First a summary of my opinion regarding the Schwalbe Marathon Plus tires...heavy, hard and slow. It's worth it to me to have an extra flat or two by using other lighter and more supple tires.
Now that I have an e-trike I've been using Schwalbe Marathon Plus tires. At least up until now but no longer. Yes I've had fewer flats but I've still had flats. Two flats so far. Both punctures towards the sidewall where there is less protection. Fewer flats is nice but repairing a flat while on the road can be tough. These brutes are NOT supple by any means. The front tire requires three tire levers to coax it off the rim and back on. The rear tire requires two levers. After the second flat I went back to using lighter and faster tires from my pre e-trike days.
Schwalbe Marathon Plus 35/406 (20"x 1.35")
Schwalbe Marathon Plus 40/559 (26"x 1.5")
I'm now using folding 35/406 Schwalbe Kojaks up front and a folding 42/559 Schwalbe Marathon Supreme on the back (I wish Schwalbe still made the 406 Supreme again). The Kojaks are fine for now but I want to find a 406 tire that is more puncture resistant but not to heavy and easy to remove from the rim when I get a flat while on the road. (As of Sept 3rd I now have a pair Continental Contact E25 37/406 on the front and I'll see how that works out. Although they do seem a little slower then the Kojaks but still faster than the Pluses. But they have a better puncture rating than the Kojaks.)
Schwalbe Marathon Supreme 42/559 (26"x 1.60")
Schwalbe Kojak 35/406 (20"x 1.35")
Regardless of which tires I use, when possible I like skinner tires on the front for handling and a little wider tire on the rear because of the extra weight on the rear tire and for comfort. I've also found that with the wider tire on the back that the rear is more stable in tight turns.
I have found that the only benefit using the Plus tires is fewer flats. Fewer flats not "no" flats. Right now I'm of the opinion that fixing an extra flat or two is better than having to be pedaling with all the extra rolling weight of the Plus tires. The total weight of the Plus tires is 1,990g (4.36lbs) vs 900g (1.99lbs) for the lighter tire set. Based on my ride log (I've been keeping a log since 2009) my battery range has increased by about 10% while maintaining my average speed of 13.5mph with an average gain of 71 feet per mile. Maximum downhill speeds on a measured downhill run are up by at least 5% amping up the downhill rush.
Also my current tire choice is more supple than the Plus tires and don't bounce around on a tight fast turn. The rear Plus tire had the bad habit of bouncing around in tight turns forcing me to occasionally counter steer. I tried different tire pressures to no avail.
Using the lighter/faster tires has added back that extra level of fun. But that doesn't mean I won't put the Plus set up back up if the situation calls for it.
