Tire Pressure

[GearyB]

I just bought a 2011 Tour 42QD. I need some advice on tire pressures. The dealer put all tires at 120. I can't get to a weigh station for awhile so I need preliminary pressures all around. Any Tour owners out there: what do you run?

[Robi.1014]

105 in each tire is my unprofessional opinion. My rig is VERY new to me, but I'm good with this amount until I can get weighed.

[akcretired]

115 in my 2015 Tour 42HD. Weighed out and nice ride

[Ray,IN]

Originally Posted by GearyB

I just bought a 2011 Tour 42QD. I need some advice on tire pressures. The dealer put all tires at 120. I can't get to a weigh station for awhile so I need preliminary pressures all around. Any Tour owners out there: what do you run?

All tire mfgrs. say to never run less air pressure than what is listed on the federal tire pressure placard in/on the vehicle_IF you are running the original size tires.

[PropFan]

If you are running OEM tires, why would you not go with exactly the cold pressure recommend on the label on the driver's side pillar? For example, my Sprinter manual says:

"The Tire and Loading Information placard contains recommended tire pressures for cold tires. Recommended tire pressures are valid for the maximum permissible load and up to the maximum permissible speed of the
vehicle."

That seems pretty definitive. In my case, that's 61 pounds.

[Mr_D]

Safest is to go by the Federal Tire Pressure label. That's what CC says in their owners manual and what my TPMS is set for. That means 125 fronts and 105 drive and tag for my rig.

[jadatis]

I am able to calculate an advice for you .
Once you weighed ( best per wheel(pair), second best per Axle), the advice will be saver, but as long as you did not do that , we have to go from the data you can get from vehicle and tires. Then we assume you drive fully loaded ( not bad idea for a motorhome or Travel-Trailer) and not overloaded on any axle.

For this I need from vehicle next.
1: configuration: front and rear number of axles and number of tires on the seperate axles ( if tag-axle also give and where its placed ).
2:GAWR( gross axle weight ratings) for every axle, can be found on the same plate as the pressure advices mostly.
3: Speed you use and wont go over for even a minute ( so be honnest).
4: also handy is the GVWR ( gross vehicle weight rating, so max allowed total weight of vehicle)

From tires I need next, and can be read from the sidewall:
Mostly all around the same tires, but can be different , check this)
1: Maximum load or Loadindex ( for single and Dual load).
2: Loadrating to determine the pressure behind AT ( yours probably 120 psi = H-load LRH, but also sometimes J-load AT 125psi)
2A: you can also read from tire something like this "maximum load ( single/Dual) xxxx lbs/kg AT YYY PSI( cold)".
3: speedcode of tire ( yours probably L ( max 120km/75m/h)or M(max130km/81m/h)

You can find this all now without weighing, so give that and I will give a presssure range in wich tires dont overheat , and comfort and gripp is still acceptable.

[Lv2Roam2]

On my '15 Ellipse (Tour's sister) - with four corner weights - the Freightliner Service Center set the pressures as:
- Steer = 120# (295s) I can go to 115# but there's no ride difference and I like the safety margin.
- Drive and Tag = 90# (275s)

BEST option is to do a 4-corner weight fully loaded with 'stuff' and full fuel / fresh water. Its just as important to see differences in weights across the axles as the gross axle weight so you can either rebalance or set pressures for maximum weight. If you have Michelin tires their tire pressure charts are the 'go-to' reference.

I back up all this with a good TPMS. Safe travels ...

[wildtoad]

Until you get real weight data, use what's on the placard.

What's interesting is when the placard has a significantly higher pressure than what the OEM tire manufacturer states for the unit, using the GAWR's.

[powercat_ras]

I would use what Winnebago put on the sticker, increased by 10 percent. Down side to the higher pressures is slightly rougher ride. Up side is your tires will wear less at the higher pressure and if they slowly leak down you won't go below the sticker pressure. You NEVER want to be below the sticker pressure this causes higher tire wear and if a lot below the sticker your tires will overheat and fail.

[FastEagle]

Originally Posted by Ray,IN

All tire mfgrs. say to never run less air pressure than what is listed on the federal tire pressure placard in/on the vehicle_IF you are running the original size tires.

X2!

