Michelin LTX M/S2 - Inflation Preferences

[Al and Missy]

Lost me at the Nitrogen.

[Photobum]

theoretically they stay cooler with nitrogen...

[lewster]

Originally Posted by TheDuke

For the best tire life, mileage, wear and over all performance, you should always run the max pressure listed on the sidewall. Tires that are underinflated run at hotter temps than tires that are inflated to max pressures. Many tires that blow out have usually been underinflated at some time in their life. Yes, you may notice a slight degradation in the ride, however you will have less sway and a better overall experience with your tire. For the best overall tire performance have nitrogen installed at max pressure. LT tires can even be inflated 10% over the sidewall max pressure per manufacturer specs for heavy hauling. I have never done so, because I never overload a tire, and I have never had any trouble.

Not wanting to troll this issue, but your source for this information, or your qualifications and/or certifications in the tire industry are…………..?

[GammaDog]

I run mine at 80 as recommended by Colonial Airstream. 12,000 miles so far and no signs of wear at all... certainly not the heavy center tread wear I'd associate with over inflation. This is a thought provoking discussion.

As for ride, there was that time we set up to camp and found a dinner fork in the ceiling that had been left on the breakfast table.... hmmmmm.

[Wayne&Sam]

Please, not nitrogen again....

[ROBERT CROSS]

Originally Posted by Wayne&Sam

Please, not nitrogen again....

I fill mine with compressed 'atmosphere'....then slowly let just the 21% that isn't N out.

Bob

[BoldAdventure]

Alright, so I ran 80psi. Inflated this morning, we drove for 2 hours from Parker, AZ to Yuma, AZ next to the proving grounds. 110 miles. I checked the PSI 75 miles into the trip with about 50 mins left. PSI had reached 89 psi in all tires. Ambient air temp outside was 71, but I am driving through the desert.

I can't tell if it was smoother or not honestly.

But I know where it wasn't smoother and perhaps worse. Washboard road! We drove 5 miles of washboard here to our spot in Yuma. 80psi might be fine on smooth US interstate, but I don't know about regular roads in the desert and dirt/gravel roads. That's really harsh.



So another question for this thread. When off-roading, I use my Staun tire deflators and take the truck down to 20psi. Nice, smooth ride. I would think this technique would work on the Airstream as well, since we are not on pavement, and traveling at very low speeds. Thoughts?

Probably wouldn't take the Airstream that low, but I might take it down to 35 or 40psi. Generally you want the tire to kind of look flat when off roading so it rolls over rocks and stuff easier.

[Howard L.]

Originally Posted by BoldAdventure

If this is true, why then are manufacturers putting vehicles on lots with under inflated tires?

There seems to be no consensus or standard.

Manufacturers will list the recommended inflation pressure on door jam. You will find those PSIs, when checked against the tire inflation load chart, will match the tires to the axle max wt. My 2500 Chevy is fitted with "E" rated tires, yet door placard calls for front 60psi and rear 75psi. Those inflations bring the two tires equal to the axle certification on front and rear. Is called lawyer inflation pressure.

I run 75 to 80 psi on my ST Maxxis "15 inch E"s. I see no indication of rough ride to my 30 FC interior or exterior (and ST tires have a stiffer sidewall than the LTs that many now use). I would think for every pound you lower the pressure, the more safety margin lost. I also wonder how much air you have to let out to really get a ride smooth enough to matter. Sidewall pressure will give you the coolest running tire. Other than road hazards, or manufacturing defects, it's the heat build up that will park you on the side of the road.

[switz]

With the Classic crossing the scales with about 8,160 pounds on the trailer axles, we run 75 psi in our 16" Michelins and temperature and pressure rise are fine even in the summer heat in the Southwest.

[Siegmann]

Originally Posted by BoldAdventure

Alright, so I ran 80psi. Inflated this morning, we drove for 2 hours from Parker, AZ to Yuma, AZ next to the proving grounds. 110 miles. I checked the PSI 75 miles into the trip with about 50 mins left. PSI had reached 89 psi in all tires. Ambient air temp outside was 71, but I am driving through the desert.

I can't tell if it was smoother or not honestly.

But I know where it wasn't smoother and perhaps worse. Washboard road! We drove 5 miles of washboard here to our spot in Yuma. 80psi might be fine on smooth US interstate, but I don't know about regular roads in the desert and dirt/gravel roads. That's really harsh.



So another question for this thread. When off-roading, I use my Staun tire deflators and take the truck down to 20psi. Nice, smooth ride. I would think this technique would work on the Airstream as well, since we are not on pavement, and traveling at very low speeds. Thoughts?

Probably wouldn't take the Airstream that low, but I might take it down to 35 or 40psi. Generally you want the tire to kind of look flat when off roading so it rolls over rocks and stuff easier.

I would expect that when driven at low speeds on a smooth road your tires would do fine at a lower pressure. But if you are on a washboarded road, the dynamic forces will be much greater than a smooth road, and I would hesitate to drop the pressure below Michelin's inflation charts in order to baby the Airstream. If disturbed contents indicated a turbulent drive, I would just take those 5 miles a little slower.

[tjdonahoe]

Why worry about temperature build up? An asphalt highway will be very warm and hold the heat from the sun, my original gyms have 21000 miles with 50 per cent tread left, checked a couple times a year kept at 65 lbs pressure, don't worry about the rest, My big truck steer tires are kept ay 120 lbs, after a 500 mile run on a hot summer day they are at 132 lbs pressure it is fine , everything is normal.....

