I see this is an old thread, but I found 700x40 marathon supremes to not be remotely comparable to 26x2.0 BAs (80% of the width but maybe not 80% the volume, not even 80% of the awesomeness). The BAs I thought had a sweet spot at 40psi but were just fine down to 25ish, the 40mm supremes seemed to want to be pumped up to at least the upper quintile of their recommended pressure range. I love the 2.0 BA and keep those on my all weather commuter, and I have 2.35 BAs on a tandem which are much more than 118% as awesome as the 2.0s. But my road bike I have downsized to 28mm supremes and I like those a lot but I keep them pumped up pretty high and they are just not in the same category of tire.
Last edited by HardyWeinberg; 07-24-14 at 05:53 PM.