On my 1st set and cant get my cassette tool on to tighten the cassette lockring on as the qr axle is too thick. Do I need to remove this? And if so does it pop out like the fronts? Or do i need to change my cassette tool? Thanks.

It would be better to get a cassette tool that fits over the axle – mine does and its just a cheapie.

But for the meantime I see no reason why you can't take the end cap off to do up the casette – the only issue is the freehub could fall off while you do it.

Is it a sram/shimano cassette? I've got the same problem with one of my hubs – only one mind, the shimano tool won't fit, but the Park one will. The Park Tool remover has a thinner body. Can you borrow one? Or ask to try (then buy) suitable at your lbs?

I don't think that you will be able to get the end cap back on after you have screwed the lock ring on will you?

Good shout folks, sounds like it could be another tool for the box! I'll try the 'try before I buy method from the lbs'. Always good to support them. Just wanted to be sure before I open the hubs up.

Check your cassette tool first and see if the middle bit that sits in the axle is removable or not. I had this issue and simply pulled the locator bit out of my tool and it now sits on perfectly.