Motorhome weighed - Tire Pressure to set

[kmb1966]

Could someone double check me on my air pressure? I could not find a weigh station to weigh all 4 corners, but I do have front and rear weights so far. Loaded the RV for travel.
Front: 6,540 lbs
Rear: 12,200 lbs
Total: 18,740 lbs

Tires are 245/70 19.5 14 Ply.
Hercules tire says maximum pressure 110 lbs. But they only show inflation table for 110 psi. Shows same carrying weights on the Single and Dual as the Goodyear G670 table.

I am putting 95 lbs on all 6 tires.

[stripit]

4x4van wrote:

timmac wrote:

I don't know why people say you need to weight 4 corners, just load RV even on all sides and just weight the front and back axels, that is all that is needed..

I call BS on weighting 4 corners, not needed unless your motorhome is leaning for some reason..

100% untrue. Very few if any RV's are evenly weighted side to side. While the difference may not be enough to dictate different tire pressures, oftentimes it is. My RV is nearly 1000# heavier on the driver side, due to bedroom slide and kitchen slide both being on the driver side, resulting in a 53.5/46.5 weight bias. The weight bias is built into the coach, yet it does not lean. Assuming anything about an RV's weight results in over or under pressure in your tires.

When I was weighing rv's with drive on scales it was not uncommon to find motorhomes with as much as 1.800lbs difference from side to side loaded full time rigs. Even brand new rigs sitting on the dealers lots had as much as 800 lbs spread from side to side without one item added by the new owners. Knowing those numbers is important to know what tire pressures are needed instead of guessing. You could guess wrong.

[4x4van]

blazenpm wrote:
Check your motorhome specs. I just learned not to go by what is printed on the tire, but what the motorhome manufacture recommends for your GVWR and the max wt. per front tires and rear tires. I was going to put 100 lbs. in mine then I looked on the manuf. recommendations and it was 75 lbs. for the front and 65 lbs. for the rear ( I have duel tires in the rear). This will potentially prolong the wear on your tires.

You are correct to not go with the pressure listed on the tire itself, but going instead with the RV's door tag is ONLY correct if the RV is at it's maximum allowable GAWRs and running the stock size/load range tires. Since the OP has in fact weighed his coach, the door tag is irrelevant.

[4x4van]

kmb1966 wrote:
Could someone double check me on my air pressure? I could not find a weigh station to weigh all 4 corners, but I do have front and rear weights so far. Loaded the RV for travel.
Front: 6,540 lbs
Rear: 12,200 lbs
Total: 18,740 lbs

Tires are 245/70 19.5 14 Ply.
Hercules tire says maximum pressure 110 lbs. But they only show inflation table for 110 psi. Shows same carrying weights on the Single and Dual as the Goodyear G670 table.

I am putting 95 lbs on all 6 tires.

Both Hercules and Goodyear agree that the 245/70R19.5 LRG will support 3640 single, 3415 dual at 80psi. Even if you use a 55/45 bias (the highest I've ever seen), 80psi is still sufficient for your weights. Personally, I wouldn't run less than 80 since that is the lowest pressure that either manufacturer lists for that tire. If you want an extra margin of safety, run 85psi.

[4x4van]

timmac wrote:

I don't know why people say you need to weight 4 corners, just load RV even on all sides and just weight the front and back axels, that is all that is needed..

I call BS on weighting 4 corners, not needed unless your motorhome is leaning for some reason..

100% untrue. Very few if any RV's are evenly weighted side to side. While the difference may not be enough to dictate different tire pressures, oftentimes it is. My RV is nearly 1000# heavier on the driver side, due to bedroom slide and kitchen slide both being on the driver side, resulting in a 53.5/46.5 weight bias. The weight bias is built into the coach, yet it does not lean. Assuming anything about an RV's weight results in over or under pressure in your tires.

[rgatijnet1]

Without weighing all four corners, you have to ASSUME that the motor home is balanced equally when loaded. In fact it may be heavier on one side than the other side and the factory just added a heavier spring on that side to compensate and not cause a lean.
I would also weigh the coach with full fuel and maybe 1/2 tank of water.

