Last May I decided to try a narrower [700Cx20 versus 700Cx23] Continental Grand Prix 4000 tire as a replacement for my previous set of Conti GP4000s. This tire allows for a max 160 PSI tire pressure. In terms of ride and speed, I do not think I can tell a real difference in this tire’s performance and my 120 PSI Conti’s.
I can tell that getting the tire onto the rim, given a tighter bead is much more difficult. I have to use a leveler to do so and have pinched several new tubes. Further, it is possible to have a piece of tube under the bead, even after checking, and having a blow-out as you near 120-140 PSI. I have experienced both.
If there is any benefit to these tires, it is not worth the cost of damaged tubes. Luckily, when I’ve had to do repairs on the road, I’ve not lost a tube due to my error.
At this point, I’ll probably wait until the spring to replace this set. The center of the tire has not worn too flat. I’m running about 150 PSI.