Tire pressure

[MrT]

Do I have to keep my tires at 82 psi or can it be lowered to get a smoother ride ? We are very weight conscious so I am thinking that it would be OK to lower the pressure. We have a Thor 29m Windsport. Is there a way to smother ride ?

[Scubawise]

I follow the yellow driver sticker

[EA37TS]

Weight the coach and set the tires to the manufacturers recommended pressure. Thousands of posts about this topic. Use the search feature

[chunker21]

Originally Posted by EA37TS

Weight the coach and set the tires to the manufacturers recommended pressure. Thousands of posts about this topic. Use the search feature

Yes absolutely positively weigh the coach and get side weights if possible. I've explained that in the past but will again. Many CAT scales have room that will let you park 1/2 the RV on the scales but get different axles on different platforms on the scales. The second weighing is usually $5-7 if done at the same visit. If CAT isn't anywhere close, call a moving company, etc. and see if they will accommodate you. All tires on the same axle should be the same PSI. The yellow sticker put in by thor just references the maximum PSI for the tires carrying the maximum rated load and has nothing to do what the actual coach weighs or desired tire pressure.

Until you weigh the RV you are guessing at proper tire pressures.

[Jimbo56]

If you’re at 82 psi for that coach the tire pressure is not the problem.

Please define your definition of the ride you’re experiencing and what you would then like it to be. Remember, your coach is built on a truck chassis.

Also what year is your 29 ?

[MrT]

Thank you, I will get my RV on a scale. The landscape and gravel co near me said they would let me weigh the RV on their scale. I hope that will work.

[Beau388]

Originally Posted by MrT

Do I have to keep my tires at 82 psi or can it be lowered to get a smoother ride ? We are very weight conscious so I am thinking that it would be OK to lower the pressure. We have a Thor 29m Windsport. Is there a way to smother ride ?

The 82 psi is the lowest safe pressure for all your 6 tires if the coach is fully loaded to the 18,000 chassis weight. If you load the coach for travel and have each corner weighted, then some tire pressures may safely be able to be lowered.

My coach is on the Ford 18,000 lbs F-53 chassis like yours. After weighing my coach, I found I could safely lower the front tires' air pressure to 75 psi (cold). Watching the TPMS pressures, the pressure gain was less than 20 psi so I new I was safe. With the 4 rear tires, I decided to raise the pressures slightly to 88 psi even with the rear corners at 5860, 5780 lbs on the 12,000 lbs rear axle. This was because with 82 psi (cold) in the tires, the tire pressure gain was in the 24 psi range. With the 88 psi in the rear the tire pressure gain is now down to 19 psi.
The tires gain pressure when on the road is due to flexing (tires are flat on the bottom and round elsewhere). In creasing the pressure lessens the flexing. The less the tires flex the lower the temperature gain. Speed also effects pressure gain as the tire has less time to cool (shed heat) with more speed. High road temperatures can also effect tire pressure gain.

[MrT]

It is a 2017 Thor 29m.
The first 6in of the awning from the RV is starting to get some signs of UV damage. I am thinking of using some 4in Flex Seal tape to cover this aria. Replacing the awning is expensive.

[waynetaylor55]

Originally Posted by MrT

It is a 2017 Thor 29m.
The first 6in of the awning from the RV is starting to get some signs of UV damage. I am thinking of using some 4in Flex Seal tape to cover this aria. Replacing the awning is expensive.

[chunker21]

Originally Posted by MrT

Thank you, I will get my RV on a scale. The landscape and gravel co near me said they would let me weigh the RV on their scale. I hope that will work.

Yes if they have scales with more than one section. At a minimum you need axle weights. If they only have one platform them you can get very close by multiple weighs. Front, rear, side etc. Try to weigh with the load you travel, fuel, water, etc.
Congrats on making the effort to get knowledgeable with your RV.

[MrT]

The scale is large enough to drive the RV.onto. I may try to put just the front tires on, then all 4 are on and then pull forward so that just the rear tires are on the scale.
Hopefully that should give me 3 readings. Maybe this will help me to adjust the right TP for RV. Thanks for your help.

[chunker21]

Originally Posted by MrT

The scale is large enough to drive the RV.onto. I may try to put just the front tires on, then all 4 are on and then pull forward so that just the rear tires are on the scale.
Hopefully that should give me 3 readings. Maybe this will help me to adjust the right TP for RV. Thanks for your help.

Sounds like you might be able to weigh a side also. If so I's encourage that since you will be already there. An example my 40'DP was 700# heavier on the right side which surprised me. I've read other example of significant differences. My last 5th wheel toy hauler was less than 50# difference and based on where the appliances were, expected a greater difference. Couldn't get the Omni 1/2 on due to changes at those scales.

[dkoldman]

Originally Posted by MrT

Do I have to keep my tires at 82 psi No; or can it be lowered to get a smoother ride ? Yes We are very weight conscious so I am thinking that it would be OK to lower the pressure. We have a Thor 29m Windsport. Is there a way to smother ride ?

