Originally Posted by
Aubergine
I can't say how this fits into modern wheels and tires, but back in the late 70s and 80s my sewup wheels were noticeably better at cornering than my clinchers. It was my impression that the clincher tires were somewhat oval, so grip was lost suddenly if I leaned over the "edge" of the oval. Whereas the tubulars had no edge, so were more predictable. I am far from having very good balance but I was able to catch a skid on the tubulars. On clinchers, I just went bang.
I rode/raced on tubulars exclusively from 1964 to about 1990, and I don't remember my clinchers, once I made the transition, being noticeably inferior to tubulars for cornering. I'd crashed enough times on tubulars by then to have likely become more cautious at cornering, both on tubulars and on clinchers, though.