Last Sunday fitness ride of the season today. Lately we've had several slower riders joining us, so I decide to take my mountain bike to try out my new 26 x 2.35 Big Apples. When I get to the meeting spot there are just two of the better riders there with road bikes. They sort of give me a funny look and ask if I'm coming along with them today.
I had to work a lot harder, but I did a pretty decent job keeping pace. The lack of an aero position going into the wind on the way back definitely held me back a bit. I would have been absolutely wiped if I didn't have the bar ends. I wouldn't have wanted to do much more than the 69km at that pace though.
I really love the ride of the Big Apples which I had inflated to 40psi. They really smooth out the road and roll surprisingly fast. Even the rumble strips on the highway are tolerable to ride on. My fender tire clearance is tight, so I'd occasionally get rocks rolling between the two.
If you are going to use medium-to-fat tires on a bike all the time, then you should really consider switching out normal-width rims for wider "downhill"-style rims.
Fat tires work best on w-i-d-e rims. You can drop the inflation pressures lower, while still retaining good handling qualities.
Also rocks rolling under the fenders: yea, I've heard of that.
I looked a long time for plastic fenders that would fit around BA's while still leaving decent room, but still fit into a normal bicycle frame,,,,,, and didn't find any. The problem is not the tire's width, but the tire's centerline outer diameter. It comes very close to rubbing at the front and back edge of most every fender out there.