There are lots of ways to a smoother ride than the factory chassis, but you are really asking about tire pressure.

Putting stock in your statement "We are very weight conscious" You don't need to get a weight, but for some it seem like the essential and only thing to do? I agree it is the one catch all correct answer that can apply for everyone's situation, but for most people; they never exceed the weights provided by the yellow sticker. And if they do, they know it ahead by what they are towing and by what they are loading maybe full time RVer, moving someone and / or equipment etc.

With that out of the way while yes you can lower the tire pressure; but by how much should have been the question? You need the Tire Mfg, Tire Specs and yes the tire weight (directionally that is)

For example, I have a 29' RV as well. with Goodyear G670s 245/70R 19.5, the yellow sticker says 82 psi for all 6 tires. I have never weighed and prolly never will unless stuck at a Loves without nothing else to do, and I have some money that I don't need for gas to throw away

But anyway, for my tires per Goodyear G670s tires made after 2/28/06; the absolute lowest safe tire pressure for ANY RV is 80 psi. When I set at 82 psi per yellow sticker the random and inherent variation may get me 81 psi or 83 psi anyway. If someone tell me that dropping 1 psi to 80 is going to get me a smoother ride, I am going to say I don't believe it because when driving I am quickly up to 93 psi or higher anyway

Note: Even if you chose to be weight conscious, you would need to weigh at the beginning of every trip to accurately account for variability of water, fuel holding tanks etc (let along personal belongings), which can easily be 500 pounds of change mid trip which would theoretically mean that you would need to stop during the trip to release or add air

[MrT]

R U trying to tell me there are other ways to get a better ride from this truck chassis. I am all ears.

[dkoldman]

Originally Posted by MrT

R U trying to tell me there are other ways to get a better ride from this truck chassis. I am all ears.

Yes, but you have started with the correct 1st step. It is like a hearing loss, checking for wax is very important; but for most it is not The Solution.

The below is my humble opinion, I don't claim to be an expert, but open to any countering views based on material facts and not emotion.

1. Verify proper air pressure on all tires
2. Define & verify your expectations; no matter what you do, it will still be a truck with a house on top of it.
3. Stabilize the front - Safe T Plus or similar (Roadmaster etc.) I chose Safe T Plus as it was recommended by my Dealer and my RV Mfg. A call to Ford even supported this upgrade.
4. Sumo Springs - Expensive; overpriced but it gets rid of 95% of the rock and roll. Out of all my upgrades it is the one that I have done that I complain about having to do the most; it definitely was needed; but $1,300 for the parts? Labor was $600 more; but given the job, I thought the labor cost was fair.
5. New Shock Absorbers - I have not done this one yet, but if I continue my current rate of no out of pocket repairs, I will use my year 3 money saved from not buying an extended warranty to buy 4 new shocks, don't know which ones yet? I have $1,500/year set aside for repairs or upgrades when repairs were not needed

Also, I have been going to Discount Tire forever, I was there last week buying new tires for my wife's car, the Manager told me they now work on and service RVs with 19.5 tires or smaller ( I had asked him about it a year ago and he remembered Not that I will use them for repairs, but they can check the tires, make sure they are properly inflated etc. Or you can do what I have done and that is go to a Goodyear Tire & Truck Center, make friends and get all the information you need to know ( I assume you have Goodyear tires). People that care appreciate being appreciated. They sold me a brand new G670 with a 3 month old DOT mfg code retailing at $550 tire for $140 They cited some unpublished clearance promotion. I bought it for a spare tire with no wheel, I put it under my bed, but it is heavy, I can't imagine trying to pick it up with a wheel


If you have Goodyear this is the Guide I use.
https://www.goodyearrvtires.com/pdfs...care-guide.pdf

Good Luck

[Beau388]

Originally Posted by dkoldman

There are lots of ways to a smoother ride than the factory chassis, but you are really asking about tire pressure. [snip]
For example, I have a 29' RV as well. with Goodyear G670s 245/70R 19.5, the yellow sticker says 82 psi for all 6 tires. I have never weighed and prolly never will unless stuck at a Loves without nothing else to do, and I have some money that I don't need for gas to throw away [snip]

To set your mind at ease, I wore out the Goodyears in 2020 and switched to Sumitomo ST718 from Walmart. Most feed-mills, auto recyclers and gravel sellers will usually weigh your RV free. Call first to find a slack time.

[dkoldman]

Originally Posted by Beau388

To set your mind at ease, I wore out the Goodyears in 2020 and switched to Sumitomo ST718 from Walmart. Most feed-mills, auto recyclers and gravel sellers will usually weigh your RV free. Call first to find a slack time.

How long did your Goodyear's last? Mine are 2 years old with 16,000 miles with no signs of wear, they actually still look new if you looking at the threads.

I bought another Goodyear G670 as a spare so that if I ever have an issue and have to call roadside, when they put that tire on, it is done, I don't have to worry about changing back out later when I am safely at home. I am a tire fanatic and do not like having mismatched tires.

