Yes, another tire question...

goufgators wrote:
I've weighed and according to the Goodyear chart I should run 80 psi in all tires. The MH handles very good at 80 but the tires increase in pressure as they heat up and it's not uncommon for them to pick up 15 psi. At that increased pressure (95)handling become less than comfortable. Question: Knowing that the tires will increase in pressure rather fast, would I be taking a chance by inflating cold to say something less than that required by weight...say 75 rather than the 80 knowing that pressure would be up to the required 80 psi and beyond within only a very few miles.

No, you should not, under any conditions, lower the pressure below the indicated minimum. Remember, that chart shows the minimum required psi to carry that weight. You might be better served to increase the cold psi 5 pounds or so. You might get less heat and pressure rise.

Do not be concerned with tire pressure rise while driving, it's normal to see that amount of rise. Simply keep them inflated to the COLD tire pressure listed on the manufacturers tire placard in the RV.
Ignore those tire pressure/load charts and run what the mfgr. states. That is what the RMA-Rubber Manufacturers Association states in CH 4,pg 51 of their RV tire care pdf.

"However, never use inflation pressure lower than
specified by the vehicle tire placard, certification
label or owner’s manual."

You need to stay within specified cold pressures for your coach weight. With the average rig spending more time waiting for us to decide it's time to go, sitting on under inflated tires may cause unseen damage that could shorten the tires life with rather dramatic results.

Tires will effect ride and control but there are other components also in play. Check your sway bar bushings particularly the rear. The original Ford installed material doesn't last very long. Have the alignment check by a heavy truck service center (not your local RV Service Center) with the coach loaded as close to your normal weight as possible. There are front and rear add on devices that will help calm the couch but at this point your starting to spend a bit of camping/fuel money. There are ways to calm a coach but reducing tire pressures below recommended is best avoided.

At the least, keep the proper inflation psi for cold. Heat is one of the worst things for tires and leads to failures. Under inflated/overloaded tires creates lots of heat...very bad! Perhaps moving the load around if it could be better balanced, or steering stabilizer, or shocks or something suspension related. I recently spent money on tires and I want them to last. Proper pressure maintained is one of the best things you can do. Good luck!

There is a reason why the manufacturer has a tire chart and why they say to inflate the tires to the specified temperature when the tires are COLD.
Driving around with a fully loaded coach, or even an empty coach, still puts a large load on your tires. Enough of a load that if you drive with 75 PSI in them, there is a good chance you will damage them and at some point in the future they may fail.
Actually, to be safe, if the chart specs 80psi, I would increase that by at least 5 PSI to 85 PSI.
The flexing of the tires is one thing that cause them to heat up when driven. Inflating to 85 PSI may decrease the flexing enough so that the tire pressure increases less than 15 PSI. In any case, at 85 PSI it gives you a little margin of safety for the inevitable small loss of air.
If you inflate the tires to 80 PSI and your coach handling suffers when they increase to 95 PSI because of heat, the problem is with the coach and not the tires. Correct the suspension, loading, or alignment issues and your coach should handle like everyone else's when their tires get warm under NORMAL circumstances.