bearings vs bushings: RD jockey wheels

[AngryScientist]

because they are inexpensive, and seem to work well, i have Centaur RD's on a few bikes. i was giving my gravel bike a thorough cleaning last night and took a look at the jockey wheels and gave the bottom one a spin without the chain on it, and oof, gritty as hell.

pulled the RD apart and was surprised that the campy jockey wheels dont use bearings, but use bushings, which took some "convincing" to come apart. i would have guessed there were bearings back there, but nope.

anyway, this is probably fine for road, but i think for a gravel bike that sees a lot of wet, silty gritty conditions, bushings are non-ideal. the inside surfaces of the wheels are pretty scored, so i think these are toast.

time for an upgrade!

[Mark McM]

Derailleur pulleys have used bushings since the derailleur was first invented, and even today most derailleurs use bushings. Bushings are cheaper, and generally last longer than ball bearings in this application. Sure, bushings slowly grind down over time, but bushings have more contact area and grind down slower than ball bearings, which can go south in a hurry in gritty conditions.

In my experience, bushings continue to turn after plastic pulley teeth are worn down, whereas ball bearings frequently fail before the plastic pulley teeth are gone. Ball bearings can save Watts (which is why I use them), but they have to be replaced more often.

[AngryScientist]

Originally Posted by Mark McM

Derailleur pulleys have used bushings since the derailleur was first invented, and even today most derailleurs use bushings. Bushings are cheaper, and generally last longer than ball bearings in this application. Sure, bushings slowly grind down over time, but bushings have more contact area and grind down slower than ball bearings, which can go south in a hurry in gritty conditions.

In my experience, bushings continue to turn after plastic pulley teeth are worn down, whereas ball bearings frequently fail before the plastic pulley teeth are gone. Ball bearings can save Watts (which is why I use them), but they have to be replaced more often.

i concur for this small bore size, bearings may be challenged. going to see what's available in a well sealed bearing wheel.

which ones do you use Mark?

[ColonelJLloyd]

I have found these to be great and I can't imagine anything cheaper.

[AngryScientist]

Originally Posted by ColonelJLloyd

I have found these to be great and I can't imagine anything cheaper.

yes. i actually have a set of the grand cru ones in another RD operating successfully for mucho miles. they are 10-toothers though. not that i've found that to matter either.

[dave thompson]

Originally Posted by ColonelJLloyd

I have found these to be great and I can't imagine anything cheaper.

I’ve run these TACX pulleys on all of our bikes for many years. They’re tough, very durable and have remained trouble-free forever.

[oldpotatoe]

Originally Posted by AngryScientist

i concur for this small bore size, bearings may be challenged. going to see what's available in a well sealed bearing wheel.

which ones do you use Mark?

Not Mark but Tacx are good, cart bearing, ones. BUT grease in those steel insert and brass bushing work really well...Ceramic bushings do too is you keep them lubed well. Seen more than a few ceramic insert/bushing just be a wee pile of ceramic 'dust'...

they are 10-toothers though. not that i've found that to matter either.

Tacx makes 11t ones..11t ones may not fit onto otherwise 10s rear ders..10t will work fine on 11s ones but ya ought just match the original number of 'teeth'...it 'may' have an effect on chain length..That's how early gen DA 'long cage' rear ders got that way..short cage, BIG pulleys.

[weiwentg]

Originally Posted by Mark McM

Derailleur pulleys have used bushings since the derailleur was first invented, and even today most derailleurs use bushings. Bushings are cheaper, and generally last longer than ball bearings in this application. Sure, bushings slowly grind down over time, but bushings have more contact area and grind down slower than ball bearings, which can go south in a hurry in gritty conditions.

In my experience, bushings continue to turn after plastic pulley teeth are worn down, whereas ball bearings frequently fail before the plastic pulley teeth are gone. Ball bearings can save Watts (which is why I use them), but they have to be replaced more often.

Speaking of that, Ceramic Speed has a pulley friction test up on its site. It seems like you could save half a watt going from Shimano 105 (2 bushings) to Ultegra (1 bushing, 1 bearing), and then another half a watt going from there to Dura Ace (2 bearings).

I wasn't aware of the longevity differences between bushings and bearings, though.

[AngryScientist]

closing the loop. installed some Hope wheels. i figure Hope knows a thing or two about playing in the dirt.

plus....purple.

[Davist]

Bushings are much better... I used the cartridge bearing version (bullseye? ringle? can't remember who made them, but they were purple) in the 90s on my mountain bike, they seized in a muddy/gritty race (I thought/assumed they would last forever) and tore off my rear derailleur. It was a 30 mile single loop so I had to walk/push about 10 miles since I didn't have a chain tool. Never again. edit and ps: the top pulley needs a little "float" to center itself (well, at least it used to) and that also leads to bushings being a better choice

[AngryScientist]

good reminder. i'll keep an eye on them to see if they get gritty and hopefully catch before seizure !

on the bike now. shifting seems the same, though this is on a friction shift set-up.

[Bob Ross]

Originally Posted by AngryScientist

i figure Hope knows a thing or two about playing in the dirt.

I still don't get why any jockey wheel needs holes in it. I guess those look slightly less likely to clog with gunk than the Campy, but still...

The purple is hawt though.

[Steve in SLO]

Angry,
On my cyclocross/gravel bikes my jockey wheels have looked like yours or worse every time I get around to maintaining them-lots of grit in and out. A toothbrush, some mineral spirits and running a cloth through the bores of bushings and wheels, reassemble with medium waterproof grease (I like Bell Ray blue motorcycle grease) will make them spin smoothly between your fingers. Back on the bike they feel good.
Do I lose maybe a 10th of a watt? Maybe.
Is my wallet heavier? Definitely.

[zzy]

Originally Posted by Bob Ross

I still don't get why any jockey wheel needs holes in it.

speed holes, they make the bike go faster

[AngryScientist]

Originally Posted by Steve in SLO

Angry,
On my cyclocross/gravel bikes my jockey wheels have looked like yours or worse every time I get around to maintaining them-lots of grit in and out. A toothbrush, some mineral spirits and running a cloth through the bores of bushings and wheels, reassemble with medium waterproof grease (I like Bell Ray blue motorcycle grease) will make them spin smoothly between your fingers. Back on the bike they feel good.
Do I lose maybe a 10th of a watt? Maybe.
Is my wallet heavier? Definitely.

you're exactly right steve, i could definitely have re-habbed these looking at them closer this morning and probably will still do so and throw them in the parts drawer for next go-around. still though, purple is cool