The maximum recommended pressure is just that... the highest you should go. I can't imagine anyone rides with 173 psi unless that person is racing, weighs 130 lbs and has a team car ready to fix flats.
I have moved away from 23 or 25 and now ride 28's at 100 rear and 90 front. When I rode 23's it ws at 120 - 130 psi but no higher. It gave me a smooth comfortable ride. Experiment as to what works best for you. Just remember too little air means pinch flats.
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