I have recently put a Shinko 757 150/80/17 on the front and am lovingit, it sticks like sh#t to a blanket, a bonus was that it was 2/3 of the price of a metz have 1500km's on it with no noticable sign of wear. I went up to a swap meet which means going up the Clyde Mt unbeleiveable feed back, on the return trip it was bloody hot and I was pushing it a bit when I got home I was expecting it to be a bit chewed up but no it looks fine and seemed to cope well with the extra heat.
There is a Bridgestone R852 240/55/16 which having 55 profile will give a better ground clearance and help correct the speedo, if when I wear out the Darkside which I am more than happy with! I might add, I decide to give a another bike tyre a go it will be either a Cobra or a Bridgestone because the metzlers are not a Radial which the other two are and is the reason why I think don't get the same handling the Cobras are giving and why we have been getting sh#t wear out of them. If Metzler had been seriuos about development of a tyre for the Rocket they might of started with a clean sheet of paper and designed a Radial as the Marathon Cross Ply has been around 20+ odd years