Since Abu Mahendra mentioned the 20x1.5 Marathon Racer, it just so happened that a pair of it came with my Mu D8.

I can tell you with certainty that when it comes to rolling resistance, they can't hold a candle to the Supremes - to the order of having to torque over one gear lower on the same surfaces just to get over the extra drag. I have to pump them up to at least 80R/75F psi (maximum recommended is 85 psi) to get something close to the rolling resistance of the Supremes at 70R/65F psi - at which point what precious little suppleness they had is all but gone.

Since both the Mu and the Speed have identical wheelsets and rear cassettes, I swapped the Racers over onto the Speed, since its chromoly frame helps take the edge of off their high-pressure harshness somewhat. The more supple Supremes run that much nicer under the Mu's more brittle aluminum frame.

The bottom line is that it's just unfortunate that the Supreme had been discontinued in the 406 size, wuth no apparent, viable alternative in sight for folding bike riders who don't want a strictly BMX tire.