Hi Julien!
Yes, I am using 26x2.0in Schwalbe Dureme tires on my Nomad, equipped by Thorn with SKS P55 fenders (mudguards).
I've been very happy with the combination, enough to purchase a second pair of these mudguards so I could fit a rear fender to the front, allowing greater linear coverage and splash protection for me, the bike, and my panniers. I also purchased another pair of these mudguards to replace the rear one, which was fractured by my Extrawheel trailer hitting the lower stay mounting bolts when crossing from a logging road into a ditch and out again. I have not yet fitted it, but will this winter.
To aid you in your decision, I just went to the garage and measured everything.
The fenders are extruded, so the width varies slightly over their length. All of mine (front, rear, spares) measure 56.5-58.5mm wide depending on manufacturing tolerance and how they are fitted. They swell slightly wider where the stay brackets are riveted on. My tires' actual width varies slightly according to the pressure, from 47.5mm to 49.87mm; currently, they measure right at 48mm. This leaves the fender overhanging the tire by as much as 5mm on each side. The fenders are mounted to allow plenty of clearance over the tire, so this combination provides good coverage for the majority of my use.
On my 2014 European double-crossing, Forum member AndyBG kindly loaned me his Raven Tour. It was equipped with the SKS' P65 mudguards. These also worked well with 2.0in Schwalbe Marathon Deluxe tires, but covered the tires a bit more than needed in most cases, causing a bit more wind drag than I might have wished, but a loaded tourer with panniers is not so aerodynamic anyway -- it probably made no real difference to my speed. In heavy mud, the extra width was welcome and no detriment. Still, the wheels locked-up at times against the fenders when traversing rain-soaked dirt roads and the bike had to be rocked back and forth a bit to clear them. This would likely have happened with any tire-fender combination, given the conditions and sticky mud. I think it just took slightly longer to happen with the P65s. To give perspective, I myself sank to my shoe-tops in the mud when I got off to clear the tires.
However, there is another factor to consider: The P55s have a continuous, even width on the rear fender (except for manufacturing tolerances caused by the extrusion process and bending to fit). The P65s fitted to AndyBG's bike at the time had an opening cut out of the right side to allow chain clearance when fitted to a bike with derailleur drivetrain. This opening had the unfortunate effect of dumping mud and debris on the right chainstay and sometimes, the chain. Just something to keep in mind if you go with wider and wish to have full-width coverage -- check to see if the fender is cut away in this place. It can matter sometimes when fitted to a Rohloff-equipped bike where the chain does not need to move laterally when you shift, as with a derailleur drivetrain.
I'm working on a project bike now -- a used, lightweight MTB with derailleur drivetrain converted to a drop-handlebar "randonneur" intended for use at high speeds on gravel logging roads and intended to carry minimal loads. For it, I bought (also used, this is meant to be an inexpensive project) full-coverage Planet Bike Cascadia fenders. They measure 60mm and are intended to cover tires that will measure 50mm when inflated to my needs (Innova Swiftor, a kind of superwide near-slick). Again, the coverage will be about 5mm on each side of the tire. These fenders have no cutout in the sides, so I might have to make one to clear the derailleur chain once they are fitted. Unlike the SKS fenders, which are cellulose-plastic over an aluminum foil core and are a sort of brownish color in direct sunlight, the PlanetBike Cascadias are opaque black polycarbonate. So far, they have been as durable as the SKS' when used on my road bikes, but I am unsure how they will hold up on this project bike. Time will tell.
Much of a fender's effectiveness depends on the vertical clearance between it and the tire. Too close and you risk jamming the fender with debris like wet leaves. Too much, and some water can escape. I have my Nomad fenders set generously high and a little added clearance at the bottom-rear of each to better catch thrown water.
This is probably more information than you needed, but hopefully helpful if you are looking at all options.
Yes, I am pleased with the combination of P55 SKS fenders used with 2in Schwalbe Dureme tires on my Nomad.
All the best,
Dan.
