Measured, but only by way of monitoring my average speeds over various rides using my Garmin 500. I have not kept records, but after two seasons of alternating between the two bikes, which are set up with identical positions and pretty similar gearing, I find I am somewhere between 0.5 and 1.0 mph slower overall on the Moulton for a given course. My rides are almost all solo, and my average speeds range from about 14 mph to about 17 mph. Climbing amounts are in the 50 to 80 feet per mile range most of the time.


FWIW, the Moulton is 5 lbs heavier. It uses Panaracer MiniLite tires that are 28mm wide. I am on 28mm wide Clement Strada LLG's on the Spectrum.


Gear range on the Moulton is 98 to 25 gear inches. On the Spectrum it's 110 to 29 g.i. (The pic of the spectrum is old; I have a triple crank on it now). The difference in the top end is not very meaningful because I can't remember the last time I pedaled above 28-30 mph or so.


On the road, the performance difference doesn't seem to be in any one particular area (flats, climbs, etc.). Although I can say, when climbing seated, they feel similar, but the Moulton is not good for out of the saddle climbing (front suspension bob), but that's not a big deal since I don't stand much anyways.


My gut says the Moulton has to have slightly higher Crr due to the smaller wheels, and probably slightly higher CdA too (due to the wide and wind catching space frame). But the right way to figure that stuff out is to do some Virtual Elevation type roll down tests using the auxiliary speed sensor I have for my Garmin. I just haven't bothered.


The only unfair disadvantage the Moulton has is that it has fenders and the Spectrum doesn't. The fenders are compact and well fitted, but I am sure they are adding some drag.


Something else to keep in mind is that you can draft (and be drafted) a bit closer on the Moulton with the smaller wheels.