Here’s a 47mm Schwalbe Marathon Supreme measuring 43mm actual width on a wide-ish rim.
Yes, those are my calipers.
I like the Marathon Supreme on the front. Cushy, and fast. I put in my best commute time after installing it. Not scientific, but it’s a nice-feeling tire.
I took the Marathon Supreme off the back, due to clearance issues, but I may try again with a 19mm rim. The Kwest I have on there now looks anemic next to the giant Supreme on the front. I also plan to go back to the S3X, in order to ride some climbing loops at lunchtime.