I certainly understand your concern, I recently paid nearly $4K for a set of six 22.5" tires for our motorhome, a lot of dough for rubber for sure. All the answers above are great advice, simply set your tire pressures when tires are cold, cold does not indicate a certain temp, just means when tires have not been used, best to do in the morning as tires have been resting/cooling down overnight. Set them at your desired pressure in the morning, we use 90psi for our motorhome tires, and don't worry about increase in psi while going down the road, perfectly normal as tire manufacturer engineers have already accounted for this. Even when not moving down the road our TPMS indicates psi increases, although minor, when the sun is beaming down on the side of the coach where tires are exposed. That all being said, you spent the money for them and if you prefer to do it the way you have in the past, you were happy with the results and that's all that counts.
