Question 4 corner weights

[sheridany]

I did a four corner weight today and my steer wheels have what I think is a significant difference.

disclosures
Fuel 1/2 tank
Water tank empty
Gray and black empty
I used 3 truck wheel weight scales that I own so each side was measured individually. I did not lift the other side. The ground was fairly level.

Otherwise the coach is loaded for trips. Bear in mind our trips are not like you pros out there.

The front difference is concerning.

I have the newmar weights at home and I’ll compare those.

@Neal in another post you had mentioned a similar issue when you did FPU? Is there a resolution? Before I start ripping everything apart I want to get some advice from you all

here are factory weights from Newmar.

 

[Neal]

When at FPU and getting corner weights they told me that left/right should be within 1000 lbs of each other. I think they adjust ride height on the airbags to balance the weight. Imagine "tipping" your coach left/right to get it balanced.

 

[sheridany]

Thank you. Sounds like I need to go to FL.

 

[sheridany]

So I went to FL and they said if the ride height needs to be adjusted it would be obvious and tilting

They checked the measurements and said it was fine or within specs. The FL shop suggested I call FL support and a very unfriendly person refused to log a case said “not our problem“. I am going to call Newmar in the morning to see what they say. Any other suggestions on how to rectify this problem are appreciated.

 

[Neal]

I thought about my corner weights this morning, I bet with my new Dometic cooler in the front right basement and my Pellet Grill in the right of the slideout tray I'm probably heavier right than left. I head to Gaffney in April and I think they can do corner weights but will I do anything about it? Probably not. Reason is I have HWH Active Air and I have no idea how to make changes to it should airbags need adjustment.

Moral is, is this really something you need to worry about? I'm not sure a 1500 lb difference is really something to worry about but I may be wrong, this is not my expertise. Those with much more RV experience than me please chime in on left/right weight differences and what the tolerances are, if any.

 

[Joe Hogan]

Being a tech nerd I think about this stuff. The tires on my rig are close enough to max weight that if the CanyonStar is too far out of balance I may exceed the working weight of the tires as well as having the inflation pressure too low for weight carried by the wheel position. I run at the max axle weight on the drive axle most trips and consequently max cold tire pressure. If the side to side balance is too far out of wack I'll be exceeding limits on tire position weight. This may not be a concern for the DP folks.

 

[sheridany]

I have sent all the data to Newmar and await a formal response which I will share on this thread. We are headed to Indio on Saturday and we may do yet another weigh session down there with a business that does RV weighing.

 

[sheridany]

Newmar replied and said they think the scales are off even though i did it two different ways for that big a difference which is possible but I doubt it. Whatever, I am not going to stress about it. I will find another scale and do it again.

 

[sheridany]

i had the coach weighed by an RV shop that does 4 corner weighing and they got the similar results as I got where the front axle has a difference over 1000 pounds side to side. I am really concerned about this as everything i have read said no more than 500 lbs max side to side. I honestly do not know what to do next but I sent an email to Newmar again showing the comparable results I have gotten 3 times. Nevertheless, I need to get this fixed and I hope Newmar can suggest some solutions since this is a potential safety and liability issue.

	3/14/2020​
		Right front		Right drive	Right tag
		5440​		8170​		3880​
		6510​		7940​		4140​
		Left front		Left drive		Left tag
		1070​		-230​		260​
Newmar Factory		Right front		right drive	right tag
		5580​		7325​		3750​
		5860​		7845​		3865​
		Left front		left drive		left tag
		280​		520​		115​
Difference Vs. Factory		Right
		-140​		845​		130​
		650​		95​		275​
		Left

 

[BGMAC]

Between 2017 and now we’re there any additional items added to the coach Or things that were done to customize it?

 

[sheridany]

None at all. Standard coach.

 

[stang37]

Sheridany

I have a 2016 Ventana 4002 and my factory weights are really close to yours. I myself do not like the Left steer side so much heavier than the Right but I have found there isn't much you can do since the major weight for the Left side is the batteries. I have since moved a 150 lbs. to the right front, hoping to get the front closer and remove some lbs. from the right rear. I haven't weighed to see the difference . Here are my factor weights. Total actual weight 34,620. Left steer 5,775, Right steer 5,780, weight difference +5 right steer, Left drive 7.660, Right drive 7,260, Weight difference +400 left drive, Left tag 4,100, Right tag 4,045, Weight difference +55 left tag. Front axle 33%, Drive 43%, Tag 24%. Left side 51% Right side 49% While at the HOOTS rally in 2018 I had all 4 corner weighted. My total actual weight 36,980 Left steer 6780, Right steer 5,490 weight differences +1,290 left steer , Left drive 7,550, Right drive 8,380, weight difference +830 right drive, Left tag 4,320, Right tag 4,370, weight difference +50 right tag. Front axle 33%, Drive 43%, Tag 24%. Left side 50.4% and Right side 49.6 I'm not sure how my left steer grew +995 lbs. and my Right steer lost -290 lbs. from the factory numbers other than me sitting in the drivers seat and the wife in the copilot seat. Neither of us weight that much!! The side to side and front to back % all match from Newmar to my HOOTS weighting. I did have a full fuel tank and fresh water tank and other tanks empty. Ride height, tire pressures and everything I can think of were good to go. Saying all this my tire wear and temps have been great, coach doesn't pull either direction. It might just be the way it is. If you figure or find something to change please pass it along.

 

[sheridany]

@stang37 Thank you for sharing that with me. I will try to get to the bottom of it and if I do, I will definitely post here.

 

[MapNerd]

I have the newmar weights at home and I’ll compare those.

