And so,
the bearing inner and outer races from the pulley of a RED 10-speed rear derailleur and
the rear derailleur pulley from a Rival 1 remained.
This is the final result. Rewinding the timeline,
my watch mentor came by today on a cyclocross bike, and
apparently something was off with the rear derailleur pulley on his
front-single-speed Rival 1 setup.
Relative to the fixed pulley bolt and the bearing's inner race,
all the parts on the outside were rattling side to side,
and there was play even in the eccentric movement.
It was bad on both the upper and lower pulleys, but especially the lower one.
That's the pulley in the image above, but
the bearing retainer had cracked, and
the broken retainer was being pulverized into fine pieces during rotation,
destroying the bearing through wear.
There must have been a decent period where the feel was obviously off before it got this bad, but...
The ball bearings were darkened and discolored,
and the raceways were riddled with spalling.
The rubber seal was also worn away except for the metal core,
so it couldn't snap snugly onto the outer race anymore.
The next Kansai Cyclo race at Makino is next Sunday.
We need to replace the pulley before then, but
it doesn't look like we'll make it in time.
So I measured the bearing size and
found it to be 6mm inner diameter, 19mm outer diameter, 6mm thick.
This is a standard size bearing,
equivalent to a miniature bearing 626.
The pulley section is 12T, and even-tooth pulleys can sometimes experience
uneven wear where the teeth wear alternately, which would be theoretically undesirable,
but this pulley has a narrow-wide tooth profile
so the design always has even teeth.
↑This is an 11T pulley that was on my own RED 10-speed rear derailleur,
an early-model type with weight-relief holes that go through completely,
from a period when pulley cracking happened frequently.
This one's actually already cracked too.
↑This is a later-model pulley with half-depth weight-relief holes.
They quietly changed the specs, but it's clearly a crack-prevention measure,
and there are basically no cracking incidents with this pulley design.
The marking on the seal reads S626CE-2RS,
where 626 is the bearing size—the same as the Rival 1 bearing.
CE means ceramic hybrid bearing, and 2RS means dual-side rubber seals.
Now, with this bearing,
seeing as the pulley was cracked,
I was able to remove it by hand.
The relationship between this pulley and bearing
had a form where the press-in direction was fixed,
but the Rival 1 pulley didn't seem to have that constraint—
it looked like it could be pressed either way, so
on first try, I figured out a jig and method for bearing replacement.
Nailed it.
The image above shows it partially removed and out of the jig.
↑From the other side it looks like this
I removed the outer race.
Sure enough, the inner diameter, outer diameter, and thickness all matched.
I transplanted the bearing.
The image above shows it mid-press, and
I then pressed it all the way to the proper position.
↑For RED 10-speed
↑For Rival 1
The pulley bolt diameter and length are different, but
the round plate pressing on the bearing has a step that only grips the inner race
and a flange that fits into the 6mm hole,
and the open hole size differs to match the pulley bolt—
the bearing size is actually common between them.
The bearing dimensions are in metric,
and the bolt threads are also metric (M3 or M4), but
when I measured the diameter of the pulley bolt section where the threads aren't cut
(the part just below the bearing)
it appears to be an inch diameter.
The Rival 1 rear derailleur's upper pulley also has obvious play requiring replacement,
just a bit less severe than the lower one, so I'll replace it later.
I've already ordered the parts to get them in time for Makino.
Also, after this incident, I've made it a point to stock 626 dual-side rubber seal bearings,
so I can handle the same situation immediately if it comes up again.
the bearing inner and outer races from the pulley of a RED 10-speed rear derailleur and
the rear derailleur pulley from a Rival 1 remained.
This is the final result. Rewinding the timeline,
my watch mentor came by today on a cyclocross bike, and
apparently something was off with the rear derailleur pulley on his
front-single-speed Rival 1 setup.
Relative to the fixed pulley bolt and the bearing's inner race,
all the parts on the outside were rattling side to side,
and there was play even in the eccentric movement.
It was bad on both the upper and lower pulleys, but especially the lower one.
That's the pulley in the image above, but
the bearing retainer had cracked, and
the broken retainer was being pulverized into fine pieces during rotation,
destroying the bearing through wear.
There must have been a decent period where the feel was obviously off before it got this bad, but...
The ball bearings were darkened and discolored,
and the raceways were riddled with spalling.
The rubber seal was also worn away except for the metal core,
so it couldn't snap snugly onto the outer race anymore.
The next Kansai Cyclo race at Makino is next Sunday.
We need to replace the pulley before then, but
it doesn't look like we'll make it in time.
So I measured the bearing size and
found it to be 6mm inner diameter, 19mm outer diameter, 6mm thick.
This is a standard size bearing,
equivalent to a miniature bearing 626.
The pulley section is 12T, and even-tooth pulleys can sometimes experience
uneven wear where the teeth wear alternately, which would be theoretically undesirable,
but this pulley has a narrow-wide tooth profile
so the design always has even teeth.
↑This is an 11T pulley that was on my own RED 10-speed rear derailleur,
an early-model type with weight-relief holes that go through completely,
from a period when pulley cracking happened frequently.
This one's actually already cracked too.
↑This is a later-model pulley with half-depth weight-relief holes.
They quietly changed the specs, but it's clearly a crack-prevention measure,
and there are basically no cracking incidents with this pulley design.
The marking on the seal reads S626CE-2RS,
where 626 is the bearing size—the same as the Rival 1 bearing.
CE means ceramic hybrid bearing, and 2RS means dual-side rubber seals.
Now, with this bearing,
seeing as the pulley was cracked,
I was able to remove it by hand.
The relationship between this pulley and bearing
had a form where the press-in direction was fixed,
but the Rival 1 pulley didn't seem to have that constraint—
it looked like it could be pressed either way, so
on first try, I figured out a jig and method for bearing replacement.
Nailed it.
The image above shows it partially removed and out of the jig.
↑From the other side it looks like this
I removed the outer race.
Sure enough, the inner diameter, outer diameter, and thickness all matched.
I transplanted the bearing.
The image above shows it mid-press, and
I then pressed it all the way to the proper position.
↑For RED 10-speed
↑For Rival 1
The pulley bolt diameter and length are different, but
the round plate pressing on the bearing has a step that only grips the inner race
and a flange that fits into the 6mm hole,
and the open hole size differs to match the pulley bolt—
the bearing size is actually common between them.
The bearing dimensions are in metric,
and the bolt threads are also metric (M3 or M4), but
when I measured the diameter of the pulley bolt section where the threads aren't cut
(the part just below the bearing)
it appears to be an inch diameter.
The Rival 1 rear derailleur's upper pulley also has obvious play requiring replacement,
just a bit less severe than the lower one, so I'll replace it later.
I've already ordered the parts to get them in time for Makino.
Also, after this incident, I've made it a point to stock 626 dual-side rubber seal bearings,
so I can handle the same situation immediately if it comes up again.