LT G-Rated Tires

[johnam1]

At the suggestion of an RV dealer (name withheld) They replaced the 235-80-16 ST West Lake Tires (after a blow out and tread separation) with Hercules 901 238/85/16 LT tires.
They mounted them on the existing 16X6 rims rated at 110 PSI. The technician stated to keep the tire pressure at the Vilano's manufacture's posted label pressure of 80 PSI., not the tires pressure indication of 110 PSI.
After further research it appears that I should replace the rims with 16x6.5" high strength rims with high pressure metal valve stems.
Note the load weight on each tire is 3200 pounds.
Am I correct? Any suggestions?

[Cummins12V98]

GordonThree wrote:
Scale the weight and then look up correct pressure from manf tire load table. Too much pressure can be bad for the tire too.

Per GY Tech add 5psi to the required number to carry the load. This is when up sizing the load range. I did the same E-G and ran 85psi. Perfect tire wear after many thousands of miles along with a nice ride.

[neil57]

I agree with Gordonthree, need to match pressure to load.
The sidewall is max pressure, max load of 3750 lb. At 80lbs. Inflation chart shows 3042 capacity. A pressure of 90psi would give 3300 lb load carrying capacity according to chart.

[JIMNLIN]

The technician stated to keep the tire pressure at the Vilano's manufacture's posted label pressure of 80 PSI., not the tires pressure indication of 110 PSI.

Very bad advice. Were talking tires used in a trailer with close spaced axles which have different pressure needs than the tow vehicle with tires at the corners.
The trailers tires side scrubb (twisting) as its pulled around corner or backing up maneuvers. Max pressures help hold the tires normal shape and fight interply shear and makes a cooler running tire.

Tire experts.....tire safety blogs....even tire mfg recommend max sidewall pressures for tires used in a trailer position unlike tires on our trucks.

Now if the trailer has been severally over tired then at some point max pressures would be too much.

If thats the case then I like this from;
rvsafety.com

Tire Load and Inflation Ratings

Note: Towable – Travel Trailer/ 5th Wheel owners Due to the severe use conditions experienced by tires when axles are very close together – tire industry experts recommend maximum (sidewall) inflation pressure for towable tires unless this causes a sever over-inflation situation (20psi+), often referred to as the ‘basketball effect’. If this is your situation allow a 10 – 15psi safety margin above the minimum required inflation pressure.

And rvtiresafety.com (Tireman9 on several rv websites);

**When not driving in a straight line there are special side loads on multi-axle trailers because the tires are fighting each other because they are not "pointed" to the center of the radius of the turn. These loads cause interior structural tearing. Sometimes 24% higher loads than those seen in tires on non-trailer application. Initially tearing is at the microscopic level but with time and repeated cycles these forces grow which can lead to small cracks at the belt edges as seen here at the arrows.
and
You can lower these forces by either decreasing the load 24% on the tire (probably not something you want to do or may not be able to do) or you can increase the inflation to stiffen the structure and decrease the slip-angle. In this case you could increase the tire inflation from the minimum inflation needed for the static load to the inflation associated with the max tire load as molded on the tire sidewall**.

[rhagfo]

johnam1 wrote:
At the suggestion of an RV dealer (name withheld) They replaced the 235-80-16 ST West Lake Tires (after a blow out and tread separation) with Hercules 901 238/85/16 LT tires.
They mounted them on the existing 16X6 rims rated at 110 PSI. The technician stated to keep the tire pressure at the Vilano's manufacture's posted label pressure of 80 PSI., not the tires pressure indication of 110 PSI.
After further research it appears that I should replace the rims with 16x6.5" high strength rims with high pressure metal valve stems.
Note the load weight on each tire is 3200 pounds.
Am I correct? Any suggestions?

Well based on this information the tire will carry 3,756# each, you state 3,200# per tire load, so based on four tires that would be about 2,224# of extra capacity at 110 psi, I would air to 90 to 100 psi, for the best road contact.

[NHIrish]

If you went to G rated tires to take advantage of their added carrying capacity, you are not getting that at 80 psi...although you are likely better off than you were because of the more robust build of the tire.

For my money, I would air them to 110 to take full advantage of the increased load rating...which is the reason you did this in the first-place.

If your rims are rated for 110 psi you are good but will need metal hp valve stems.

Some will argue that you need to weigh all wheels and air them according to weight and psi charts.

Neither is wrong, but one is a lot easier than the other. Road forces are hard to predict, and I like all the extra capacity I can get. The argument against automatically going to 110 psi is that it increases the harshness of the ride...which is not an issue in my mind.

[MrWizard]

moved from technology
technology is for
"the wired Rv member" aka electronics, phones, gps, computer

[GordonThree]

Scale the weight and then look up correct pressure from manf tire load table. Too much pressure can be bad for the tire too.

[Home_Skillet]

Tech is correct.
You always go off the vehicle manufacturer's suggested pressures.

[ScottG]

Tech is wrong, I would air them up to the max because of how much weight they're carrying.
At 80 psi, they are probably over-loaded.

[donn0128]

Not knowing your RV particulars, but looking at your tires, I think you would have been better off switching to 17.5 inch size.

[Lwiddis]

Follow a tire installer’s recommendation or the manufacturer’s recommendations? Not a hard choice for me...manufacturer. And never exceed any wheel manufacturer’s limitations such psi and weight.