I have a set of tubulars I've been racing road on for a couple years. I'm thinking about using them for Cross this season. However, I want to know how much of an advantage I'll be getting over clinchers given that I'm pretty light weight. I weigh around 135-140lbs and run my CX clinchers around 30-40psi which feels really soft but I think I can go lower. Will I be able to run tubs a LOT lower in pressure? What are the advantages otherwise?
I am ~125 lbs when I'm race fit. Yes, tubulars are FAR superior to clinchers even if you're light. How low you can go depends upon your riding style and the conditions, but I've raced as low as about 20f/22r on smooth courses.
I weigh 145 and usually run my tubulars between 25 and 28 psi. I start to worry about rolling them below 25 (the grassy spots on FL courses often have quite a bit of traction). I've run clinchers in the high 20's and gotten away with it, but there are always a few spots I have to finesse.
But it's not just about pressure. The casings on tubulars are usually more supple than their clincher counterparts, so even if you can run the clinchers at comparable pressure, the tubulars will likely still perform better.