truck overloaded?

For some reason, Light duty trucks are rated some 10-15% less than the sum of the axels. Meanwhile most medium and ALL heavy duty trucks, ie over class 4 trucks to class 8, will have the gvwr BE the sum of teh axels. This makes more sense to me. Now why the class 3 ie 1 ton/35 series and smaller trucks are derated.......your guess is as good as mine.

Meanwhile, if one wants to get into the legal side of things. A SW CC diesel truck with a 9900 gvwr, and a tare wt of 7500 lbs will be licensed for 12K here in Wa st, and it will be legal to run down the road at 12K lbs too! Door sticker be dammed! GCWR in most states, is also a non legal measure/rating. It is only from a warranty purpose that these ratings will be an issue. Along with a civil court case, but from an LEO stand point.....nada!

marty

Brakes are a function of the GAWRs. If the truck has 5k front and a 7k rear the truck has 12k of braking performance. Same with a trailer with two 6k axle = 12k lb of braking. The GAWRs on the truck is the truck manufactures rating which doesn't reflect the axle makers max ratings.

NHTSA says this about components of the GAWR:
"Gross Axle Weight Rating is the rated load-carrying capacity of an individual axle and wheel assembly. (It represents the load that may be steadily sustained by the components in the system; i.e., tires, rims, hubs, bearing, axles, brakes, suspension, sub frame, etc. with the GAWR limited by the components with the lowest working rating".

And from;
RMA

• GAWR: Gross Axle Weight Rating (for each axle) -
The maximum weight rating that the components
(tires, rims/wheels, brakes, springs, and axle) of
each axle are designed to support. This is
determined by the lowest design capacity of any
component. In other words, if the wheels have the
lowest design capacity of any component on that
axle, installing tires with a higher load capacity
does not increase the GAWR. By regulation, the
tire load rating times the number of tires on that
axle must equal or exceed the GAWR for that axle.

I doubt the OP is over the DRW trucks 8xxx ?? RAWR/4 tires as its carrying all the load

bucky wrote:
Maybe an engineer can explain why axle weights and GVWR don't add up, but I've never found anybody that could. Somebody mentioned tires as the limiting factor, and they are.

Not a mechanical engineer but my understanding is that it's the sum of the parts using the weakest link as maximum rating.

Axle ratings are max that the axles can handle
Gross vehicle is max that the weakest component of the total is rated for

Front axle has a 5000# rating, Rear axle has a 7000# rating but vehicle has a Gross Rating of only 10,000# because of the rating for brakes, tires, springs, frame etc.
Brakes probably have the lowest rating

SHifting down a gear on a hill SHOULD be expected frankly. Does not sound like you are having any issues with the truck to me. Everything is operating with in what I would call normal parameters! heck, My duramax shifts down a gear going up hills with 12K lbs.

Marty

I would be very surprised if the actual weight was even close to the GVWR. My 14,000lb loaded Jayco weighs 11,500 at the scales with a 2600lb tongue. You are doing the right thing taking it to the scales, I think you will be happy with the results. Maybe an engineer can explain why axle weights and GVWR don't add up, but I've never found anybody that could. Somebody mentioned tires as the limiting factor, and they are. However, on a dually you are going to have about 12,500lbs of carrying capacity and tongue weight is subtracted from actual weight to get your sprung weight. You'll be well within limits there.

mdamerell wrote:

Looks like you are ok on truck payload but over on your gross vehicle. 20,000# GVWR and you are probably around 22,000# based on what you posted.

That would be gross combined rating (truck/trailer) GCVWR...........not GVWR

According to that tow guide.......only has a tow rating of 12,500# (20,000# combined gross) with auto tranny
And a tow rating of 10,700# (17,000# combined gross) with manual tranny

Hummmmmmmm.....seems you are over by 1,900# or by 3,700# depending on tranny

1995 Ford Tow Guide

This may help.

If it bothers you that you are touching or resting on the overload springs you might consider a set of air bags. Before my air bags I was a 1/4" off the overload springs and would get a 2nd bounce now and then when I hit a bump. A set to Firestone Ride-rites gave me some extra clearance and helped my ride.

Looks like you are ok on truck payload but over on your gross vehicle. 20,000# GVWR and you are probably around 22,000# based on what you posted.

If it helps, my trailer (in signature) is 12,000# actual (14,000 GWVR) and pin about 2,600# (22%) my F350 (with us and 39 gal fuel) is about 8,400#

yeah we never camp far from home anyway. about the furthest we go is about an hour from home. and once you get on a straight stretch of road it is fine it is just when you are going up and down the hills that I will have to go down to 3rd gear. also just realized that the 14303 was with the factory installed generator that someone took out before we got it so the real weight is around 14000lbs. thanks am going to get it weighed this weekend.

it is a DRW-iwould rock on!-whsk

lspencer wrote:
ok thanks. it is going to the scales on friday on the way to the dealer for warranty repair. when hooked up it squats down 2" and just comes to rest on the overload springs. both the front and rear axle add up to 11800lbs when you add them togegher.

GVWR is NOT the sum of front & rear axle ratings....it is less
Look for sticker in glove box, on door sill, edge of door
IT will have FAWR, RAWR & GVWR
GVWR will be around 10,000# for that year of truck