I take it then that the 130/90-17 rear fitted. Thats the only one they sell in that size. I would email them but most of these places havent a clue at what they are talking about.
the terrain is from what i can see from the photos is rocky paths, with some river crossing, mud, grass etc etc Mostly the same stuff you's guys do but up in mid wales. Havent booked it as of yet but hoping the dates we are planning on going are still avaiable. (easter sometime will post dates later when confirmed with me dad the boss)
I have heard mixed stories about the TKC80's but most say they do off roading but not great but can take road mileage ok. as for the mt21's they look more like a motocross tyres and as you say they dont like lots of road riding. Both have there goods and bads.
The other opposion is change my front road tyre to an off road tyre before i leave, and take my off road tyre with me on back of bike. Once i get to the place change it over, do the off roading, then change back again for road riding home. But this causes problems with time, changin tyres when not at home, bring loads of tools, etc etc.
Would the pirellis take that amount of road riding at that speed or would it be more sense to buy the pirellis (being the better looking off road tyre) and change the rear down there??