Tyre pressure unimportant

Wurm said:

I use a 23c clincher rear w. 21c sew-up front, weigh +/- 88 kg/195 lb., and have tried various lower and higher PSI's. I've found 130 PSI front & 135 rear is almost always the best pressure to strike a good balance between RR and grip/handling with most tires I use.
Not saying the values Zipp gives are hard & fast rules, but I would say they're pretty close to optimal.

hmmmm, I'm the same weight as you ("at the moment"🙂), and I was as big a 'pressure-hog' as they came. I always (foolishly) used 150+ in my 20mm Conti GP clinchers, but I've weened myself down to about 110 front and 120/125 rear in 23mm clinchers, for smooth roads. But I guess tubulars deform differently

I hear ya Aussie, but 150+ is a fair amount more than 130-135, and then that's a fair amount more than your 110-120. Everybody's different tho', and the best way to find out is experiment for yourself.

But just as an observation/suggestion, my personal findings happen to coincide with what Zipp recommends for weight vs. PSI.

Wurm said:

But just as an observation/suggestion, my personal findings happen to coincide with what Zipp recommends for weight vs. PSI.

but are they all for tubulars? Someone can correct me if I'm wrong, but don't clinchers deform over bumps and cracks differently, in such a way that they can't handle as much pressure?

The way I weened myself off the high pressure was a bit pathetic. :p I'd start my ride with, say, 140 rear and 130 front, then squeeze a little air out after about 20kms, having convinced myself that they were too hard. Then I'd start the next day at 135/125 :p,,,etc. And prior to that there was the whole issue of getting myslef off 20mm tyres about 5 years ago! 🙂 The 23s I bought had to be Vredestein because they're rated to 145!