Bought a RP3(7.875x2) and put it on my Truth. I've been reading that RP3 PSI should be set to close to your body weight or 1/4inch sag. Well 1/4inch sag is ~57psi. I weigh 170 with gear. That seems pretty odd that the psi is so low. Is it due to Ells Truth geometry? At 57psi I get quite a bit of sag when peddling uphill which I assume is expected. Should I pump it up more?