FYI, two guys with big Sport Touring BMWs, different models, in riding group both had PR5 on front and both lasted about 3,000 miles. Both went back to PR4gt.
FYI, they both also had a broken thermostat which their bikes was overheating. Thermostat broke in two when removed from both bikes. Both bikes were also out of commission for about two weeks wait on the part.
Both the tires and thermostat happen on both bikes this year, about a month apart from each other.
Current Bike> '14 FJR ES, '17 Versys-X 300 ABS
Past Bikes > '09 Ninja 250r, '00 XT225 (blew piston), '03 Goldwing, '07 DR650, '07 XT225, '12 NC700x