[PKI]

Originally Posted by ROBERT CROSS

I fill mine with compressed 'atmosphere'....then slowly let just the 21% that isn't N out.

Bob

At what rate do you let it out and do you use the left or right hand wrench with a pressure or volume gage? Pat

[TheDuke]

Originally Posted by BoldAdventure

If this is true, why then are manufacturers putting vehicles on lots with under inflated tires?

There seems to be no consensus or standard.

All automobile manufacturers list the inflation pressures that make their particular vehicle ride the best. They are not interested in making the tires give the longest service....haven't you noticed that they all sell tires? As for my experience, I grew up in a family owned trucking company, that had over 50 trucks! None of the Truck manufacturers list anything in the door jambs like auto company's do. I have also been towing RV's for more than 25 years, all shapes and sizes in all of the lower forty eight. No, I am not certified in the tire industry. I graduated from the school of "hard knocks!" That is where you have to use "common sense" and hard work to be successful. And yes, I have been self-employed all of my life and many would call me successful to have what I have and to be retired at 55 years of age. And no, I haven't inherited one cent! I made mine the old fashioned way...."I Earned IT!" Next?

[slowmover]

It's the forces on tandem axle trailers that themselves call for full sidewall pressure. Turns, curves, etc, are enough to subject the tire plies to tearing. Interply shear. Run full pressure and on to the next subject.

[CapriRacer]

Don't forget the rule of thumb:

You want to see NO MORE than a 10% pressure build up.

If you see 15%, you need to fix that IMMEDIATELY - as in more pressure, a larger tire size, slowing down, etc.

If you are experiencing 10% to 15%, you DO have to fix it, but you don't have to do it right away.

Also, achieving a 10% pressure build up is NOT a goal. It is an indicator if something is wrong. This is NOT to say that everything is fine if you get less than 10% - It's that MORE than 10% is definitely a problem.

[Alphonse]

Originally Posted by BoldAdventure

Alright, so I ran 80psi. Inflated this morning, we drove for 2 hours from Parker, AZ to Yuma, AZ next to the proving grounds. 110 miles. I checked the PSI 75 miles into the trip with about 50 mins left. PSI had reached 89 psi in all tires. Ambient air temp outside was 71, but I am driving through the desert.

. . . .

BA, how fast were you driving?

[dznf0g]

Originally Posted by CapriRacer

Don't forget the rule of thumb:

You want to see NO MORE than a 10% pressure build up.

If you see 15%, you need to fix that IMMEDIATELY - as in more pressure, a larger tire size, slowing down, etc.

If you are experiencing 10% to 15%, you DO have to fix it, but you don't have to do it right away.

Also, achieving a 10% pressure build up is NOT a goal. It is an indicator if something is wrong. This is NOT to say that everything is fine if you get less than 10% - It's that MORE than 10% is definitely a problem.

Do you need to account for ambient temperature rise when noting percent rise throughout the day? As well as sun load side of trailer?
I typically run less than 10% when temps are constant from morning cold start, but if the temp rises 20* by noon, I'll see a 9psi rise when starting at 80psi cold. Sometimes that's on the sun load side, sometimes not.

BTW, I have experimented with 70psi, 75psi and 80 psi. (70 is ok per weight and 15% margin with Mich LTX LTs). I have noted no difference in ride quality at 80psi, so I settled in there.

[dkottum]

"BTW, I have experimented with 70psi, 75psi and 80 psi. (70 is ok per weight and 15% margin with Mich LTX LTs). I have noted no difference in ride quality at 80psi, so I settled in there."

Rich, how are you measuring ride quality inside the trailer?

[BoldAdventure]

Originally Posted by CapriRacer

Don't forget the rule of thumb:

You want to see NO MORE than a 10% pressure build up.

If you see 15%, you need to fix that IMMEDIATELY - as in more pressure, a larger tire size, slowing down, etc.

If you are experiencing 10% to 15%, you DO have to fix it, but you don't have to do it right away.

Also, achieving a 10% pressure build up is NOT a goal. It is an indicator if something is wrong. This is NOT to say that everything is fine if you get less than 10% - It's that MORE than 10% is definitely a problem.

That seems to match my earlier statement:

Originally Posted by BoldAdventure

I thought I read somewhere from Tireman6 or whatever his name is, that a tire's PSI shouldn't increase more than 5-8psi. If it's increasing by 10 or more psi then it's underinflated, overinflated or overloaded.

Originally Posted by Alphonse

BA, how fast were you driving?

60 mph

Originally Posted by dznf0g

Do you need to account for ambient temperature rise when noting percent rise throughout the day? As well as sun load side of trailer?
I typically run less than 10% when temps are constant from morning cold start, but if the temp rises 20* by noon, I'll see a 9psi rise when starting at 80psi cold. Sometimes that's on the sun load side, sometimes not.

BTW, I have experimented with 70psi, 75psi and 80 psi. (70 is ok per weight and 15% margin with Mich LTX LTs). I have noted no difference in ride quality at 80psi, so I settled in there.

Temperature has to play a role. When we were in Moab, I had my tires on the truck deflated to 33psi. We drove up to the LaSal Mountains where it snowed, and as the temp dropped my warning lights for low pressure came on because the TPS was reading the tires at 29psi.

So I can only stab at the wind here, and assume that ambient and maybe even the temperature of the pavement plays a role.

[dznf0g]

From prior posts in other threads, ambient temp is about 1 psi difference for every 10* change...but I don't recall the discussion relative to pressure rise (10% max) with any reference to ambients. I do recall that pavement temp was not considered significant with a rolling tire and airflow around it.