Tire pressures

[shoregrass]

I have a 2020 Vista 29VE. The info plate on the wall near the driver's seat says that I should run my 19.5" Goodyear tires at 82 psi. The tire sidewall says that the max. load pressure for these tires is 110 psi. I have started running the tires at 86 psi. to get better gas mileage... maybe I could even run them harder? I know there are some factors here that I need to be aware of - like heat expansion in the summer and the fact that I don't want to shake this thing apart on poorer road surfaces. Even fully loaded according to the sidewall, I'm still under the max. individual carrying weight for the fronts or the duals in the back. I had it weighed on a scale.

Any thoughts?

 

[4x4van]

Ignore the number on the tire itself; it has no bearing to YOUR RV, it is only relevant to the maximum weight that the TIRE can support, and that tire can be (and is) used on more vehicles than you can count. The placard near the driver's door reflects the pressure needed for the maximum weight that your RV should ever see; in other words, fully loaded up to it's GVWR. Can you go higher psi? Yes, but your ride (as well as control) will likely suffer, and I doubt that you will ever see an actual measurable difference in mpg. Your best bet is to actually weigh your RV, loaded for camping (4 corner weigh is best, but at the very least, each axle), and then use the tire pressure charts for your tires and adjust your pressure accordingly. That will give you the best handling, wear, and control.

 

[BCam]

4x4van is correct but I'd like to expand on it a bit:

There are a lot of Winnieowners threads addressing the tire pressure issue. Rather than repeat what's already been posted I suggest you use the Google search box at the top of the page to search for "tire pressure" and read as much as you can. Pay particular attention to posts by Roger Marble who posts on Winnieowners as Tireman9. He's a retired tire engineer and is our resident expert.

In the meantime, inflate to your door placard pressures until you understand the process of weighing and using tire pressure tables. Note that, assuming you're not loaded to your rig's GVWR, the weight/table pressures will be less than those on the door placard and likely will give a more comfortable ride.

 

[Morich]

Agree that there is a tremendous amount of info and discussion of tire pressure but I've also come around to a bit different thinking, once I got Tire pressure monitors on all wheels. I am always a bit fussy about keeping air in the tires but now I look at it in a less critical way as I see it can never be exactly "right". It will always be a bit of compromise as well as some "windage" for different temperatures and conditions. You are not likely to really be loaded the same on every trip and the outside temperature and weather is certainly going to vary.
So I've stopped sweating it quite so much! Reason for that is that I can see what the pressure does at all times and it shows me that things like sunlight on one side, does give me a different pressure. Parked at the house, the tires shaded by the fence differ from the other side! Driving for twenty minutes on a hot day gets me a quite different tire pressure than on a cold day. The inner dual gets different loading, depending on the shape of the road! Until they figure a practical way to adjust the pressure as we drive and do it automatically, I'm never going to have the exact right pressure, so I go for the best I can do and call it a day.

 

[4x4van]

Agree that there is a tremendous amount of info and discussion of tire pressure but I've also come around to a bit different thinking, once I got Tire pressure monitors on all wheels. I am always a bit fussy about keeping air in the tires but now I look at it in a less critical way as I see it can never be exactly "right". It will always be a bit of compromise as well as some "windage" for different temperatures and conditions. You are not likely to really be loaded the same on every trip and the outside temperature and weather is certainly going to vary.
So I've stopped sweating it quite so much! Reason for that is that I can see what the pressure does at all times and it shows me that things like sunlight on one side, does give me a different pressure. Parked at the house, the tires shaded by the fence differ from the other side! Driving for twenty minutes on a hot day gets me a quite different tire pressure than on a cold day. The inner dual gets different loading, depending on the shape of the road! Until they figure a practical way to adjust the pressure as we drive and do it automatically, I'm never going to have the exact right pressure, so I go for the best I can do and call it a day.

Well said. I've weighed my RV once - 4 corner - and set the pressures on each axle accordingly. Haven't touched them since, other than to occasionally check to see if they've lost air (Manually since I don't have a TPMS). Will likely re-weigh every other year or so to make sure that I'm still in the same weight range, but I'm not too worried about "weight creep" since I am at the lower end of the weight range for the pressures I'm running. I do occasionally check temps with an infared temp gun while traveling, but I try not to overthink things.

