Forum Discussion

BFL13's avatar
BFL13
Explorer II
Oct 22, 2017

Class C Weight Questions and Ride-Rite Question

I am new to Class Cs and to Dually trucks, so have some basic questions from weighing it today.

Problem to start with is the scales were small, so one axle at a time only.

Question--is the total of the front and rear weights the same as the actual total weight? ( I am thinking there is a little weight from the other end adding in, so you get a higher than real total by adding the two--but that could be all wrong--so I am asking.)

In this case, Front 1630/3586 and Rear 3570/7854 so the total of those is 5,200/11,440 GVWR is 4,989/11,000

So I wonder if I am really over GVWR or not.

I also did one side at a time and the right front was more than the left front, while the right rear was less than the left rear but not by a lot.

It appears I am over RGAWR though.

RGAWR 3479/7672 and Scales 3570/7854

(RR was 1760 and LR was 1860 for total 3620 which is over the two sides measured together---which is why I am wondering about the total weight as in the question above on GVWR.)

The door specs say LT215/85R16D to 58 PSI but the rig has 16Es on it. I have them at 58 PSI. I could easily go higher on the rear dually Es. Do I need to? They are rated 1120 single and two makes 2240. left side was 1860 and right side was 1760 on the scales. So the tires could do it ok with that 2200 limit --I have not checked the tire tables for psi and the scale wts on the Es, so far.

The MH also has Ride- Rites for whatever reason some previous owner had. Perhaps he saw the above numbers in his day too?

There was no air in the bellows when I got this, and the instructions say minimum 20 lbs. It was level with no air in them. You are supposed to air them up till level. It was already level. So I have no clue-- I put 30 lbs in them and I can't tell if any different. Each bellows is the same height and within their height specs.

My question is whether I need these things. Maybe just up the PSI in the rear tires instead? The Ride-Rites seem like they would be a PITA--you have to check their air every week it says, and the air valves are hard to see and get at, up in the sani-dump compartment. I'd just as soon not have them unless I must. Any thoughts on that are welcome!

So this newbie Class C owner needs some advice on all this---thanks!
Class C
  • ScottG's avatar
    ScottG
    Nomad
    Oct 22, 2017
    Yes, the total of front and rear is the total weight.
    I would run more air and see if it drives better. The door sticker was probably placed there before the house was added.
  • BFL13's avatar
    BFL13
    Explorer II
    Oct 22, 2017
    Yes it is an "incomplete truck" and could have been an ambulance or whatever, but was made into a MH in this case. (in Vernon, BC )

    Ok so I am just over GVWR but there is nothing I can do about it--it is what it is since 1991. :) Not much I can do about the Rear axle wt either. ( I guess towing a car is out though- :) )

    The ride as is, is quite stiff. I don't know what is normal with these things. Steers well, etc. Garage inspection says it is all good.
  • Snowman9000's avatar
    Snowman9000
    Explorer
    Oct 22, 2017
    When used as duallies, the tires are de-rated by something like 10%. I don't recall why. Google RV tire chart and find your tires there, you'll see the ratings at various PSI.

    I would not be surprised if the shocks were not good.
  • BFL13's avatar
    BFL13
    Explorer II
    Oct 23, 2017
    Ok, so my Hankooks have the same markings as the Michelin same size so I used the M table as I couldn't figure out any H tables shown.

    Sidewall on my Hs says 1120 kg dual at 80lbs and the M table says 4480 needs 80 lbs. Table says you need 60 lbs for 3600 kg.

    So mine are at 58lbs per door specs and the scale weight was 3570 so I am fairly close on that already. Since I am over weight a bit, I think I should put 65 lbs in the 4 back tires instead of 58, and have some margin there as well for the fact that one side takes more than the other, and leave the fronts alone.

    The door specs say 58 for the fronts too, but the front weight is only 1630kg, so that makes no sense to me, but the door says what it says. (On my Chev truck the door specs say 55 front and up to 80 rear. I never had a Ford truck before, so I will just obey Ford orders and leave the fronts at 58 :)

    (Actually, the garage mechanical inspection had no issues with the shocks. It all came out pretty good. Thanks, previous owner(s) !! )
  • DrewE's avatar
    DrewE
    Explorer II
    Oct 23, 2017
    The total weight would be the sum of the individual weights only if you keep the wheels on a level while weighing. If one is higher than the others, the numbers will be off. (More accurately, if the relative levels of the wheels changes between weighings, they will be off.)

