kevmk81

So, the wheel I am pointing to, how tight does one need to torque these typically? I noticed if I tighten it till I can't tighten anymore the wheel doesn't spin freely without force. If I loosen it just a bit off of fully tightened, it spins freely.

Anyone know? Seems like if it's too tight it would take some energy just to do that let alone put any power out. Granted not much energy, but it all makes a difference!

fstshrk

The upper jockey wheel should not only spin freely but should have play on the z-axis so that it can adjust during the shift range. I have never seen one work itself loose.

hamster

It has to be tightened all the way. If it does not spin when fully tightened, take out the wheel, clean and lubricate all internal surfaces with an appropriate type of grease. Do you see light metal caps on both sides of the wheel? It could be that your wheel is seized inside due to excess dirt/grime and it can only spin together with caps. When you tighten it all the way, caps are pressed against the cage of the RD and it can't spin at all.

Some friction is to be expected. As I recall (I may be misremembering), most RDs use bearing-less pulleys here because there's a need for the jockey wheel to float sideways slightly, and that is hard to implement with ball bearings. The downside is unavoidable mild friction. High-end Shimano RDs (Dura Ace, XTR) have sealed bearing cartridges which eliminate friction but cost an arm and a leg.

fstshrk

Both Ultegra, XTR and SRAM use a sealed bearing for the RD pulleys. It is not that hard to get side to side float with a sealed bearing. The whole bearing floats on the axle.

NWS Alpine

You can read the manual for your specific part and get the proper torque value. Too much torque and you will degrade your shifting and cause premature failure. Shimano is usually around 22-44 in lbs of torque. So not much torque.

hamster

Take a look at exploded views of Shimano's Di2 RDs.

Ultegra (6700), Ultegra Di2 (6770), Ultegra Di2 (6870): Elongated cylindrical bushings plainly visible in both pulleys (just to the right of each pulley wheel)
Dura Ace 7900, Dura Ace Di2 1st gen (7970): Only one bushing. Top pulley has a sealing bearing cartridge.
Dura Ace 9000, Dura Ace Di2 2nd gen (9070): Sealing bearings in both pulleys.

Yes, Shimano specifies 22-44 in lbs. However, it is very hard to tighten a bolt to 44 in lbs with a handheld allen key. With a long torque wrench, easy. With a flimsy 2" long allen key, no way.

P.S. Take the longest allen key you can find (pulleys are held by 3 mm bolts, so, it's going to be a pretty small key.) Turn the bike upside down. Insert the key into the bolt so that its handle is horizontal. Grab the tip of the handle and pull it upwards hard enough to lift the entire bike off the ground. That's 22-44 in-lbs of torque (give or take).

NWS Alpine

Ugh it's inch-pounds not foot-pounds. To put it into perspective lets say 30 in-lbs is about 3.3 nm. Stem bolts for carbon bars are even higher than that.