 

[Morich]

I was simply amazed at how much the small things change the pressure. My info says 82 PSI for all six wheels and I was finding the dealership had them all at 120 for cold temps, so I started working the pressure down while adding the TPMS. Going slow until I found what really was needed and got it weighted but not wanting to let too much out and have to get out the compressor to add it back!
So as I let air out in the morning and found the pressure higher when I got back to it after lunch, I began to look at why! Nobody sneaking out there to add air, so where was it coming from or was the TPMS messing with my mind?
Turns out that the sun creeping higher on a cool day and it hitting the tires on one side and back was the cause of a big jump in pressure!
I quickly became less hyper about getting all the tire pressures set just right! Small questions come up like, "do I run the inner dual on the right lower because the tailpipe runs past it?"
Just not as simple as adding the "correct" pressure, is it?
Unless I want to stop every few miles to let some air out when I hit a stretch of bumpy road which makes the tires flex more and heat more. Do I stop and add some more air if I hit a rain shower that cools the tires?
I now run what I feel is about the right pressure, make sure they are never run on too low and stopped worry about getting it right!

 

[Reniram]

Interesting reading..I also have the 29VE and had the Crossfire tire equalizer system installed using the 82 psi.kit on the rear wheel duals.. The tires were inflated to the required pressure reflecting the Safe Yellow flag ...too much pressure changes it to Red and too little indicates Black...Air temperature was appx 65* On our first trip out I was interested if and how the tires change and after only 30 miles we stopped at the local Pilot truck stop for gas, both sides were in the Red..So it seems to me the tires are running between the low 82 psi and whatever the ambient / road temperature is affecting the high temp range.. so I have little actual imput maintaining a perfect pressure..in this case the tires increased 12 psi according to my air gauge so now I am running at 94 psi?..So the bottom line I suppose is maintain the psi when the tires are not in direct sun or not exposed to winter conditions..The tire manufacturer obviously takes all this into consideration when they advise min and max inflation rates knowing they could be used at minus 20* or +100* degrees..To be sure you need to replace them at the suggested time interval..and it would be up to us to make a visual inspection for tread wear or separation or sidewall damage to keep us safe on the highways...

 

[Morich]

In looking around for what might be best on tire pressure, I found a bit of info that is on the Winnebago site which gives me a bit more info and I thought might also be of interest to the group. I find there is way too much info available to read it all and this is one bit that I had skipped over many times but in reading it now, I may have spotted something that I might change in how I maintain my RVs.
Maintenance is almost always going to be a compromise between what is recommended and what we each find works best for us and this is certainly true when we look at our tires on RV.
Do a careful read of this item and see how it might change your routine:
https://winnebagoind.com/resources/service/pdfs/2016-11 Loading-Handling_and_Abnormal_Tire_Wear.pdf
It involves why it is recommended to have the alignment checked and adjusted after you get your new RV loaded. I have to admit that I have NEVER had one aligned, my excuse being that I have never had a problem with tire wear and assumed it was aligned correctly when built!
Seems that may be more a matter of load and luck than actual good practice!
The bottom line for me seems now to be that I do need to keep a critical watch on my
tires for any signs of unusual wear but how to react to what I find is still a bit of question in my case.
This is one that certainly varies, depending on how and what we each drive as a full time roadrunning guy may have a totally different plan than somebody like me who puts just a few thousand miles on a year. We each have to balance the time, expense and nuisance of what we spend on preventive work versus what it might save us on tire replacement. RV maintenance and things like tire alignment tend to be very expensive, so the question becomes how we want to deal with that problem. Do we spend several hundred dollars to save a set of $200 tires or are we looking at saving a set of $600 tires?
Or do we worry less as we know the tires will need to be replaced before the wear gets to them as we simply do not drive that much?
I'm in the "watch and wait" group as tire wear has never forced me to replace tires on any of the multiple motorhomes I've owned.

 

[David_Laura]

On the subject of tire pressures, what are the tolerances (plus/minus) on my recommented pressure of 70 psi based on the weight tables. For example if one set of duals are both 69.5 and the others are 70.5, is that okay?

 

[Wyatt-WO]

On the subject of tire pressures, what are the tolerances (plus/minus) on my recommented pressure of 70 psi based on the weight tables. For example if one set of duals are both 69.5 and the others are 70.5, is that okay?

I’d imagine that small variance is outside even the spec tolerance of your gauge. I think you’d be fine...

 

[JoeVac]

When we bought our 2002 30b the tire pressures were different on all tires. since then i have added new bilstein shocks, front and rear trac bars, roadmaster steering stabilizer, new sway bar bushings front and rear, and did the cheap handling fix. i played with tire pressures and coach was still all over the road. finally set all tires to 80 psi all around as stated on tire placard. Bingo,,ride improved and straight line tracking was so much better. I have found that to much pressure will cause wandering, at least in my case. My next thing to do is replace the spring eye bushings, they are starting to crack and hopefully they will limit a limit spring movement a bit..

