CharlesOK, I thought your rims looked silver, are they actually white as you just mentioned? These pics are required to be low resolution.
I really must apologize for my maintenence-laziness, and as an engineer I know better, too. I even went to a lot of trouble looking for an air compressor when we first got the RV, and that search created many forum posts (see the thread 'Portable Air Compressors' in Class C Motorhomes in June last year).
I will try to be more dilligent. I do often go around and hit the tires with a fist, but I must admit the sound never tells me much.
Many new cars come with air pressure valve monitoring systems; seems like all RV's should have this as mandatory hardware - what do you folks think?