I get asked this question quite a bit. I think that after reading various posts on tire inflation and load, some people want to complain a bit and are hoping to use the excuse that it is too much work to monitor tire pressure every travel day.
Here is an example from a trailer owner:
"I've noticed that 50 psi cold at sea level at ambient 65F is 54-55F at 6,000 to 7,000 feet.
While touring should I deflate to 50 psi cold at 7,000 feet if I'm hanging around there for a day or two?"
I am hoping that if I share my personal experience, it will provide a down to earth view on the topic that some want to turn into "Rocket Science"
I just finished a two-month cross-country trip. Ohio > Oregon > Seattle > Calgary, Canada > Yellowstone > Ohio in my Class-C MH with LT type tires that are 7 years old but have always been covered whenever parked for more than a couple of days, Always running inflation about 15 psi above what is needed for actual max load based on 4 position scale weights that are confirmed to have not changed significantly each year with a trip across CAT scales.
Fastest I ever run is 70 mph but most of the 7,400 mile trip was with cruise set at 62mph. In other words, the tires have had a good life with good care.
Elevation ranged from about 25' at Olympic Nat Park to 8,000'+ in Rockies. Morning temperature ranged from 33 F to 94 F. I have TPMS (both internal and external) so I am able to constantly monitor both pressure and temperature.
I adjusted the tires once during the trip. I think I needed to add from 1 to 4 psi in the 6 tires. Since I run a nice inflation cushion of +25% I don't get all bent out of shape when the cold inflation is off by 3 to 5 psi from my goal.
You don't have to make the task of monitoring inflation a big deal. While I may set my pressure to +/- 0.5 psi, you certainly don't need to be that fanatical, and I would consider it completely acceptable to be +/- 2% for the average user as long as the "goal" cold inflation has an appropriate safety margin.
With TPMS I simply hit the button a couple times a day and get a real time reading of tire temperature and pressure. Yes, the temperatures vary and so do the pressures, but unless I see a sudden drop in pressure and there have been no external changes such as a sudden rainfall or one side constantly hotter than the other after spending hours with one side in full sun, I just do not worry about it.
Relax. Let your TPMS monitor your tires and enjoy the scenery.
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PLEASE do not install the valve stem tire monitoring sensors UNLESS you have metal, not rubber, valve stems. Though this is a suggestion by some vendors, it should be a requirement. I experienced two valve stem failures. one of which was at highway speed and could have been catastrophic. The sensors weigh about 1/2 ounce and as a tire rotates, exerts centrifugal force which deforms the base of a rubber valve stem. This can lead to a gradual loss of pressure and in my case, a complete failure which could have lead to complete loss of control. The tires were Michelin with 15,000 miles on a 3/4 Ton Dodge Ram diesel towing a 6,000 lb trailer. The system works great, but PLEASE convert your tires to metal valve stems before installing.
ReplyDeleteGood observation and comment. It is too bad that so many vehicle MFG cut corners to save a few pennies. Standard rubber valves are rated 65 psi Max. So when the tire requires 65 they feel it is OK to use a "snap-in" valve. Read my post on What valve to use from January 23, 2013 for more details.
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