[blazenpm]

Check your motorhome specs. I just learned not to go by what is printed on the tire, but what the motorhome manufacture recommends for your GVWR and the max wt. per front tires and rear tires. I was going to put 100 lbs. in mine then I looked on the manuf. recommendations and it was 75 lbs. for the front and 65 lbs. for the rear ( I have duel tires in the rear). This will potentially prolong the wear on your tires.

[drwwicks]

Ivylog wrote:
EDIT. When weighing you don't need to weigh both sides and the whole coach. Just weigh one side and the whole coach and do the math. Subtraction works wonders...that only works if the ground besides the scale is the same elevation. Just a little leaning will shift hundreds of pounds. Turn around and reweigh and at the same distance side to side.

Good point. The Flying J near me has level ground to the sides. Only can pull to the right because barriers are on the left.

[Ivylog]

EDIT. When weighing you don't need to weigh both sides and the whole coach. Just weigh one side and the whole coach and do the math. Subtraction works wonders...that only works if the ground besides the scale is the same elevation. Just a little leaning will shift hundreds of pounds. Turn around and reweigh and at the same distance side to side.

[drwwicks]

timmac wrote:
80 psi would be the safe bet and still have a soft ride, you can do the fronts at 75 psi but would not go below 80 in the back, if you tow a trailer with some hitch weight than 85 psi or more in back would be better.

I don't know why people say you need to weight 4 corners, just load RV even on all sides and just weight the front and back axels, that is all that is needed..

I call BS on weighting 4 corners, not needed unless your motorhome is leaning for some reason..

If you don't know what the weights are you can't load correctly. Guessing is an amateurs way. Mine is about 800 heavier on the right side empty so if I want to balance the load I need to concentrate heavier things on the left. I'm not going to be able to get it perfect but now I know which side needs weight. Air suspension will adjust lateral ride if it's set correctly.

EDIT. When weighing you don't need to weigh both sides and the whole coach. Just weigh one side and the whole coach and do the math. Subtraction works wonders.

[mike_brez]

Can't you weigh it like This to get four corner.

[tropical36]

kmb1966 wrote:
Could someone double check me on my air pressure? I could not find a weigh station to weigh all 4 corners, but I do have front and rear weights so far. Loaded the RV for travel.
Front: 6,540 lbs
Rear: 12,200 lbs
Total: 18,740 lbs

Tires are 245/70 19.5 14 Ply.
Hercules tire says maximum pressure 110 lbs. But they only show inflation table for 110 psi. Shows same carrying weights on the Single and Dual as the Goodyear G670 table.

I am putting 95 lbs on all 6 tires.

Don't worry about weighing all four corners, use any inflation chart for the same load range tire and then add 10 - 15psi to take care of all the variables you will encounter, from shifting weight to changes in ambient temp. and everything else, in between.

[jadatis]

Filled in your weights in my made extra save pressure-calculator.
Gave for the maximum speed of tires , wich is most likely 75m/h, next advice.
Front 86 psi Rear 85 psi.
but also derated the tires for as if 99m/h was maximum speed, together with the 10% reserve adding for R/L inbalance, it gave next advice. Front 97 psi and Rear 95 psi.

This is the pressure I advice for maximum reserve with still acceptable comfort and gripp.

Did you have everything in the Motorhome when weighed, so also all the persons. Otherwise we would have to add some weight to the axles and calculate a new advice.

[timmac]

80 psi would be the safe bet and still have a soft ride, you can do the fronts at 75 psi but would not go below 80 in the back, if you tow a trailer with some hitch weight than 85 psi or more in back would be better.

I don't know why people say you need to weight 4 corners, just load RV even on all sides and just weight the front and back axels, that is all that is needed..

I call BS on weighting 4 corners, not needed unless your motorhome is leaning for some reason..

[RE_Todd]

I just weighed my Super C today to do this. I used the Uniroyal chart for Load range G, all of mine are G's. 6200 steer, 75-80 PSI. 12600 drive, 85-90 on the duals.