42 psi is the rear tire pressure for rider / passenger and bags. 36 psi is the rear tire's recommended pressure for rider only. The front is always 36 psi regardless. Owner's Manual snippet attached. "A" Spec (Pirelli) tires (GT for Michelin) are available for certain models as a beefier version with more rubber and stiffer side-walls to accommodate heavier loads. The previous Multistrada Gran Tourismo came equipped with Pirelli Ducati OEM "D Spec" Angel GT tires. The "D Spec" have since been dropped by Pirelli for the Angel GT2 model which are now offered as Regular or "A Spec". Here's what Michelin states about it's “Gran Turismo” GT version of the Road 5: "The Michelin Road 5 GT tire delivers all of the wet grip performance of the Michelin Road 5 tire with an all new architecture designed to provide maximum stability for GT-class motorcycles."
Interestingly, I had the rear wheel out yesterday, as I've been fitting a new chain and sprockets. My new rear tyre, which I've done about 300 miles on, was all roughed up in the centre. I'd done a gentle ride home from my girlfriend's place, about 60 miles or so of dual carriageways, mostly around 65-70mph (taking it steady due to knackered chain). I'd asked the tyre place to put 42psi in the tyre when it was fitted, but I didn't check it. Either way, I'll definitely be dropping the tyre pressure now!
