Totally fine and normal.
Tire pressure goes up about 2% for every 10F rise in temp. If the tires are running or sitting in the sun on one side, the temp. can go up a lot more than the cold inflation pressure. A 25% rise in pressure would suggest a temp. rise of about 100F (above the prevailing ambient temp. when the cold inflation pressure was set), which isn't unreasonable from the sun beating down on the tires after a long trip.
I suggest that you simply measure the pressure after sitting in full shade for at least 3 hours. If not back down to near what you cold inflated them to originally (assuming you did inflate them correctly), then you have an issue. It's good practice to check your tire pressure before heading off each day, especially if the ambient outdoor temp. has changed much.
The max. sidewall pressure indicated on the tires is the max. cold inflation temp. (at prevailing ambient temp) and is NOT the max. the tire pressure should ever reach. The "max" is what you should always set them to - 50 psi for LRC and 65 for LRD.
Tires are designed and tested to withstand about 3 times their max. pressure rating. and are designed to tolerate the pressure increase that happens when travelling at highway speeds. You are nowhere near the danger zone.
Never deflate your tires to adjust the pressure while travelling. Running under-inflated can cause serious internal damage leading to premature failure (blowout) at highway speed. Not good...
For lots and lots of info. on
RV tire safety from a tire expert, go to
this website
