Originally Posted by
rekmeyata
I had a similar situation with Kenda Drumlin tires, all the tire calculators I used for PSI none said more than 45 psi for 700x45c tires with a total of 275 pounds with me, gear and bike, but the tires looked flattish, so I kept putting more air, and they didn't start looking normal till they got to 80 psi which was the max on the sidewall.
I've toured for months on 50mm tires, with total bike weight ranging from 200-215lbs, so quite a bit less weight, and I ran usually 40f 45r ish, sometimes a bit less psi, sometimes a bit more, but not more than 50.
80 seems high to me, but very hard to compare with the extra 60-75 lbs.
What I would suggest is to not go by look, but really by feel.