I erroneously tagged those as Belleville, which is incorrect. Please pardon my error.

"Wave" washers is more appropriate as Bellevilles are 'cone' shaped.

Heh... I always thought it was a Bike Forums site policy. Same with the List Which Shall Not Be Named. About which I am almost certainly wrong as well.

And, man... maybe I shouldn't have put that NIB 1st-gen Superbe on the Fuji back in 2021...

--Shannon

well, they aren't wave washers either. They are just shims. SunTour seemed fond of them for some reason. They take up a small amount of space, and maybe(??) provide some protection from wear for the aluminum.

In their freewheels, it seems like they select how many shims to use individually in order to get the desired clearance in the bearings. With the derailleurs, some days I think they did the same, but that's just casual observation and not a detailed review of a number of them. It does make me worry about used derailleurs that might be missing a shim. Hasn't been a problem yet, though!

Steve in Peoria

I can accept that!

Once used, the thinner selections will distort a little bit once allowed to move freely again, they can look 'warped' rather than flat.

Even if not present for spatial adjustments, having one in between two moving parts adds two more surfaces that hold lube, reducing wear.

yep, they are thin enough that a bit of mishandling can bend them, so some might end up looking wavy.
Also, they are thin and easy to lose, so some used derailleurs might not have the right fit or performance.

I've always applied a coating of grease to the shims, just to help things slide along. Or was it to attract more dirt and crud?? Hard to be sure.

Steve in Peoria

Shift a Campy Nuovo Record rear derailleur and it goes "Duhhh.... OK ...if you really want me to"...".
Shift a Suntour Cyclond MkII rear derailleur and in the right gear already, way before you even stop moving the lever!
That's how the two deraillers shifted on my Peugeot PSV, in the mid 80's.

I'm a big fan of SunTour Cyclone GT RDs, already had a couple of mk2s then my latest project really needed 37 chain wrap.
So I got my first Cyclone GT mk1, and I really like it.

Mk2 possibly works slightly better, but almost impossible to tell, they're both great.
Which one looks best is a toss up - i always polish the printed logo off the mk2 so it's just shiny and very very small.

There's a mk1 GT on Ebay UK for £35 atm.