Neil -- BMW originally fitted Enduro 4s or Michelin T66s to the 1100GS and Metzeler subsequently developed the Tourance to meet the demand for a "sticky" or softer compound tyre from riders ; particularly in Germany and France , who rode alongside supersports / race rep riding mates on the road , or did a lot of track days . The wear rate from Tourances is approx. 2,000 miles less as compared to Enduro 4s IF THEY ARE USED AS DESIGNED - i.e at the same temperature as you would run something like a BT010 . In other words , if you do not warm them up before you go for it they will not operate properly and consequently they will slide . You therefore have to make an honest assessment of what you want from your tyres , where you will be using them and how you ride . In a perfect world and given an in-house tyre fitter waiting just for me I'd opt for , - TCK80s offroad , T66s for a mixture of dry tarmac and some offroad , Enduro 4s for the road work in freezing conditions and Tourances for warm spring/summer/autumn tarmac and track days . Both Metz. tyres are worlds better on wet tarmac than the T66s but both the Tourance and ; to a lesser extent , the "4" have markedly less off road capacity than the T66s .You pays your money and ..... Whatever you opt for it is my experience that both my bike and my tyres are WAY better than my ability , courage etc. !