    There are two reasons for this, both boiling down to weight shifting. The first is that any leaning of the motorhome will shift the center of gravity towards and away from different wheels. The second is that the springs in the suspension when compressed have more force exerted (and hence less on other wheels). As these two tend to work in opposite directions, at least much of the time, it's hard to say exactly how the weighings will be affected.

    I am quite satisfied with the ride-rites on my motorhome. They probably won't require checking quite as often as you're suggesting (but it would be wise to be on top of that until you know for sure how much they tend to leak down), and they help stiffen and stabilize the rear suspension besides keeping the ride height at a good level. Since you can't measure the unloaded ride height to know where to adjust them, it's somewhat of a guessing game. You'll probably be best off with more than 20 pounds; I find 40 is about right for my motorhome.

    It may well be that the front is riding a little lower than it really ought to since it's fairly heavily loaded too and it's possible the springs have fatigued over the years. Assuming you have the twin I beam suspension, it is a good idea to get the ride height about right in the front because the wheel camber is partly a function of ride height and if it wallows too much it can cause the inside of the front tires to wear excessively.
  • BFL13's avatar
    BFL13
    Explorer II
    Oct 23, 2017
    Well this is getting complicated! :) I do suspect the totals don't match--look at the side by sides EG. You get some of the other side's weight with just one side on the scale in the case where I was doing it. Not sure if the roadside was higher or lower than the scale platform, so can't help with that now. I just figure nothing was too drastic to worry about with the numbers I got.

    I would like to get this MH on one of those really big scales that can weigh it all, to then know the truth about my weight wrt GVWR.

    There is no likelihood I will be pulled over and checked, so I will not sweat the rules as such. I am so close at maybe 440 lbs over 11,000 I feel safe enough using my own brain if that is any use :)

    Interesting about the Ride-Rites. I have the manual for them and some bulletins from 1986 (so maybe these are original equipment in 1991?), so that is where I got the idea they need checking so often. I will give it all some time and miles and see how it goes. I figure they are there for a reason, so I better not do anything rash just yet.

    Anybody see anything peculiar in my results at the scales? Are all Class Cs like this? I did see the other thread running now on a shorter one, where a comment was made that they are usually heavy at the back.
  • pauldub's avatar
    pauldub
    Explorer
    Oct 23, 2017
    "In this case, Front 1630/3586 and Rear 3570/7854 so the total of those is 5,200/11,440 GVWR is 4,989/11,000"

    This is totally confusing me. Are you saying the weight on one front tire is 1630 and the other one is 3586?
  • BFL13's avatar
    BFL13
    Explorer II
    Oct 23, 2017
    pauldub wrote:
    "In this case, Front 1630/3586 and Rear 3570/7854 so the total of those is 5,200/11,440 GVWR is 4,989/11,000"

    This is totally confusing me. Are you saying the weight on one front tire is 1630 and the other one is 3586?


    Sorry, the scales here show in Kgs to nearest 5 so I did lbs too (using 2.2 times) The Ford door specs aren't quite 2.2 but whatever--.
  • ksg5000's avatar
    ksg5000
    Explorer
    Oct 23, 2017
    I weighed my 92 Class C and adjusted the tire pressure based on the Michelin tables - made a nice difference in ride comfort. I use E tires but the rims are rated for D's. I don't have air bags so can't help with that - maybe they were added because prior owner thought it was necessary when towing?
  • BFL13's avatar
    BFL13
    Explorer II
    Oct 23, 2017
    Good point about the rim specs. I don't have that info for my wheels, but supposed to take Ds. I saw a note somewhere in all the bumph for the rig that said 6" and don't use tires that need 6.5"? Ds are good to 65 lbs so I figure 65 in the Es will be ok even if the rims will only take Ds. Can't see any reason to go over 65 since that will carry more than the GAWR anyway. Perhaps a previous owner put the Es on instead of Ds was just to keep from driving all the time at max PSI on the back tires. The spare is a D, probably from before.

    I did learn a lot from getting it on the scales and asking about it here, that's for sure. I would never have known it was over its RGAWR and at or just over its GVWR. It has a towing hitch receiver, but I don't see how you could put any weight on it since the rig is already over its RGAWR.

    Good reminder about the rim psi limit if ever intending to go even more above the RGAWR when towing, to exploit having Es instead of Ds. ( I don't intend to!) I wonder what those previous owners got up to in their day! Maybe that explains why it has Ride Rites. :)

About Motorhome Group

38,705 PostsLatest Activity: Jan 14, 2025