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Old 05-25-2021, 08:53 PM   #1
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over weight

We just weighted our Class C rv, and found the real axel came in at 10200 lbs, but is rated at 9600 lbs, the front axel is 700 lbs under its rating. My question is this too much over the rating? And I do know we could try to move stuff to the front of the RV, but, most of our storage is in the rear of the unit both inside and outside. So moving stuff is not a real option. We do carry just bout 8 to 10 gals of water in the fresh water tank, so that's not going to make a big dent in the 600 lbs. Is being 600 lbs over unsafe??? thanks

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Old 05-25-2021, 08:57 PM   #2
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Originally Posted by tugboat911 View Post
We just weighted our Class C rv, and found the real axel came in at 10200 lbs, but is rated at 9600 lbs, the front axel is 700 lbs under its rating. My question is this too much over the rating? And I do know we could try to move stuff to the front of the RV, but, most of our storage is in the rear of the unit both inside and outside. So moving stuff is not a real option. We do carry just bout 8 to 10 gals of water in the fresh water tank, so that's not going to make a big dent in the 600 lbs. Is being 600 lbs over unsafe??? thanks
Depends on which lawyer you ask.
If you're over on the axle you may also be over on the tires.

Most Class C MHs leave the factory at or just below the RAWR.
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Old 05-25-2021, 08:58 PM   #3
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Originally Posted by tugboat911 View Post
We just weighted our Class C rv, and found the real axel came in at 10200 lbs, but is rated at 9600 lbs, the front axel is 700 lbs under its rating. My question is this too much over the rating? And I do know we could try to move stuff to the front of the RV, but, most of our storage is in the rear of the unit both inside and outside. So moving stuff is not a real option. We do carry just bout 8 to 10 gals of water in the fresh water tank, so that's not going to make a big dent in the 600 lbs. Is being 600 lbs over unsafe??? thanks
Ford sets axle weight limits for a reason.
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Old 05-25-2021, 09:46 PM   #4
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Lots of people simply don’t worry about it, but if it was mine I’d fix it. 600lbs is not insignificant.
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Old 05-25-2021, 10:01 PM   #5
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If you dig deep enough into Ford's axle ratings: you will learn something that is very interesting...
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Old 05-25-2021, 11:44 PM   #6
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If you dig deep enough into Ford's axle ratings: you will learn something that is very interesting...


That’s cryptic!
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Old 05-25-2021, 11:53 PM   #7
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Old 05-26-2021, 11:20 AM   #8
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Bob is right on the money... the actual axle ratings are higher than you think. Most of the time the numbers are just paper changes from one chassis variation to the next and the axle components can be the same across different vehicle GVWR's.

My Magnitude SV34 has a GVWR of 19,500 and I am not worried if I am a few hundred pounds over. The rear axle on the F550 is rated for 14,706lbs (the front is rated for over 7000lbs).

From a braking perspective the brakes can handle extra load as well; especially since I have engine braking.

The weakest links in weight ratings are the tires first and then the suspension (springs). You might be able to go over the weight rating from an axle perspective without much worry but I would not go over (or near) the tire weight ratings.


Here is a comparison of the Ford Super Duty models and their rear axle ratings as an example of the axle contruction and weight ratings across the various chassis variations:


F350 DRW Pickup: M300 axle, 9650lb rating, 4.5" tube, 1.47" minor diameter, 37 spline shafts

F350 DRW CC: M300 axle, 9750lb rating, 4.5" tube, 1.47" minor diameter, 37 spline shafts

F450 DRW Pickup: M300 axle, 9650lb rating, 4.5" tube, 1.64" minor diameter, 41 spline shafts

F450/F550 DRW CC: M300 axle, 13,660 lb rating, 4.5" tube, 1.64" minor diameter, 41 spline shafts

F550 CC w/Payload Plus Package: M300 axle, 14,706lb rating, 4.5" tube, 1.64" minor dia, 41 spline shafts. The CC axles have a SPL-55 end yoke, while the PU versions have a circular flange driveline attachment.

The CC axles have spring perches at 41.56". while the PU versions have spring perches at 45"

All 450/550 have the same brakes. 350 brakes are smaller.

