Different rear cassettes?
I found a wheel that fits the beater I'm putting together for a mate to use. It's a 27 inch wheel but has aluminium (looks like) rims, and more annoyingly a 5 speed sprocket that looks more like a cassette than the screw on I was expecting. It's splined in the centre the splines go all the way through the cogs, but the spline diameter is too big for my shimano tool to fit in, its about a mm too small for my bottom bracket tool to go in! Anyone know from my rubbish description what this is and where I can get a removal tool? Or am I just being a dunce and it is a screw on of some sort? It doesn't make sense to me, I'm used to 2 or 4 pin screw on, or a regular shimano cassette with a screw in disc at the end!!
Stumped