While testing a 2016 Focus RS for the comparison test (link: Ford Focus RS vs Subaru WRX STI vs Mitsubishi Evo X MR), I caught up to a 2016 Mustang Shelby GT350R and had a friendly head-to-head battle. Both cars were completely stock. The video doesn't capture just how good that car sounds. We had a chat afterwords and the owner was very cool about it. His rear tires were starting to look old and he told me it felt a little less grippy than he was used to, so they could have been heat cycled out. Our track is also short and technical, so high hp cars don't get much room to stretch their legs, robbing them of some of the advantage they'd have at a power and/or longer track. The Focus had the optional Michelin Pilot Sport Cup 2 tires. Check out the video below for a couple of laps.
I've been a huge fan of Michelin PSS tires and exclusively bought them for the Mustang over the last four years. So how did I end up here? This year, I was hugely interested in trying an "R-comp" tire. I had my eyes set on Bridgestone Potenza RE-71R's for two simple reasons: price and reputation. Although not a true "R-comp" tire on paper, it performs like one by the account of every single test and review I've read (down to wear rates...). They seem like they're easily the most affordable (from a big brand) R-comp tire and combine that with a reputation for having tons of grip, it was an easy top contender. I had my concerns, though. For one, I'm told and have read that they are an autox tire, not really designed for high speed, pressure, and temps associated with open track. For another, the Mustang is a heavy car (as far as track cars are concerned) being roughly 3,800 lb. (including driver), which will amplify the unwanted open track loads.…