Quick summary:

-F350 PU/F350 CC - the only difference is the paper rating

-F350 DRW and F450/550PU and CC - larger diameter axle shafts, splines, and brakes

-F450PU/F450 CC - the only difference is paper rating

-F550CC/F450 CC - no difference

-F550 CC w/ payload plus - the only difference between it and a 450PU/450CC/550CC is paper rating
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Old 05-26-2021, 11:23 AM   #9
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DING DING DING!!!
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Old 05-26-2021, 11:30 AM   #10
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The OP's bigger concern is his stock tires and not the axle.

Most Class C's stock tires are pushed to the limits. The chassis manufacturers use LT rated tires versus commercial truck rated tires because they don't know if the chassis will be an airport shuttle, ambulance, box truck or a motorhome. And the RV manufactures don't both to upgrade the tires and suspension for the loads they put on the chassis.

Light Truck tires are meant to carry heavy loads at short intervals. Commercial Truck tires are meant to carry heavy loads all the time and at highay speeds.

A motorhome can be classified as a full-time heavy load and in my opinion is not what LT tires should be carrying.

The first upgrade anyone should make on a Class C 25' or longer is getting rid of the LT tires and upgrading to a commercial rated tire..... again.... just my opinion.
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Old 05-26-2021, 11:37 AM   #11
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Having owned numerous HD Fords over the years the Tires were always the weakest link unless they were 14-16 ply

Lighter trucks with 16" we ran all steel

Unless it has changed recently the F550 uses the same front wheel hub assembly as the F250 by means of an adapter

Quote:
Originally Posted by Judge View Post
Bob is right on the money... the actual axle ratings are higher than you think. Most of the time the numbers are just paper changes from one chassis variation to the next and the axle components can be the same across different vehicle GVWR's.

My Magnitude SV34 has a GVWR of 19,500 and I am not worried if I am a few hundred pounds over. The rear axle on the F550 is rated for 14,706lbs (the front is rated for over 7000lbs).

From a braking perspective the brakes can handle extra load as well; especially since I have engine braking.

The weakest links in weight ratings are the tires first and then the suspension (springs). You might be able to go over the weight rating from an axle perspective without much worry but I would not go over (or near) the tire weight ratings.


Here is a comparison of the Ford Super Duty models and their rear axle ratings as an example of the axle contruction and weight ratings across the various chassis variations:


F350 DRW Pickup: M300 axle, 9650lb rating, 4.5" tube, 1.47" minor diameter, 37 spline shafts

F350 DRW CC: M300 axle, 9750lb rating, 4.5" tube, 1.47" minor diameter, 37 spline shafts

F450 DRW Pickup: M300 axle, 9650lb rating, 4.5" tube, 1.64" minor diameter, 41 spline shafts

F450/F550 DRW CC: M300 axle, 13,660 lb rating, 4.5" tube, 1.64" minor diameter, 41 spline shafts

F550 CC w/Payload Plus Package: M300 axle, 14,706lb rating, 4.5" tube, 1.64" minor dia, 41 spline shafts. The CC axles have a SPL-55 end yoke, while the PU versions have a circular flange driveline attachment.

The CC axles have spring perches at 41.56". while the PU versions have spring perches at 45"

All 450/550 have the same brakes. 350 brakes are smaller.

Quick summary:

-F350 PU/F350 CC - the only difference is the paper rating

-F350 DRW and F450/550PU and CC - larger diameter axle shafts, splines, and brakes

-F450PU/F450 CC - the only difference is paper rating

-F550CC/F450 CC - no difference

-F550 CC w/ payload plus - the only difference between it and a 450PU/450CC/550CC is paper rating
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Old 05-26-2021, 06:27 PM   #12
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Sh1t happens — for real. I have personally seen a few trucks with broken axles, and it’s not pretty. Axle itself isn’t the only problem, otherwise there would be guys on the internet advertising installation of Freightliner axles, springs, and tires under E-450 so they can carry 20,000 pounds.

