We've always been fans of Vittoria tires. The longevity of the brand is due to it's relentless search for optimal performance at the Pro level, and passing those features down their product range.
The Open Corsa SC (Service Course) II, is from the top end of the line. Using the same high thread count (320 TPI) as the tubular version, riders have the opportunity to experience similar benefits on clincher wheelsets.
We chose the 25mm for our review. There is a trend among racers (pro and amateur) towards wider rims and slightly wider rubber. There's plenty of science to back that up, but we wanted some first hand.
We mounted the SC's on SRAM 30mm deep aero wheels and used the recommened Vittoria latex tubes. Most high end tubulars also use latex inner tubes. Again, the suppleness of the whole package is what gives a tubular it's unique quality.
The first two hour ride by our tester, who was counting on a softer feel to compensate for some injury recovery issues, was over mixed pavement conditions. The test pilot reported a distinct level of cushioning over a similar high TPI 23mm tire used prior. At times our tester ran much lower pressures than usually suggested. Even at 75psi the tire did not squirm or feel particularly 'slow' or at risk of bottoming out on the rim.
Cornering was confident with a grippy compound (ISOgrip is Vittoria's designation). The tread pattern is a fairly traditional "all condition", that should work well in the wet. Again, the tubular version of this tire is placed throughout the Pro peloton year round.
Not everyone will choose this tire for everyday riding. It's at the upper end of the price scale. But paired up with latex tubes, our testers consider the ride and perfomance second only to a high end tubular. We also are impressed with the durablity of the rubber compound, after several weeks or everyday use, the rubber looks as fresh as much less expensive 'training' tires.
Most of our staff at localcycling.com ride tubulars in racing conditions, but would find the Open Corsa SC a great choice as well.