[Ron Postma]

Don't go above 120 psi this is the max air pressure of the tires. I run 115 steer 95 in the drive and 90 in the tag. If you run 120 in all tires you will not have any issues but the ride will be rough. I just went to Camp Freightliner and they say weigh your coach calculate the manufacturers pressure and add 10psi to the rear and 5psi to the front. As stated by Freightliner the placard is put at the max pressure because Freightliner does not know what the coach builder will put on the chassis. Freightliner is the one who puts the placard on not the chassis builder.

[Ron Postma]

Here is the charts for the stock tires. The ones in yellow highlight. The top is the tag and drive, and the third from the top is the steer.

[toddb]

I run 115 front. 95 Main and 100 tag. Seems to work for me.

One thing you will want to do is definitely check the axle weights. Pay attention to the weight on the tag as it directly impacts the weight on the other axles. When we first got our rig there was way to much weight on the tag. Like 9000 lbs. This does 2 things, it throws (adds) weight to the front axle and takes weight off the mains. You are going to find that the 2011 42QD has a lot of weight up front, (that 10K Onan is not light!) not much margin wrt axle weight/tire pressure so 115-120 should be what you need to run upfront. You definitely have more margin on the mains and tag to run lower than 120PSI.

Long ago, I made an appointment with the Freightliner dealer in Brooks Oregon and cycled back and forth between them and the nearby certified CAT scales at Pilot a few times until I was happy with the front/main/tag weight distribution. I had previously weighed the coach and was running 14.8K Front, 14.7K Main, 9.0K Tag. After FTL tag adjustment I was at 13.4K Front, 18.1K main, 6.3K Tag.

[1doodadd]

The first thing I would do it Fill the Fuel tank, Fill the water tank, and take the coach down to a local certified truck scale and Get the Axle Weights, and total weight. Then you will know just what you are dealing with for Tire Inflations to cover your axle weights. You can always cover for the worst by running what the dealer inflated them at, but I have found 10 psi in certain manufactures make a Big difference in the ride and wear. Summer is coming and under inflated tires flex more and develop heat causing blowouts.

[mport68]

I had my 2012 42DQ Tour weighed at each of the 6 tire locations (both sides - front, rear, tag) and then set pressure according to the original tire manufacturers specification. All of this data is available on the Michelin web site. On my coach, it worked out that I need 115 psi up front, 95 at the rear and 85 at the tag. I choose to run 115-118 front and ~95-100 at all rear tires.

If you do not know your coach weight then run what the placard says but it is foolish to not have it weighed. At a minimum go to a truck stop and weight the front axle, real assembly (all 6 tires), and total weight. Then assume one side is 55%-60% the total weight given. and get pressure for your brand of tire from the manufacturer.

It's not only safer to run the correct pressure, it is almost always less than the max inflation pressure given on the placard so the ride is smoother. It is also a really wise investment to add a tire pressure/temperature monitoring system. get one for an 18 wheeler so you can include a trailer or car. You could tow a long way with a trailer flat and not even know it.

[CaptBud]

Had a 2011 Tour QD. Weighed at Freightliner in Gaffney, SC and they put 110 in the front and 90 in all rear. That was our coach with full everything(water,fuel etc)

[wildtoad]

Originally Posted by Ray,IN

All tire mfgrs. say to never run less air pressure than what is listed on the federal tire pressure placard in/on the vehicle_IF you are running the original size tires.

Not doubting you've seen this somewhere, but I've never seen this in relation to RV's. Could you provide a link that shows this? If true then 95% of people would never need to weigh their units. Yet both the RV manufacturer and tire manufacturer state to get the thing weighed and set pressures according to the tire pressure charts.

In my case, the placard shows a REAR pressure thats about 12lbs over what Goodyear says is required for the GAWR.

[TarasParents]

When our Forza was new and all our equipment loaded and half tank of H2O I called truck repair shops and found one that had portable scales.

[FastEagle]

Originally Posted by wildtoad

In my case, the placard shows a REAR pressure thats about 12lbs over what Goodyear says is required for the GAWR.

That's because the vehicle was built using the safety standards required by FMVSS which require a percentage of load capacity reserves.

Many of the posters recommending inflation pressures for "the load carried" are quoting out of context or quoting from FMCSA regulations which are for truckers and are not applicable for vehicles built to FMVSS standards.

If your vehicle has a certification label with vehicle manufacturer recommended inflation pressures it cannot be from FMCSA regulations because they have no such requirement.