheels should be lubed with boat wheel
bearing grease frequently-try castrol at woolmort

Yes, I have taken to using marine quality grease on my own bicycle
where it is needed. Putting some of that between the pulley bushing
and the pulley itself is probably a good idea.

Quoted message said:

the lube frequency on a one to one level with the tooth wear you will
and forecast experiencing
both should come out equal over the pulley wheels life time.

I don't know about that. Those plastic pulley teeth are quite small,
there aren't many of them and they carry a lot of chain tension. I'm
not surprised the teeth on the lower tension pulley wear out, but *I*
don't think that means it is inevitable that the pulley/ pulley
bearing itself will wear out at the same rate. OMMV

Quoted message said:

betting the drive train out of line reduces the life span no problem

Yes but the Shimano system the available side to side play allows the
alignment to self correct to some extent.

Quoted message said:

bottom line- the pulley wheel needs maintenance but is like but more so
the other components ultimately disposable

Obviously if the pulley teeth wear down you are in trouble. But if
you have a (radially) sloppy bearing and it still turns, it will still
work, in my experience.

SNOOPY

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Join the fight against aggressive, unrepentant
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Snoopy *is n said:

Mike DeMicco said:

The reason the upper pulley has "float" is so the rear derailler has

Quoted message said:

Quoted message said:

less sensitivity to the cable tension being out of adjustment and
tolerates other wear/misalignment in the system. The floating pulley

Quoted message said:

Quoted message said:

automatically lines up with the cog above it. So if your cable

tension

Quoted message said:

Quoted message said:

is a little off, or the derailler pivots wear a little, the floating

Quoted message said:

Quoted message said:

pulley accommodates some of the out of tolerance condition (i.e.,

slop)

Quoted message said:

Quoted message said:

in the system.

I'm not going to argue that the above is true, except for the first
bit where Mike suggests this is 'the reason' for the design. IMO

this

Quoted message said:

is likely to be a side benefit of the design, not a reason.

This *is* the reason for the sideplay in the upper pulley. Shimano
calls it "Centeron", and it was a Major Technological Feature (to
borrow some advertising jargon) when Shimano introduced SIS back in
1986/7.

Jeff

te**yson@caverock.*et.*z said:

Ahah, I didn't realise that a detail as simple as that could be
patented. You wouldn't know the patent number (possibly stamped on
the shimano derailleur itself, or maybe with the paperwork that comes
with each one) Sheldon?

The US patent is 5,711,731.

Quoted message said:

I did a quick Google search using keywords 'patent' derailleur' and
'Shimano'.

I went to www.uspto.gov and searched for a patent with "pulley" in
the title and "Shimano" as the assignee. Came right up.

Dennis Ferguson

Sheldon Brown said:

These days most of my riding is on bikes without derailers, either fixed
gear, internal gear or both.

Both? You ride your ASC bike? I wish I had one.

--
Dave
dvt at psu dot edu