Trying out the new tires on Indian Cyn

so_calif_rubi said:

It drove like a super, big pile of CRAP when we put in the manufacture recommended 50psi, however due to my endless, pantywaist-whining Richard took some air out and we're now running them at 30psi and they drive very, very nice now!!! I'm happy and not whining anymore....so now I won't end up in a ditch on my way down the mountain

Click to expand...

LOL

The MANUFACTURER DOESN'T RECOMMEND 50 PSI.



That's the MAXIMUM rated pressure, NOT the "recommended" pressure.

The tire maker just has no way of knowing what truck the tire may end up on...a suzuki samuri or a super duty, etc....all take DIFFERENT PSI.

Take the LOAD RATING that goes with that MAX psi on the sidewall...that's what 50 psi can support safely.

Now, take the total loaded weight of YOUR rig, divide by 4 if evenly distributed....that's roughly the psi you NEED to support as you tool along.

Typically add ~ 35% - 40% to that weight, to account for braking and handling load transfer, personal preferences in control vs softness, etc....and, compare THAT weight to your sidewall MAX rating.

That Weight/MAX Load = correct psi/MAX psi

So, if -

the tire is rated to support ~ 3,195 lb at 50 psi (A typical load range)

Your JK has a GVWR of ~ 5,500 lb

That means ~ 1,375 lb per corner, + 35% - 40% = ~ 1,788 lb to 1,925 lb load target

50 psi/3,195 lb = NEW PSI/1,925 lb

New PSI = ~ 28 psi to 30 psi range. (What you found by experimentation)



That's not infallible, as tire loading is not perfectly linear, but, it typically gets you into the ball park quickly.