Originally Posted by
12strings
This seems high if comfort and/or off-road grip is the goal.
I run 30mm cross tires on my bike at 40 psi for gravel and grass. (I weight 160lbs).
Actually I've run 60psi on my 25mm road tires without any problems other than slowing me down and feeling a bit too squishy.
Yeah sure, you can go lower for gravel and grass of course.
The pressures I gave were more for road.
For road, generally anything below 80 psi under 30mm the resistance starts to go up under 80, but 60 still isn't bad. For me, that would be a pinch flat problem on a tubed tire (which most narrow tires are).
Anything from 30-45mm is going to start to show markedly increase in resistance below 45 psi. 30-45 change typically increases resistance by 20 watts a pair, which can be a 50% increase in resistance for a good set of tires.
But yeah, gravel, grass, sand changes things. Off road 50psi for a 25mm, and 35psi for a 40mm tires is fine. Going lower can work, but you increase the possibility of pinch flats, hitting the rim, and/or burping. Its all doable though with the right technique and circumstannces...