Goodyear G114 tire pressure question

[cwall59]

I have a triple axle 5thwheel with Goodyear G114 215/75R17.5 on it . I just weighed and I’m running at 18780 axle weight and 4180 pin weight. Do you add both weights and divide by six to get the correct air pressure on the chart . Or do you just go by axle weight divided by six ? I’m running about 117 psi and want to make sure I’m good ,125 psi is max pressure on the tires . I’ve heard these tires can run a little lower than max and you will get a better ride as long as the weight is correct.

[mjdenn]

Take the trailer weight and divide by 6. That yields 3130 per tire. The weights will not be even side to side due to the kitchen or other heavy components. If the trailer is not level the front to back weights will also vary. Add a cushion to allow for the weight variation and use a load chart for the tire. This should work for all tires.

[TXiceman]

The weight the tires are carrying is the weight on the axles. The truck is carrying the pin weight. Actually you need to get the weight of each tire and see which one is loaded the highest and use that weight to set all six tire with a cushion of a few PSIG extra.

Ken

[cwall59]

So looking at the chart the lowest pressure allowed is 90 at a weight of 3450 . If I went with axle weight divided by six that’s 3130 , add another 10% I’m still around the 90psi . If I go with the total weight of trailer I’ll say 23 k divided by six is 3833 . If I add 10% that’s 4216 that puts it in the 110 -115 range . I’ve been running around 116 so I think I should be good.

[cwall59]

Here’s the chart for my tires.

[mjdenn]

It's not the weight of the trailer as the pin weight is in the bed of the truck.
If you run 100 PSI to start and monitor the tread wear you should be good to go.

[Old-Biscuit]

Trailer AXLE weight is carried by the tires
100# each tire

Then take some Sidewalk Chalk ---big stick
Make a chalk mark across each tire side to side

Drive straight forward on asphalt for 25'
Then look at the chalk marks

Rubbed off in center...too high pressure
Rubbed off on edges....too low pressure
Rubbed off evenly across the thread....good pressure

[wandering1]

What does the PSI on the sidewall tell you????

[FastEagle]

Originally Posted by cwall59

I have a triple axle 5thwheel with Goodyear G114 215/75R17.5 on it . I just weighed and I’m running at 18780 axle weight and 4180 pin weight. Do you add both weights and divide by six to get the correct air pressure on the chart . Or do you just go by axle weight divided by six ? I’m running about 117 psi and want to make sure I’m good ,125 psi is max pressure on the tires . I’ve heard these tires can run a little lower than max and you will get a better ride as long as the weight is correct.

Are they original equipment tires?

[cwall59]

125 max

[cwall59]

Originally Posted by FastEagle

Are they original equipment tires?

Yes they are original.

[cwall59]

Originally Posted by wandering1

What does the PSI on the sidewall tell you????

125 max is on the sidewall . When I picked up my trailer it had around 115-117 in the tires . Of course it didn’t have anything in it but about 20 gallons of fresh water in the tank . Two 40 gallons propane tanks were full . It’s a rear kitchen model and the generator is located behind the rear axle. So most of the weight is on the axles . Paperwork for the tires suggested a tire pressure range of 105 -110 but it depends on how you load it . My max weight is listed as 26500 on the trailer. I’m pretty close to where I will be running and I’m a little under 23000 loaded .

[Old-Biscuit]

18780 axle weight divided by 6 = 3130# each

100# then check thread pattern with the chalk


Simpe.............

[FastEagle]

Originally Posted by cwall59

Yes they are original.

No one likes to play by the rules for RV trailer tires so I can only tell you the way it's supposed to be done.

All of NHTSAs publications are going to tell you that the correct inflation pressures for OE tires is found on the vehicle certification label, the load and inflation placard and in the vehicle owner's manual.

The U.S. tire manufacturers association (USTMA) says to NEVER use less inflation pressures than what has been recommended by the vehicle manufacturer.

The authority used to install OE tires on RV trailers is FMVSS. They give specific information to trailer manufacturers for the fitment of tires on the trailer and to insure the recommended cold inflation pressures for those tires are appropriate for that fitment. Therefore, the vehicle manufacturers recommendations are minimum recommendations.

Inflating RV trailer tires to the load carried IS NOT an acceptable option. That procedure is used by the trucking industry and is authorized as a standard within their regulations (FMCSA).

The tire industry does not SET RECOMMENDED COLD INFLATION PRESSURES. That is the sole responsibility of the vehicle manufacturer.

Remember, trailer manufacturers are not required to provide load capacity reserves with their OE tire fitments, unless they deem it appropriate, or they are following recommendations from another organization such as RVIA.