I have a Sunrace 11 speed , 11-50 T Sunrace Cassette on a Shimano hub,
I detected some movement when I held the 50T in my fingers and lifted it up and down , it moved about 1mm , so I took it it off cleaned up and refitted it, all tightened to the max , the sprockets are tight together and yet there is still a bit of play , is that ok or do I need to change the spacer at the hub , it’s just under 2mm or could it be something else ?
It is indexing ok , maybe I’m being a bit overly concerned,
Cheers

is the play in the cassette [rattly/loose]or the freewheel[ whole casette moves as one not just individual rings] ?

Either way there should be none - how much you are willing to tolerate is your choice but something is not as it should be
the later i could live with some play[ till i fixed it ] the former i would not ride.

Your auto correct or typo of fingers needs urgently to be corrected !

There is no rattling, all the sprockets are as should be , I am wondering if this Sunrace cassettte is not a good fit , Think I’ll try putting the original 42 T back on an see if I’m correct ,

And yep, auto correct could start something big !

if just the biggest one is it a seperate cog and missing a spacer?

I would be making sure it's not the bearings in the freehub as Lazarus says. It won't be as obvious without the cassette on since the large diameter magnifies the play - but that could be why you've noticed now with a bigger diameter sprocket on it.

I’ve had it all in bits again , bearings have been regressed and set now , , the Sunrace sprockets are not fitting the Shimano splined hub to well , even after cranking it up to 40 nn , I’m pretty sure that is why it’s got a bit of movement , I’m not to sure if I can fix this , I’m going to put a few miles on and then check it again , and as said the small prob less than 1mm play at that point it is being magnified by the time the 50t is fitted ,

If you can wiggle the cassette rings slightly side to side then it sounds like you may need a slightly thicker spacer. I have had this issue in the recent past with a Sunrace cassette on my freehub.

It’s got a 1.85 spacer at the mo, I’ll have a look round for a 2mm one
Cheers