What about the front Mick? What are ya running there?
The 120/90-18 is way too big. It is both higher and wider than the 120/80-18. I fit one in with great difficulty when i needed it in the late fall and none of the local suppliers had the /80. Never again.
I have considered trying the /100 on the front but why bother?! Oversize tires in my experience are way to much hassel for no significant gain.
i swear by Metzeler ME880 Marathons. Stick to the curves like glue - I ride hard in the twisties and scrape the pegs every now and then. And they are very good in the wet.
Plus they last well. I got 10,000 miles out of the rear, most of that loaded up with heavy saddlebags, camping equipment etc.
In theory there is no difference between theory and practice. In practice there is.