You measure the bag to have it inflated at about 7 inches. For me on the front it is 51 psi on driver and 41 on passenger. I generally do 45 on each as the weight changes as I pack or have more or less liquids in tanks. 40 on a horrible road is good. 50-55 is fine on good asphalt roads. You have to remember it is not like tires. Under inflated doesn't me blow out. I still think maybe your tires are a bit over inflated. Nothing will fix that. I had a tech over inflate my tires after a lube job and didn't know it. My ride with Kelderman was horrible.