Tire Pressure 6 Corner Concerns

[CA_Traveler]

Here’s the weight on one of the free Oregon scales which appeared to be mostly level off to the side. Note that I measured the total and right side and the left side is the difference.

Front right 7,000 left 7,550, total 14,550
Dual (both tires) right 10,750 left 9,250, total 20,000
Tag right 2,000 left 2,850, total 4,350

I’d certainly like the side to side weights to be closer. The tag doesn’t have enough weight which is consistent with its much less wear than the duals at 31K miles.

Continental HSR2 295/80R 22.5 on the front which is a much better riding tire than the replaced Badyears. Planning to replace the rear Badyears in a month.

Continental Load Inflation Table maximums: Single 7,830, dual 6,945. I’m planning to add 2,000 lbs to the adjustable tag weight which will reduce the dual weight. I estimate this will add about 325 lbs to the front. The tag suspension is currently set to 30 psi and can be increased.

Anyone have an idea how tag suspension psi relates to tag weight or other suggestions?

[CA_Traveler]

All good input and appreciated. I will get everything checked and resolved.

I had to replace the front Badyear tires due to river edge wear which is a know tire defect. The remaining tires are 2007 originals with 31K miles and 3 of them have river edge wear. So they need replacing for both age and the defect.

I plan to move the 2013 front tires with 7K miles to the tag. The tire shop said they would have to be remounted because it's a 180 degree rim rotation and there would be permanent unacceptable marks on the alloy rims due to contact with the steel hubs.

[Daveinet]

Hey something is really screwy. Your tag left vs right is opposite of the drive axle left and right. I'll bet your coach weight left to right is dead on. AS Bret said, you have a valving problem, not a weight distribution problem. Your 2 axles are fighting each other.

[Ivylog]

I would run the two tires on the tag longer as they have not been doing much. In say 4-5 years I'd buy two new and put them on the front (I like new tires on the front) and put the two off the front on the tag at that point.
I've been concerned about being over 20K on a single axle, BUT recently a fellow member provided this link where we are special and we can have 24K on a single axle.

[CA_Traveler]

I thought by 09 Monaco had moved the fuel tank further back to shift some weight off the front.
With those weights are you running 110/85/75 in your tires front to back

Maybe, my chassis was started in 08. I'm running 115/90/90 and will adjust when I get new tires.

[CA_Traveler]

I measured the total and right sides. Measuring both sides was not possible at the last station. Next Fri I'll be at the station 2 miles east of Tillamook and perhaps I can measure both sides there.

[Bikeboy57]

It was not clear to me if you arrived at the total axle weight by adding the two sides or actually weighing the axle. From your math it appears you added the two sides.

Just for the sake of argument, lets say the slope of the ground and the scales shifted weight to the side being weighed. If you just add the right and left, then you will arrive at a total weight that is higher than actual. On the other hand if the slope unloaded the side on the scale, the actual axle weight could be even higher than what you calculated.

I would think it would be a good sanity check to put both tires of an axle on the scale and use that measurement to verify the side to side.

[CA_Traveler]

Good point about the dual side to side weight being the opposite of the front and tag. OK I'll see what I can do about finding a level area and checking the ride height. I'm traveling and don't have the equipment which is at home of course but I may be able to borrow some equipment in Portland.

Your points about not changing the tag are good and I didn't initially realize how close the front was to the GAWR. So both the front and dual are maxed out.

If ride height changes are needed I'll have it done as I won't get under the air suspension chassis.

For service I'll probably go to Country Coach in Junction City, OR as they have a full alignment etc shop.

[wolfe10]

Agree, I would NOT add to tag-- you are too close on the front axle to do that.

All wheel position weighing will be done again next week at the FMCA Convention in Redmond, Oregon.

[Ivylog]

Where to start? I have much the same coach, just older.
I think you can get your side to side weights better by adjusting the ride heights on the dive axle as the other two axle are 180 out. On perfectly level ground is the coach perfectly level or measuring from the ground up to the exact same point on both side is it the exact same distance? Are the steel plates on the drive axle air bags the exact same distance on all four airbags... 9.5" I think? Not sure of your floor plan but I'm very close to balanced side to side.
While your front tires are capable of more weight I'm not sure your front axle is and I agree that 2000 lbs more on the tag (a 10 psi increase) will put 325 on the front, but why?
I thought by 09 Monaco had moved the fuel tank further back to shift some weight off the front.
With those weights are you running 110/85/75 in your tires front to back
Being off center on the scale is not going to change the reading but if the coach is leaning a fair amount it will. The next time you weigh put the other side off the scale and see what you get. The OR scales I've used are very close to the same elevation as the pavement besides it.

[Bill_Satellite]

Assuming your front gross axle weight is correct (or even close) I would not adjust the tag pressure. You are very close to the max now and any adjustment could take you over the limit. You might want to see if there is some weight you can move from one side of the coach to the other (have your wife move here shoe collection to the other side!) but I would not screw with front to rear weights.

[Peralko]

Have you thought about going to a rally, like an FMCA rally? They usually have folks there who can do a 6-point weighing of your coach, which should be more accurate than using a truck scale.

[CA_Traveler]

Also the tag/dual separation is 41" which means the dual and tag weights are on the edge of the scale. I can't help but wonder how accurate the truck scales are near the edge.

I had no way to measure the ground vs scale level so I should probably just use the total axle weight until I can get accurate side to side weights. I'm also aware that there are some inconsistencies in the numbers I posted.

In several weeks I'll be at another ODOT scale and plan on more measurements including tag adjustments.

[CA_Traveler]

I'm calling ODOT to have them level the next scale I use. 🙂

But I have a starting point to get more accurate weights and make any tag adjustments. I appreciate the input.

I'll call Monaco to get the ride height measurements and see if they have a factory tag psi setting.

[CA_Traveler]

Yikes, Front GAWR is 14,600. Guess DW will have to ride in the rear. :B
Dual 20,000 and tag 10,000.

It will be awhile before I can get and check the ride height adjustment. I can say that when on level ground the rig is very close to level. ie Very minor or no leveling of the rig. I've verified that the refer is level when the leveling system indicated the rig is level.