Originally Posted by
Dave Mayer
I don't get how discs are necessary to enable fatter tires.
I think a lot of people consider small calipers and discs to be the only options for road. Which, if you're only looking at bikes marketed explicitly under "road" categories, is somewhat true at the moment.
I also don't get the fat tire thing. Sure, weekend warriors in the First World are getting fatter, and more club-level riders are on clinchers (vs. tubulars), which was not the case 30 years ago. Both of this means riders need bigger tires for impact and pinch-flat resistance.
But if you are riding tubulars, which are pretty much immune to these problems, you can realise the benefits of smaller, lighter tires and rims, and still ride at relatively low inflation pressures.
In my experience, pinch flats are much less common than punctures on pavement, except with people who neglect their bikes and spend a lot of time running their tires near-flat. I don't think it's seen as a big enough issue to overpower the desire to not have to either throw out a tire or perform a cumbersome sewing repair in the event of a much more common puncture flat.
Width is also not
just a compromise for pinch resistance. Narrow tires have higher hysteresis losses when they're run squishy, and high tire drop can have other issues like casing wear and increased sidewall exposure. On the other hand, narrower tires do weigh less and have potential for improved aerodynamics... but the real world is complicated, and what's "optimal" in any given scenario has never really been well-characterized.
Perhaps most importantly, that characterization partly doesn't happen because net effects of tire width on paved performance are pretty tiny, hence a "why not" attitude toward wider tires.