Hi folks, I know this topic has been discussed many times here but I am going to bring it up again anyway...payload capacity.

According to my door placard, my truck has a GVWR of 6,100 lbs. Based on what I've read, I should subtract the wet curb weight of my truck (about 4,400 lbs) from the GVWR to calculate my payload capacity of 1,700 lbs.

First of all, is this correct?

Why do the front (2,700 lbs) and rear (3,776 lbs) GAWR added together equate to more than the GVWR at 6,476?

I've been to the rock quarry several times when they gave me more than I asked for. In those cases I have made it home with 2,500 lbs in the bed. Am I just lucky, or are the payload capacities conservative?

I have a few more questions, but I'll save them for later...

 

Yes it is.

Other systems(brakes, transmission) may not be rated for that much load.


Yes they are conservative, the ratings are set at a load the vehicle can reliably carry again and again for the life of the vehicle and not cause any damage or excessive wear. As you have found out you can exceed those ratings but that is something you should not make a habit of doing, luckily you probably didn't exceed the rear axle rating too which is good, that would have been a gross overload.

 

Conanski nailed it.

 

The big limiting factor on these trucks from the standpoint of hauling loads, IMO, is the brakes. The front and rear ratings on your sticker are only talking about what the axle and springs can take. Also those ratings are based on the factory tires that came with your truck, which are long gone (I hope). So you also need to think about what is the max load of your current tires.

 

This is where I was heading with my next questions... I put new tires on it about three years ago (I'll reply with the details when I get home from work) and they are good tires with 3-ply sidewalls. So the tires aren't a limiting factor.

I am wondering if I replace my worn-out leaf springs with higher capacity ones, would that effectively increase my payload capacity? What would the next weak link be...the axle?

 

In a technical sense you can upgrade the the weak links in the system to increase capacity but you will never increase the legal carrying capacity over the OEM rating.

To my mind, when you go after these kind of upgrades you are just better equipping the vehicle to handle max load, not actually increasing max load.

The system will only be as strong as the weakest link, and the rated capacity reflects this. I would think the AOD transmission would be a weak link, as well as worn springs. Ring and pinion ratio will be involved as well. The frame, brakes, and engine should be good up to the max ratings of an F150 (same wheel base/cab combo) of this vintage. Assuming everything is in good shape of course.

An issue you are not considering when hauling heavy loads in the bed in the strength of the bed, and the forces exerted on it by an unsecured load in motion.

If you are regularly maxing out or exceeding the capacity of the truck my advice would be to buy a truck with more capacity. It will be easier and safer for you, other folks on the road, and for the truck.

Alternatively, buy or rent a trailer. You can always tow more than you can haul in the bed.

 

R&RFord raises a good question - how often do you intend to haul at capacity?

 

You can bolt in a F250HD/F350 spring pack.It will raise the rear of the truck and you'll need to get an alignment.After this,the truck will carry a lot of weight without squatting but eventually the axle will say uncle.
This is what happened to me after I upgraded the spring pack.It took a few years of carrying a ton or so before it locked up though.
If you need to carry 2,500 lbs then it's time for a HD truck.The F150's are just too light duty for this kind of use on a regular basis.

 

I would really just like to be able to haul 1 ton (2,000 lbs) short distances on the weekends. I've already done so with worn springs, and I think a simple upgrade to the rear suspension would allow me to do this.

It really seems to me the weakest link in an F150 versus a light duty 3/4 ton truck are the springs. Correct me if I'm wrong, but the 5.0 and AOD were available in F250s and F350s. I'm not sure about the rear axle on the 3/4 trucks, but I would guess the 9" was available on them as well. So the same drive train should be able to handle an extra 500 lbs...

Would you recommend new spring packs over helper springs/add-a-leafs w/ the original spring packs? I'm guess I should replace the shocks too. I probably won't mess with the front though.

 

Sounds like you need a 3/4ton+ truck if you plan on hauling 2000lbs on a semi regular basis

 

The reason why Brad is correct is not simply because of the springs but when you get into the F250 light duty,you get a semi floating rear axle too.When you get into the F250/F350 platform,you get a full floating rear axle.
This takes weight off the axles and puts in on the bearings.You also get a thicker frame and larger brakes are you go up as well.
I hauled over a ton almost daily with an F150 for a few years back when just starting out.Sometimes ya gotta make due with what ya have,if you want to live debt free.
That said,you should really consider a heavier duty truck as soon as you can.If your just going short distances,then just go ahead make two trips of it.

 

The 9" was never installed in a 3/4 ton... even the old light duty 250's had a heavier Sterling non-floating axle.

I'd look at installing a set of Timbren overloads... they work good, keep the ride nice and are pretty affordable. The weak link is still the rear axle but if you don't abuse it you should be ok.

 

What are the f150s rated to tow? specifically an '89 model. I don't seem to have a placard on my truck anywhere stating the load capacitys and ford Australia no longer have the info.

 

not sure about 1989 F150 but 1991 F150 towing is 2800kg

 

Awesome, cheers gmw67.