Originally Posted by
icemilkcoffee
The single wide spline is there to help clock all the cogs correctly. This feature is only needed when you have loose cogs in your cassette. It is not needed when you have a monobloc cassette.
Ahh! Thanks for explaining this. In all my years of cycling, this is the first time I've had a monoblock cassette and I never knew this. Just goes to show how important forums like this can be.