fa63

People get away with doing things wrong all the time, what would make anyone believe otherwise when it comes to tire pressures? In my experience, most lightweight people run too much pressure, and most heavyweight people run too little (or use a tire too narrow).

RT

I always go 5psi short of max, regardless of tire. Rides aren't too rough, and anything less feels like riding through sand. 195-200 lb.

StanSeven

I did it and got 324 lbs for the front and 12 in the rear. Maybe I'm doing something wrong.

Psimet2001 

Considering I am the one that built that formula years ago....you're riding tires too small for your large girth.

Maybe some of the rest of the posts have been a little too subtle for people to get, but there is no formula that will work for all riders and situations. Sidewall markings on tires are worthless because they are almost always higher than what a rim is listed at. Most rims don't list actual max pressures. When they do there is. A safety f actor involved, etc...

Ride what works. Use the formula as a general guide as a starting point. As you noticed - if it gives you something extremely high....well.....that's because you're too heavy for your current tires.

RT

Now I'm paying attention. Serious question though - for off the rack bikes, it is more difficult to find pressure ratings for rims. Is there a good resource somewhere?

Psimet2001 

Nope, but technology hasn't changed much. Keep it reasonable....or ride tubulars.

Reynolds 

FWIW, my weight is 150 and I run 23s at 95 F / 100-105 R.

Cowboy905

i just ride 10psi lower than the max on the tire.

Psimet2001 

It's as good as any method is for getting a starting point.....but...hopefully you realize that number on the sidewall is near meaningless....