Usually unless I personally experience an issue with OEM tires, or they don't last long enough, I will always go with the same OEM tires. Ironically, I had an exception to that last week. My wife has XT5 that came with Michelins, although the tread life was still good, both front tires looked like she had been driving over a barbed wired road It wasn't just a wear pattern, I saw physical separations; I thought she had run over something? Discount tire said maybe they needed rotating more? Anyway the exact same tire was NOT available (prolly for good reason...), so I went with the same OEM Pirelli that came with my Navigator SUV that fits her car as I love the Pirelli All Season Scorpions. They ride smooth.

Akin to why I will NEVER take the time to put water in FLA batteries, I don't see myself driving my RV to any feed-mills, auto recyclers nor gravel sellers. To what value? Per my tire mfg, for a mere 250 pounds of weight difference on the fronts or rear duals; I would adjust my tire by 10 psi. I have 70 gallon water tank. So just talking water alone, when I leave on any trip that is 581 pounds of fresh water, when my fresh water tank is at half full I am now 290 pounds lighter; I don't need another weigh to know that; nor do I have any intentions of trying to reduce the air pressure by 10 psi when returning; nor adding 10 psi when I fill the tank again. Throw in the other impacts of gas, holding tanks, fewer bottles of beer on the return trip and to me the weighing thing is just nuts unless you know you have a heavy load. For example if I knew I had 40 gold bars to carry home with me, I would add to tire pressure to around 95 psi, if I had 80 gold bars I would go to 110 psi. More than 80 gold bars; I start chunking things maybe even the DW (temporarily) But you know what, going to get a weigh would be the last thing on my mind

But to the point and question of OP, none of the above weighing is going to make his ride smoother to which he seeks. He is NOT overweight and he is within correct specifications. He wants better. (smoother ride) At 82 psi, he may not be able to go much lower than that when underweight. In my case, per Goodyear, I could technically go down to 80 psi and be per their minimum specifications; but I don't. I stay at 82 psi.

[Lt Keefer]

I agree that lowering air pressure can improve the ride but also agree that there is not that much difference from 82 to 80. When I picked up my coach new, Camping World had the tires set to 105 and it was all over the road. When I got to my first stop, I dropped the pressures to 80 and it drove great to my final destination. The next morning I set them to the sticker's 82. After weighing the coach, I lowered them to 80 and have been at that pressure ever since. The real difference in smoothing the ride was the sumo springs. They were easy to install and the coach rides a lot better. The CHF and steering damper may have aided but if so, it was minimal.

[Luke D]

Originally Posted by MrT

Do I have e propto keep my tires at 82 psi or can it be lowered to get a smoother ride ? We are very weight conscious so I am thinking that it would be OK to lower the pressure. We have a Thor 29m Windsport. Is there a way to smother ride ?

Not sure why 82 PSI works. Goodyear and Cooper manufacturers say that the proper tire pressure for a motorhomes on the Ford F53 chassis and Ford V-10, 29 ft or over requires 90 ft and 95 to 100 rear PsI . Never understood the 82 PSI , the lower inflation on 14 or over ply tires caused tire roll and inner and outer premature tread wear. I guess there’s several different psi thoughts out there. So go with what works for you

[dkoldman]

Originally Posted by Luke D

Not sure why 82 PSI works. Goodyear and Cooper manufacturers say that the proper tire pressure for a motorhomes on the Ford F53 chassis and Ford V-10, 29 ft or over requires 90 ft and 95 to 100 rear PsI . Never understood the 82 PSI , the lower inflation on 14 or over ply tires caused tire roll and inner and outer premature tread wear. I guess there’s several different psi thoughts out there. So go with what works for you

Can you reference where Goodyear says "that the proper tire pressure for a motorhomes on the Ford F53 chassis and Ford V-10, 29 ft or over requires 90 ft and 95 to 100 rear PsI . "?

82 psi works for me because my ride is smoother compared to when I had it at 85 or 90 just playing around. If it is was 81 or 80 when I checked, I would not bother to add air.

Now I can't speak ANYTHING to Cooper, but for Goodyear I have never seen them state what the tire pressure should be based on Chassis alone? I don't doubt it could exist, but if it does it is all predicated on the weight on the axles & tires. There are known standard weight ratings; so it is easy to draw a conclusion based on assumptions without technically getting the exact weight.

But the below is the Goodyear RV Tire Guide. Some tires are rated to go down to 70 psi and lower. My tires the G670 245/R70 19.5 should never be lower than than 80 psi and there is no need to EVER go higher than 82 psi; unless I am going to add something that far exceed my standard weight rating on my yellow sticker. I never do and I never will, thus I have no need to ever weigh; short the one day I may do just due to the curiosity factor; NOT that I expect to suddenly have a smoother ride on the F-53 Chassis

https://www.goodyearrvtires.com/pdfs...care-guide.pdf