7sp cogs loose on pins?
 

I have a 7sp Shimano freehub where the cogs are in a 5-cog set that is pinned together with a 2-cog cluster on top of them that is held in by a lock-ring. I just noticed that the 5-cog pinned assembly has play. The cogs wobble around relative to each other. There's slop. The freehub looks fine. The cogset looks fine. Are they supposed to function somewhat loosely? Hard to believe. I see no damage. If I push down on the 4th 5th or 6th cogs they will all compress the bigger cogs under them and hold them snug. If I push down on the 3rd cog, the smallest cog in the assembly, the other cogs stay loose. The 2 outer cogs are presently compressing the 3rd cog. Everything fits snugly. But the 3rd won't snug up against the bigger ones under it. Hmmm...

i've never seen a cassette that is designed to have play in it. i suspect that either there is a spacer that should be added before the cassette is installed on the freehub, and the cassette may be a thin shim that is supposed to be added between the two-piece cog set and the five piece set. it could be the cause of the small gap.

It sounds like the lockring is not clamping the cassette correctly. Does the cassette overhang the freehub body sufficiently that the lockring bottoms on the cassette rather than on the freehub? If you have a 7 speed cassette on an 8-9-10 speed freehub you need a 4.5mm spacer behind the cassette, but you still need to verify a 2-3mm overhang; some hubs need an additional spacer besides the 4.5mm one. This thin spacer is also needed for 8-9-10 speed cassettes.

The pins/rivets/screws which hold the cogs together are just for ease in shipping and installation, they are not required to keep the cogs together and can be removed or ignored; I grind the heads flush routinely. The cogs bear upon the freehub splines which keep them from rotating; the pins are not needed for this.

There re two opposing schools of thought about whether the screws or rivets that hold most of the cogs together on Shimano and other brands of cassettes are necessary. Some people say that the screws are not necessary, and are only there to make assembly easier/faster at the time of assembly. Other people say that the the screws hold the cogs and spacers together to spread out the torque being transmitted from the driven cog over all of the cogs and soacers that are held together helping to prevent damage to the freehub body. Freehub bodies that are made from alloy will definitely be damaged by loose cogs, with notches being cut in the freehub body. Steel freehub bodies resist being damaged more than the alloy freehub bodies.

Personally, I agree with the cogs being attached as a way to prevent damage, and I've tossed Shimano cassettes that were riveted together when they became loose in the past. I should have kept them and salvaged the spacers, as I see people actively looking for the spacers. If you have a cassette that is screwed together, you may be able to tighten the screws to take the sloppiness out of the assembly. If you have a riveted cassette, you may be able to tighten up the rivets Otherwise, I would retire and keep for salvage any riveted cassette that I could not tighten up.

If you have any cassettes that are screwed together, you can replace individual cogs if they wear out with a cog from a riveted cassette that you've retired if you wear out any cogs. I've never worn out a cassette, but I've been told that if you do, it's usually only one or two cogs that need replacement, not the whole set of cogs.

Screwing on Last Cog should tighten up older cassettes, or the lock ring on the newer ones. add a shim spacer if it's not so..

Thanks! I will dive deeper into the world of spacers...

Is the lock ring snugged to 30 FT-LBS?

If that doesn't compress things I would remove the cassette.
IF it uses screws, tighten them.
IF it uses rivets, either remove them or see if compressing the "stack" in a vise will tighten up the gap.

Did you do a cassette change?
11T lock rings are slightly different than the larger sizes. IF the smallest cog was changed........

the pins are just there to speed the factory assembly , they can be left out.. + my being then loose cogs, are a source of custom chosen combinations potentially..

7 speed cassettes are well before the 11t high gear of current designs with 10 cogs.