Originally Posted by
Andy_K
I'm really glad you're here preaching this good news. Seriously. I'm a convert.
After reading something you wrote to this effect a few months ago I bought some 700x50 (29x2.0) Marathon Supremes for my rain bike. Despite being fantastically wide, they are faster than the 700x42 Conti TownRides they replaced. I'm assuming that in this case the faster has more to do with the tire itself than the increase in width, but the increase in width doesn't seem to have hurt at all. The Marathon Supremes even feel like they roll better than the 700x28 RiBMos I run on my cross bike.
I'm guessing a two-inch-wide tire actually would register some negative wind-resistance effects if I were faster, but at around 18 mph where I usually cruise it doesn't seem to be a problem. Maybe I've just had too much of the Jobst Brandt kool aid to notice.
Width in itself reduces RR, but so does high pressure - which normally comes with narrower. The tie breakers can be compound quality and wall thinness. Supremes are thick, but the quality of the compound is outstanding - which is why they're so pricey. (Compounds also have different biases towards speed, dry and wet grip, wear resistance, puncture resistance, etc - it isn't just better/worse.)
I'm really surprised at your running 700x50 though! That is wide. But you've chosen probably the outstanding tyre for the job. You can also pull your RR down some more by using a high quality latex inner tube and heavily talcing the tube and inside of the tyre.
(If bike magazines did their jobs properly - for us instead of advertisers - then they'd test tyres for all the above properties and we'd have numerical data.)