What are these “Newmar weights” you speak of and why have I not heard of these?
NVM. I got it. I was thinking there were some Newmar scales I could buy, haha.

Also, while this will actually make the situation worse I’d suggest weighing with a full tank and if you travel with fresh water, I would offer that its best to have that filled to the level that you depart with. The goal being to know your worst case scenario on weights and set your tire pressure accordingly. As you move down the road, you’ll burn fuel and lose some weight. Plan for the worst and hope for the best is my motto.

As for your left-right difference on the front axle, I’d say it warrants some shuffling of items.The question of any mods or upgrades you may have performed since your last weight is also a good point. Could be a change in batteries, maybe you added a shelf above the freezer (assuming you have one) and put some tools or something else heavy there. Neal’s point of the dometic cooler up front on the right is exactly what I was thinking. I know it causes a small DS-ODS difference for us.

 

[sheridany]

As for your left-right difference on the front axle, I’d say it warrants some shuffling of items.The question of any mods or upgrades you may have performed since your last weight is also a good point.

I honestly wish I had stuff to shuffle but we don't live in our coach and use it primarily to go to skeet shooting tournaments, and secondarily take some trips. The biggest thing I have in the slide tray is the hammock and some supplies in bins like drying towels, filters, extra parts etc. I moved the tool box and heaviest items to the passenger rear compartment in an attempt to shift some weight around. Even in the compartments inside don't have a lot. To put it in perspective, I was reading @stang37 post #12 again, and I added in the calculations he had and we are not far off from the factory weight distribution and if you compare to the GAWR, we are significantly under the maximum by almost 8,000 lbs. We weighed with a full tank of gas and water.
Maybe I am just worrying too much, but I can't help but remember on the other forum someone saying no more 500 lbs side to side.

	3/14/2020​
		Right front		Right drive		Right tag		Totals
		5,440		8,170		3,880		17,490	48%​
		6,510		7,940		4,140		18,590	52%​	36,080
		Left front		Left drive		Left tag
	Total	11950​		16110​		8020​			VS GWVR	(7,920)
	Side to Side Difference	1,070		-230​		260​
			vs. Factory		vs. Factory		vs. Factory
Passenger Weight Distribution		31%​	-2%​	47%​	3%​	22%​	-0.3%​
Driver Weight Distribution		35%​	2%​	43%​	-2%​	22%​	0%​
								GWVR	GCVR
	GAWR	14,000		20,000		10,000		44,000	59,000
	WEIGHT DIFFERENCE vs GAWR	(2,050)		(3,890)		(1,980)

 

[stang37]

I'm not a full timer either and I guess I don't carry enough heavy stuff to shift. I move 150# from the compartment just in front of our TV to the compartment under the copilot seat. Understand that's not a large compartment. 26D x 48L x 18H. I also move the Blackstone grill, propane cylinder, metal lawn chairs, 8' aluminum ladder, extension poles and a lot of misc stuff to the center compartment where the sliding tray is located in an effort to center as much weight as possible in the basement. I have my tool box, tire covers, air hose and sewage stuff in the compartment behind the tag on the drivers side. If we get to HOOTS this year I will 4 corner weight again with stuff relocated just to see the difference. Running out of options based on what we carry when traveling. Thanks for any suggestions.

 

[sheridany]

Here is the response I got from Newmar.

Erica asked me to read through your email and offer any suggestions I might have concerning the weight difference in your front axle. I hope to ease your fears as there is a lot of misinformation on the internet that can drive a person crazy. For starters, Newmar has probably the best balanced RV’s on the market. The numbers you gave are not that concerning to me as, the rule of thumb for front axle difference is 1,500 lbs. between the two, and you’re well within that tolerance. With the numbers you’ve given, there should be no concern for flipping a coach due to a blowout. You would certainly want to up the tire pressure on the side that is heavier but other than that, I wouldn’t be that concerned. I have seen brand new coaches from other manufactures with up to 5,000lbs. heavier on one complete side. If you’re still concerned, I would suggest taking the coach to different Freightliner shop to have them look into the issue.

 

[sheridany]

This is my last post on this topic unless something comes up that is earth shattering relevant, I promise.

In the quest to get more intelligence, I reached out to Tireman9 on the other forum who is a well known author on tire safety and retired engineer from a major tire manufacturer. Here is his reply.

You may have miss-understood the side to side weight comments.


It is suggested that people get "4 corner" weights rather than just axle weights, as it is known that some coaches are unbalanced side to side.
We do this because if you only get axle weights and simply divide by 2 and assume your side to side weights are even, you could end up with an overloaded or underinflated tire IF the sides are not close to even.
Not sure where the 500# figure comes from other than looking at the load increments in the tables for each 5 psi. You will see that with some large tires the load capacity can increase by a few hundred pounds with an increase of 5 psi.


I do not remember ever seeing a "should" not be more than 500# different statement



You have confirmed that your coach is not balanced side to side and it appears you have made a good effort to get more balanced but have not been able to because of the design / layout of your coach.


With that in mind, and knowing the load on the "heavy end", you need to consult the Load/Inflation tables and use the heavy end weight to learn your MINIMUM inflation for all the tires on that axle. I still recommend you add 10% to the table inflation number as long as you do not exceed the max inflation rating for the wheels. This 10% helps avoid TPM low-pressure warnings due to an occasional drop in Ambient air temperature


I trust you have confirmed with your RV Mfg that the wheels are capable of supporting the heavy end load.
I hope this clarifies what you need to do and answers the "Why" we suggest you get the weights on each end of each axle.