Class C Weight Questions and Ride-Rite Question

[BFL13]

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!

[PghBob]

Hi BFL13. Since you noted that you are new to Class C, I just wanted to remind you of a couple things. If you already know these things, please ignore this post and pardon my response. Understand that when you are weighing for GVWR, your RV needs to be fitted out just as you intend to use it. You must allow for the weight of all passengers, full propane tank, full fresh water tank, clothes, food, pets, and stuff. From your initial post, I could not tell whether you took these items under consideration when you weighed. Also, if you exceed GVWR, you are placing a stress on not only the tires, but the suspension and drive train. Finally, it usually isn't a point of whether you get "caught", but rather if something fails causing an accident you may be expossed to potential legal issues. Best wishes for figuring out your rig.

[Airstreamer67]

About the air bag pressure, I added an air gauge in the cabin and plumbed it into the air bag system. Since my Firestone Ride Rites are plumbed together, it only took one gauge.

For about 50 bucks, it sure is a comfort seeing what the air pressure is at all times, and now it's a lot easier determining what pressure feels best for any given load.

Another thing I did was to add a platform for a large tool box on the front hitch. That box is low enough to not cause vision, air-flow or engine-heating problems, and it allowed me to put about 150 pounds of heavy tools on the front end, where a little weight is beneficial to compensate for the weight imbalance caused by behind-the-axle overhang.

[BFL13]

I can try some more air in the front. The thing now is to go camping and get some driving time with it as is, now I have back tires at 65 and the Ride Rites at 30 and see how that goes.

I have never driven a Class C or a Dually truck before, so no idea what is normal and what is not for handling. With that 11 ft of overhang behind the back axle, you just know the truck part is not going to be all that happy, so I'll take it easy.

Thanks for all the help everyone.

[ron_dittmer]

When it comes to tire pressure, heed my warning about tires gauges HERE.

[FunTwoDrv]

BFL13, The heavier rims look interesting... But before spending money, I'd run those tires a little higher than 58lbs. A little more air pressure may address the steering issue you noted.

Gary

[CharlesinGA]

While it will be expensive, if your MH is nice and you intend on keeping it, it may be worth looking into replacing the rims. CoachDad in THIS THREAD gave a link to an outfit that makes replacement rims in 17.5 inch that allow for much stouter truck tires of about the same diameter as the original 16 inch rim tires on your C class.

https://ricksontruckwheels.com/wheels-ford-e350450.php

This looks like a viable option and will give you real truck tires with much higher weight ratings.

Charles

[BFL13]

OK I won't move the spare to up front right away. If it's been there since 1991 things can't be all that bad. That means I can still have a set of longhorns up there like those guys in Texas all have! 🙂

On the steering, I wonder if the back being so heavy is lifting the front a bit, although it all seems level. I notice that with no hands on the wheel it drives straight like it should, but there is more play in the steering wheel than I am used to for turns.

It all works, but I would rather have a more direct feel to it, a tighter wheel, whatever I am trying to say--at least I know what I mean! 😞 Could that be from not enough weight up front? I don't know Ford trucks though. Maybe it is normal. The garage guys didn't say anything about it, and they did a thorough inspection.

[FunTwoDrv]

BFL13, Interesting discussion... I'll throw my numbers in as well. We're about 4400F and 7700R. We're running 65psi front and 70psi in the rear. We've run the air bags anywhere from 30psi to 70psi. At the higher bag pressures, the unit seems to be a tad more stable at the expense of ride quality.
My thinking is "Total Weight" isn't very critical when it comes to setting tire pressures. (That seems to be dictated by axle weights.) Although, it is important if you get stopped by a LEO and are deemed overweight!

Gary

[pianotuna]

Hi BFL13,

Not necessarily a good idea. When I had an expanded metal rack made for the generator initially it was on the front. There were three effects.

It helped with the steering,

It caused the engine to run 30 f hotter.

It interrupted the laminar air flow and cost me 20% on fuel economy. (i.e. 10 mph down to 8).

The rack is now on the back.

BFL13 wrote:
I figured out there is one thing I can do after all, but I don't know if it would be worth the bother. Move the spare tire from the back bumper to the front.

Using the leverage weight calculator for a snow plow from my Chev truck manual, and assuming the spare weighs 75 lbs (it is very heavy--I had to take one off to get a leak fixed--was the valve core--had a struggle lifting it up into the truck's box ) I get:

75 x (140 + 176)/176 = 135 lbs on the rear axle from that 75 lb spare.
140" is the distance of the spare back from the axle and 176" is the wheel base.

I am over RGAWR by 182 lbs according to the scales. What I don't know is the exact weight of that spare and whether this amount over RGAWR is trivial or is serious enough to warrant moving the spare to the front.

[j-d]

About that D vs. E thing. In our type of tire, I think what's happening is they're being made mostly in E.

[BFL13]

I figured out there is one thing I can do after all, but I don't know if it would be worth the bother. Move the spare tire from the back bumper to the front.

Using the leverage weight calculator for a snow plow from my Chev truck manual, and assuming the spare weighs 75 lbs (it is very heavy--I had to take one off to get a leak fixed--was the valve core--had a struggle lifting it up into the truck's box ) I get:

75 x (140 + 176)/176 = 135 lbs on the rear axle from that 75 lb spare.
140" is the distance of the spare back from the axle and 176" is the wheel base.

I am over RGAWR by 182 lbs according to the scales. What I don't know is the exact weight of that spare and whether this amount over RGAWR is trivial or is serious enough to warrant moving the spare to the front.

[BFL13]

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. 🙂

[ksg5000]

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]

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--.