40-42psi.
Remember that car/cage manuals are not only written by engineers. Salesmen (and lawyers) get input too. It's my lifetime experience that recommended psi's for tires are lower than optimal for tire wear, and even optimal handling/braking. People like a smooth ride, and soft tires give them one. Manual writers could give a rat's ass if your tires wear out in no time.
Also, manuals are only written for OEM tires, not every tire you may ever replace them with.
I don't know about today, but for decades OEM tires on new vehicles were always mediocre at best (to hold down overall cost).
It sometimes goes the other way also. I owned a Indian Scout, a small, sporty cruiser. The manual asked for 40/42 psi, in it's OEM craptastic Kenda tires. Those tires, at that pressure were greased wooden hoops. The rear was comically easy to spin up and the ride was rock hard. No bueno. I found running the tires at 30/32 was a huge improvement to grip and ride quality. Most owners agreed, Indian in general seems to recommend near or at the max PSI for the tires, I guess to try and extend tread life or fuel economy, who knows. Suzuki did the same thing, even on it's sportbikes the manual called for high pressures for really no reason. A GSXR apparently needs 42psi, where a CBR, ZX, or R6 only needs 32. For the exact same tires, same wheels, similar weight and power.
