The higher profile of a 150/70x18 will raise the back a little, which in itself isn't a bad thing on the MC18, as the standard ride height is a bit slow. Lifting the rear will quicken the steering very slightly.
The width is obviously fine, but a 70 series tyre may look a little bulbous. If there is nothing else available though, there isn't much you can do. I'm looking for a nice 150/60x18 for my MC16 project at the moment, so I understand your problem.
I do have a 17" wheel for mine though, and a different swingarm, shock and linkage to accommodate it and raise the rear. I will probably end up using the 17" wheel.
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Andy.
NSR-WORLD.COM
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