Originally Posted by bark_eater

I was wondering how rim width should be factored into the various tire pressure verses tire volume and rider weight?
I'm at about 230 right now with 25-30 pounds of every thing else. I have Panaracer Grave kings in 28mm mounted on CR18 rims that are approximately 18mm interior width. The tire are rated at 105psi. I had the rear tire up past 110psi and the ride was harsh. I got a pump with a reliable gauge and got the pressure down to 105 psi. and the ride is much smoother. I am cringing every time I hit a obstruction or pothole, but so far so good.
The Dorky pants 15% drop charts seem to indicate 118 psi for a rear tire at my weight.
My question is how do I do I determine what rims the charts are based on and how do I gauge the extra volume added to the tire and how much pressure can be dropped? thanks, Woody