Originally Posted by
daihard
I'm a novice, but I wonder about the accuracy of the chart. I weigh 140 lbs (fully clothed). Even with a 20-pound luggage, I only give approximately 80 lbs to each wheel. I have 700x28 tyres, which means according to the chart, my tyre should have no higher than 60 psi. Does that really make sense? The pressure numbers written on the tyre are 100-120 (min-max) psi.
Don't forget to include the weight of the bike. If you're 140, the baggage is 20 and the bike is 25, that's 185. Around 60% of that (111) is on the rear wheel. So according to the chart, that 28mm tire should be at around 82 psi, which sounds totally reasonable to me. Pump it up to 85 or 90 if that makes you feel safer, but you'd be fine at 80.