 

[sundog964]

Some data from my latest trip in our Vista with a newly installed TireMinder.

Started the trip, CA to TX via I5 and I10 with all 6 tires inflated to 82 per the sticker in the cab. Both of the inner rears went up to 102 and 103 psi while the outer s remained about 98 psi. Fronts about 96 psi max.

Any idea why the inners would go 5 psi higher?

The TireMinder throws an over pressure at 98 when set at 82 cold

 

[Podivin]

Some data from my latest trip in our Vista with a newly installed TireMinder.

Started the trip, CA to TX via I5 and I10 with all 6 tires inflated to 82 per the sticker in the cab. Both of the inner rears went up to 102 and 103 psi while the outer s remained about 98 psi. Fronts about 96 psi max.

Any idea why the inners would go 5 psi higher?

The TireMinder throws an over pressure at 98 when set at 82 cold

Possibly due to less air flow on the inside dual than on the outside, plus just being closer to the hot running gear and exhaust.

 

[BCam]

Pretty much everything you want to know you can find here:

https://www.rvtiresafety.net/2011/03/introduction-to-this-blog-and-roger.html

The author, Roger Marble, aka Tireman9 is a Winnieowner and a retired tire engineer:

https://www.winnieowners.com/forums/members/tireman9-44688.html

Roger advises adding 10% to the recommended table values when inflating your tires as indicated in this item from his blog:

https://www.rvtiresafety.net/search/label/Critical temperature

 

[Morich]

The above plus there are crowns built into lots of highways to help drain water off the driving surface with the increased height of the inside making those tires carry slightly more weight and flex slightly more.
If you have one of the better TPMS systems that allow you to change all the alarm settings, you may find you need to adjust them several times to find what is right for your area and weather on different trips.

For practical, we found it hard to live with knowing what the tire pressure was set to as it was not working for middle of the country weather where temps vary a lot. Setting to the spec temp of 82 made us riding on 100 PSI and way to harsh most of the trips. Setting the alarms for low pressure made the alarm wake us in the early morning when temps and pressure dropped! Did not want a 4AM alarm telling me the tires were going flat just before sunrise.

We eventually dropped the tire pressure from 82 into the 70's to avoid driving on super hard tires. That left us going with pressure in the 80-85 range much of the time, starting at aobut 60 on cold days!
The point for me was that the tire pressure is rarely going to be "right" as per spec as each tire changes when the sun or road surface changes! My inside right dual always ran hotter and was next to the tailpipe!
While I always obsessed with setting the pressure right when not having a TPMS, I now see I was wasting my time as sunny side varied from shady side when driving or setting in storage!
It's an estimate of best practice and nature will change it as she feels! If you want to leave Chicago with the pressure just right, don't expect it to be right when you get to Houston!

 

[creativepart]

My RV placard says to set the tires at 100 psi front and rear. I weighed the coach, consulted the Michelin charts for my exact tires and set the pressure at 80 front and 85 rear. This did improve the ride some.

However, after about 20k miles my front tires looked horrible. The outer treads were worn badly and I had serious "rivering" wear showing, too. So, I took the RV to a truck tire alignment shop with a very knowledgeable tire professional. He showed me that the front "steer" tires don't have a lot of weight on them and the low pressure was making the wear worse. The tires were bouncing down the road. You couldn't feel it, but the cupping and rivering showed it.

We moved the two front tires to the left rear location and put the very sharp shouldered rears to the front. We did a full alignment and increased the PSI to 95 all around.

I only have 2500 miles on the new setup but everything is wearing great.

Semi-Truck tires are a major cost and serious problem area for trucking companies. Trucking companies and owner operators are willing to spend for good alignments and good tire advice and services. So, finding a popular and successful tire shop that caters to semi-trucks is an eye-opening experience. I learned a lot.

My tires will be 5 years old in July 2022 and I plan on replacing them then. By the way, the previously mentioned Tireman9 looked at my photos and he agreed with everything said by the tire shop owner and agreed that the front tires didn't need replacing - just moved.

Here's my front tires at 38,000 miles that got me to make changes:

 

[DesertRatt-WO]

2004 E450 Class C 30'

When i bought it i put 6 new Michelin XPS RIBs on it. The tire shop inflated them to about 100 PSI. It was like driving a buckboard, only worse.

I then weighed it, got the Michelin tire table, and reduced the pressure to 55F, 65R and the ride is absolutely fabulous. I only have 6k miles on the tires but they wear looks negligible.