Safety is not like an on-off switch — as if at 9,599 pounds you are perfectly safe and at 9,601 you’re going to kill yourself and your family, and maybe take a few innocent people with you.

“Factor of safety” that professional engineers include in designs will take care of some overloading, but in the process the remaining excess capacity is diminished. Simply put, you are not “AS” safe 600 pounds overloaded as when load is within rating. Staying under ratings is even better, but that’s just common sense.

For what it’s worth, I have also personally seen broken frames and leaf springs. If some of you think a blown tire is a serious problem, it is not by comparison. Not even close. In my opinion having tires as the weakest link isn’t all that bad, because just about everything else that can fail from overloading is much worse.

I will admit occasionally having overloaded vehicles in the past, but would not intentionally overload a motorhome. If anything I prefer a lot of excess capacity, particularly since road conditions have deteriorated. My peace of mind is priceless to me, specially when far from home.
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Old 05-26-2021, 06:38 PM   #13
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Old 05-26-2021, 07:34 PM   #14
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All good info, thanks, I have been moving some stuff and taking a few things out. I will be reweighting it soon, take care all.
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Old 05-26-2021, 07:37 PM   #15
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Good luck!

My Missus wanted to remove 210 pounds of excess weight from our rig... she left me home!
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Old 05-26-2021, 07:38 PM   #16
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lol,,
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Old 05-26-2021, 07:43 PM   #17
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We were always pushing the limit with our Landmark

Decided the Tuscany would certainly fix the loaded weight issue and it sure did but because of the Tag axle

Springs and axles often get weakened by the pot holes and elevation changes in our road system

Same for for the frames

I agree on not running overloaded as a normal practice

Everyone should get weights and adjust as needed to be safer on the road
Quote:
Originally Posted by Chance View Post
Sh1t happens — for real. I have personally seen a few trucks with broken axles, and it’s not pretty. Axle itself isn’t the only problem, otherwise there would be guys on the internet advertising installation of Freightliner axles, springs, and tires under E-450 so they can carry 20,000 pounds.

Safety is not like an on-off switch — as if at 9,599 pounds you are perfectly safe and at 9,601 you’re going to kill yourself and your family, and maybe take a few innocent people with you.

“Factor of safety” that professional engineers include in designs will take care of some overloading, but in the process the remaining excess capacity is diminished. Simply put, you are not “AS” safe 600 pounds overloaded as when load is within rating. Staying under ratings is even better, but that’s just common sense.

For what it’s worth, I have also personally seen broken frames and leaf springs. If some of you think a blown tire is a serious problem, it is not by comparison. Not even close. In my opinion having tires as the weakest link isn’t all that bad, because just about everything else that can fail from overloading is much worse.

I will admit occasionally having overloaded vehicles in the past, but would not intentionally overload a motorhome. If anything I prefer a lot of excess capacity, particularly since road conditions have deteriorated. My peace of mind is priceless to me, specially when far from home.
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Old 05-26-2021, 07:43 PM   #18
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I personally have never seen or heard of a 5 year old chassis having an axle or frame break if it was 600lbs over. I have seen some rust buckets do that howver. I have also seen coaches at or below weight and have LT tires blow out for various reasons.... mostly weight and pressure.

I'm not saying people should overload any vehicle intentionally or dangerously but I am saying it is more important to focus the concern in the proper areas if you are going to be a little over weight.

The focus should be on tires first.... then springs.

Also... I may start out 500lbs over but by the time I burn fuel, water, propane, etc. I am typically under.

I have a TPMS and the Cross-Fire Dually Pressure Equalizers and Sumo Springs all the way around. My tires also rated for 22,000lbs. If I am 20,000 when I start a trip, I am not freaking out about being 500 over and then being at or under during the trip... but that's just me.
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Old 05-26-2021, 07:49 PM   #19
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I always run with empty water and sewage tanks; in order to save some weight...
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Old 06-02-2021, 07:11 PM   #20
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I ran a Harley in my 29h I was over axle weight but not my tires. So I wasn’t concerned. Add the max weight of the tires used as a duals and I came up with 9880lbs max. Your tires might be different but that’s the weight I am concerned with.
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