Well it's known that a tire will last longer with a higher psi, but you also compromise traction. You have to find that happy medium.
We all know that statement is not true for auto tires. Over inflation not only compromises handling and risks exceeding the tire manufacturer's load limit, it tends to wear out the center tread resulting in tires wearing out prematurely. Personally, I have not seen any difference in motorcycle tire life with motorcycle tires inflated to 33 psi vs. 36 psi vs. 38 psi vs. 40 psi. Anybody got any data to the contrary?
Motorcycle Superstore seems to think motorcycle tires wear like car tires. "When your tires are over inflates the middles section tends to wear faster than the sides of the section."
Motorcycle Tire Buyer's Guide: Everything You Need to Know! - Motorcycle Superstore
Canyon Chasers has this to say about that - "Many riders still believe that running the max psi number listed on the sidewall will ensure you'll get the maximum life out of your tire. But as tire's have evolved this is no longer the case. Running max-pressure, or too high pressures can actually cause the tire to wear out faster. Yes, you read right; keeping pressure higher will actually make the tire wear out quicker. When a tire is over-inflated (and by over-inflated we mean, higher than the manufacturers recommendation) you make the contact patch smaller because the tire is unable to flex as much, this focuses the wear onto a smaller surface, increasing heat and wear."
Motorcycle Tires Explained | Canyon Chasers Motorcycle Sport Touring
Motorcycle.com thinks - "Overinflating tires does not increase load-carrying capacity, but will result in a hard ride and accelerated tire wear in the center of the contact patch."
Motorcycle Tires 101
Moto-USA gives this advice - "If for some reason your tires are losing more than two psi per month, the tire, valve, or wheel may be damaged." and unequivocally states - "Riding on tires with too much air is equally as dangerous. The tires are more likely to be cut, punctured, or broken by sudden impact. Overinflating will cause the bike to ride hard and will cause the tire to wear out quickly in the center of the contact patch."
Motorcycle Tires Product Guide - Motorcycle USA
Someone with lots of experience - T.J.Tennent/Engineering Manager, Firestone Consumer Products, Government Products, Bridgestone Motorcycle Karting Products. An avid long-time motorcycle rider, Tennent in his spare time is also an instructor for the Motorcycle Safety Foundation and is Chairman of the Tire Rim Association, Motorcycle Sub-Committee, which decides specifications for bike wheels, tires and tubes that are sold here in the U.S. "Tennent also advises that a rider should run their tire pressures between one and two psi above the manufacturer’s recommendation. That way you take into account any changes in weather (heat and cold can affect pressures). But also if you are only going to do the bare minimum and check them just once a month, it will compensate for that too, as on average tires will lose one psi every four weeks under normal riding conditions.
https://rideapart.com/articles/the-dos-and-donts-of-motorcycle-tires
Dunlop's statement on cupping - "there are steps that can be taken to minimize cupping and uneven wear on a motorcycle: Maintain your motorcycle and particularly your front and suspension. Avoid hard braking whenever possible. Braking causes the tire to grab and wear in one direction. When braking is applied to the front tire, the load transfer over-flexes the tire and increases the tendency for cupping and uneven wear. Maintain your tire pressures. Under inflation and overloading of motorcycle tires are significant causes of cupping and uneven wear, particularly in association with hard braking and/or trailer use."
FAQ | Dunlop Motorcycle