Top Off Tires?

[Doc007]

Getting ready for a 200 mile trip this weekend and wondering if I need to top off my tires. My coach is under cover and the sun never shines on the tires.

Yesterday the temperature was 89 degrees. Coach has not moved in 2 months. Here is what my tire mfg recommends for my CAT Scale axle weights and what I found using my calibrated digital gauge.

Steer 123 DS 121 PS 122


Drive 110 DSOS 109 DSIS 109 PSOS 107.5 PSIS 108


Tag 100 DS 99 PS 97.5


Should I run all up to to recommended psi?


Note: I have never found a convenient place to get a 4 corner weigh, if that's what you are going to mention

[LETMGROW]

my answer to your question is YES.

[d23haynes57]

Originally Posted by Doc007

Getting ready for a 200 mile trip this weekend and wondering if I need to top off my tires. My coach is under cover and the sun never shines on the tires.

Yesterday the temperature was 89 degrees. Coach has not moved in 2 months. Here is what my tire mfg recommends for my CAT Scale axle weights and what I found using my calibrated digital gauge.

Steer 123 DS 121 PS 122


Drive 110 DSOS 109 DSIS 109 PSOS 107.5 PSIS 108


Tag 100 DS 99 PS 97.5


Should I run all up to to recommended psi?


Note: I have never found a convenient place to get a 4 corner weigh, if that's what you are going to mention

And what are the recommended pressures? Looks like you are pretty close or maybe even overinflated now.

[m0v1]

Yes, looks like every tire needs 5 more psi. If you like to run faster than 70, then add 10psi. A thermal camera looking at the carcasses after 4 or 5 hours of interstate driving on a hot day will convince somebody really fast the importance of tire pressure.

A blowout is the most likely way to have a really bad day in an RV. Do everything you can to avoid that.

The new Milwaukee cordless air compressor makes it really convenient to set pressures and walk away. It takes about 2 batteries to do all 8 tires on ours.

[Doc007]

Originally Posted by d23haynes57

And what are the recommended pressures? Looks like you are pretty close or maybe even overinflated now.

The recommended pressures are there...ie 123 for steers.

[Doc007]

Originally Posted by m0v1

Yes, looks like every tire needs 5 more psi. If you like to run faster than 70, then add 10psi. A thermal camera looking at the carcasses after 4 or 5 hours of interstate driving on a hot day will convince somebody really fast the importance of tire pressure.

A blowout is the most likely way to have a really bad day in an RV. Do everything you can to avoid that.

The new Milwaukee cordless air compressor makes it really convenient to set pressures and walk away. It takes about 2 batteries to do all 8 tires on ours.

Had a steer blowout. Not fun


I have a Viair RV450

[US1]

Am I seeing this correctly that the most any of the tires is low is 2.5 psi?

[m0v1]

That's what I am seeing too. Best practice is at or 5psi above the number in the charts and 5 more psi if you plan to run near the speed rating which is 75mph on his tires.

[Old-Biscuit]

On the travel day morning check/adjust tire pressures to recommended psi +5 psi

[Dutch Star Don]

Leave the tires alone, too many people mess with their tires when it's not needed. A tire gauge or a TPMS system will be off by a few psi from tire to tire as they're just not that accurate. Parking with the sun on one side or even driving with the sun on one side will raise the tires 3-5 psi from side to side.

Your tires, unless there is an issue, will not lose air. I run a TPMS system and can see their pressure every time I start the coach. Once, MAYBE twice a year I actually even them out by checking with a tire gauge and adding some air.

If you don't have TPMS, just do a walk around and check the tires visually. You're more likely to cause an issue with the valve stems by trying to force a tire gauge on frequently than the chances of running over a nail.

How often do you check your car tires???? I'm betting most don't touch them until the car gets serviced at 5K or 8K miles and that's when the dealer does it.

[4x4van]

I may be the odd one out here, but I wouldn't lose any sleep over those numbers. You are within 1-2%, and the one thing I never hear mentioned here is that the recommended pressures in a chart cover an "up to" load and are in 5psi increments. If your actual weight is just slightly over the previous weight/psi listing, then you already have a 5psi buffer. If you're getting close to the next step in the chart, then yes, adding an additional 5 psi buffer is smart.

[Gary RVRoamer]

Ditto what 4x4van said. If you are checking the cold psi every travel day, don't sweat 1-2 psi difference. The tables have a lot of windage built in with those 5 psi increments. But if you only check pressure every month or two or three, put in that extra 5 psi just to be sure you don't run a bit low somewhere in that long interval.

[High Road Travelers]

To me it looks like you are about as close as you can get to perfection.
Thanks,

[dvspl]

Originally Posted by Gary RVRoamer

Ditto what 4x4van said. If you are checking the cold psi every travel day, don't sweat 1-2 psi difference. The tables have a lot of windage built in with those 5 psi increments. But if you only check pressure every month or two or three, put in that extra 5 psi just to be sure you don't run a bit low somewhere in that long interval.

I agree with Gary. I don't lose any sleep over a few psi. But if you're going to worry about it, put in whatever makes you feel comfortable.