Yesterday I swapped my Schwalbe Marathon Supremes (26x1.6) for Marathon XRs (26x2.0) and what a difference, it felt like I was towing a trailer. The Supremes roll so well I think I lost 2kph on my 29km commute to work today.
The Marathon XR is/was the flagship expedition touring tyre form Schwalbe and is bloody heavy at 790g. It rolls OK but acceleration is very very bad. I do like the larger volume of the 2.0" tyre though, nice and cushy, I think I will go wth 2.0" Supremes when the 1.6"s wear out.
I will be using the XRs on the first stage or our trip from Perth to Busselton via the Munda Biddi Trail which will be mostly off road so I wanted a bit more tread. I will be putting the Supremes back on as soon as we get to Busso :)
I might be bagging these tyres but if I was planning on riding across lots of dirt (or just crap) roads then these are what I'd use.