RoMad

I was changing my wife’s rear tire and noticed that her jockey wheels bearings are really bad. I searched online and found out there are two different size 105 11 speed derailleurs. I measured center to center on her jockey wheels and it’s 3 1/2”
many suggestions on which wheels I need and where to get them.

roadcrankr

Use 5800 pulley sets - available online all day long for around fifteen bucks.

dabac

…. I’ve only ever counted the number of teeth, which seems to have worked fine…

jimc101

That should have bushing, not bearing, you maybe able to get away with just stripping, cleaning and re-greasing them, rather than replace.

The pulley wheels (the name you need to look for if looking for Shimano replacement parts) don't look worn, as they will normally get very shark toothed when really worn, just very dirty.

For the sizing of the RD, for Shimano, they make 2 sizes of RD for road, Short & Med , the only difference if looking at 2 from the same range, as in 5800 will be the cage length, nothing else.

You can se the difference by looking at the EV for the part, for example the 5800 RD EV-RD-5800-3712C.xls (shimano.com)

WizardOfBoz

They looked a little worn to me (the tooth faces are parallel, not wedge-shaped, the the grooves between the teeth are pretty deep). But that may be normal and you may be spot on. I defer to your judgement on this.

I'm a big fan of cleaning and lubricating stuff to make it work again, but then again, jockey wheels should be replaced every 500,000 road miles (or 100 years, whichever comes first) whether they need it our not.

dedhed

Cage length doesn't matter, pulley wheels are the same for both.
But as said those look good, clean and lube them up.

sovende

Yup, a good “fluff & buff” should do the trick! I generally completely disassemble the pulley/cage portion of the derailer (or derailleur, if you please ) in order to remove any rust and/or accumulated grime from the components. As mentioned, the bushing is the bearing. I make sure that both the inner and outer surfaces of the bushing are clean and smooth. The same goes for the unthreaded portion of the shoulder bolt (pulley axle) that secures the outer and inner cage plates. The hub plates on both sides of each pulley also should to be clean and rust free. Much of the above might be considered “overkill” as friction-free isn’t absolutely necessary. The pulleys just need to be able to turn .

dedhed

More importantly the upper needs to have the side to side float for proper indexing.

sovende

Good call! I’m guessing that the design engineers take the need for the “side to side float” into consideration when selecting the dimensions of the components, specifically the pulleys themselves and the shoulder bolt axles. On the outside chance that assemblies of this nature may have differences in dimensions for the components (perhaps not in this case), I most often keep the components of an assembly separated while cleaning them and reassemble back to original configuration.

dedhed

I believe the bushing is longer on the "centeron" guide pulley to allow the float.

sovende

I''m making a mental note to check that out the next time I work on a derailer!

smd4

That would make the cage wider at the top--the cages wouldn't be parallel. The bushings should be the same size. The centeron pulley has the float built in. Same goes for the pulley bolts--they are the same length. The bolts tighten against the bushing, which doesn't move. The pully wheel revolves around the stationary bushing.

dedhed

I should have said wider than the pulley to allow for the float. Either way you have to make sure the upper pulley has side float for proper indexing

SoSmellyAir

The two sizes (SS and GS) of 11s 105 RD differ by parallelogram geometry and cage length, but use the same pulleys.

For a few more bucks just upgrade to Ultegra pulleys, both of which use bearings, rather than the one bearing and one bushing of the 105 pulley set.

Shimano Ultegra 11 Speed Road Pulley Wheel Kit | Competitive Cyclist