so i just switched the out the schwalbe marathon plus tires on my old hybridized raleigh mountain bike for some ritchey tom slicks and the increase in speed is definitely noticeable. the marathon pluses were 1.35" wide at 95psi max, while the new tom slicks are 1.0" at 100psi max, so those differences aren't tremendously dramatic, but the weight is truly where the new tires shine, 775 grams vs. 320 grams per tire. from the simple tire switch i just pulled 2 pounds of weight out of my wheel set and i'm kinda surprised how much i can actually notice the difference, especially when accelerating from a dead stop. the wheels now seem so much more inclined to start spinning.

the down side? don't know yet, i'll have to see if i pay for the increase in speed with more flats. my marathon pluses flatted twice in the year and a half i had them, which seemed kinda high for a tire advertised as "flat-proof". the bike is also now a bit closer to the ground which may make pedal strikes more common, but i'm somewhat accustomed to pulling up my turn side pedal in tight turns anyway.

lighter tires = flats. Actually, that's obviously not always true. For the most part though, when they reduce materials to save weight other things tend to suffer in certain bike parts.

I'll damn sure not ever use "fly-weight" tubes again. My vittoria randonneurs are pretty heavy but haven't flatted in over 2 years of daily commuting. I didn't even get that out of armadillos.....but who knows.

it's a confounding equation that i can't quite figure out. my regular everyday commuter is now my road bike that i roll with vittoria rubino pros at only 230 grams per tire, and i have yet to get a single flat with them in the thousands of miles i've ridden since may (knock on wood). and then on my hybrid when i had the fat and heavy marthon pluses that were allegedly "flat-proof" i had two flats in roughly a year and a half with them. i just can't make sense of my experiences because they seem so counter-intuitive.