Just purchased a 2013 Ford F350, SRW, LB, 2WD, 6.7L diesel, 3.31 axle ratio. We chose the 350 over the 250 (was very little difference in cost) because of the increased rating of the rear axle. (GRAWR). The brochure we were given and I also saw the same info at ford.com show the rear axle rating for 350 as 7180 lbs. For the 250 as 6290 lbs.


Now the problem. Maybe not a problem but just confusion on my part. The "safety compliance certification label" on the door jamb which lists the different ratings as required shows the RAWR for my F350 as 6290 lbs which is the same rating for the F250. Also indicated a max payload of 3428 lbs. and for a 350 it should be 3740 lbs. (i think, don't have that in front of me right now).

tires are load rated at 3195 lbs.

Any 2013 F350 owners with cert labels that read RAWR = 7180 lbs or do they all say 6290 ??
What gives? Any feedback will be appreciated. Would like to have a better understanding when I go back to the dealer. Have owned the truck for 2 wks.





Thanks

 

Hi abqm,

The rear axle is rated for 7,280 lbs, but your tires and wheels may not be. The GAWR on the door sticker has to match the weakest link in the chain, which in your case is the wheels and tires.

If you have 17" wheels they are only rated for 3,195 lbs each, so you exceed their capacity before you reach the max capacity of your axle. Here is the door sticker for my 2011 F350, it has the same 6,290 lb rating.

 

just checked on truck in my sig, its 7180 lbs ,
granted its a 2012 model
18" wheels

 

Then if I replace my tires with higher load rating tires then I'm good up to the load rating of the new tires but not to exceed the axle rating? And I can assume the axle rating is 7180 per the brochure.

Then my sticker is only accurate with the specified tires, which makes sense, I guess.

 

Not exactly, this is what I posted about above. If you have 17" wheels it's not just your tires; your wheels are a limiting factor with only being rated for 3,195 lbs. To achieve 7,000 lbs without going over the limitations of your hardware you'll need new wheels as well. See below:

 

Dang - now you are making me go look at my new 11,500 lb gvwr 350 sticker !!!!

be back in a minute

Crazy - can you make your attachment (pic) smaller ?

on edit - here's my sticker and now I feel better
to the OP - IIRC, the f-350 had like 10 different GVWR's depending on configuration... so maybe you gvwr is not the highest ?

like on the 10k gvwr f-250 I just traded in because the rear axle wgt rating was only 6200....

 

The RAWR for a F250 and a SRW F350 should be identical.

The RAWR for a DRW F350 will be higher.

No math is done on the door sticker. The number on the sticker is an indication of the weakest link in the axle assembly (brakes). It is your own responsibility to pay attention to the weakest link (RAWR, Wheels, Tires).

 

This is incorrect, the brakes are identical between the SRW trucks, yet the GAWRs are vastly different depending on configuration. The max GAWR for an SRW F350 and F250 are different by nearly 1,000 lbs, but to my knowledge the axle is identical.

https://www.fleet.ford.com/truckbbas...Pickups_SB.pdf

 

4. Gross Axle Weight Rating is determined by the rated capacity of the minimum component of the axle system (axle, computer-selected springs, wheels, tires) of a specific vehicle. Front and rear GAWRs will, in all cases, sum to a number equal to or greater than the GVWR for the particular vehicle. Maximum loaded vehicle (including passengers, equipment and payload) cannot exceed the GVW rating or GAWR (front or rear).

Other than the fact that there are proven inaccuracies in that book, it looks like they changed it. Wheels and tires should not be included in those numbers because they change too easily, and it seems they've started using different spring packs for different configurations. (so they can use different spring packs, but a real transmission is too much variance?)

from the footnote quoted above, the spring and spacers would be included in the rating which is likely where the variance comes in. Once the spring packs get big enough, it appears the brakes become the limiting factor again.

 

Did you know that your VIN is still readable?

One word Barcode.

Sean

 

It seems like you are selectively processing information to support your point. Nowhere does it say anything about brakes, but it does state wheels and tires. See below, EVERY F350 and some F250s have spring packs that are rated at 7,000 lbs, but trucks like the OP's(and my '11) had rear GAWR less than that.

The springs are the same. The brakes are the same. The difference is tires and wheels which(See HERE) are rated for less. Demonstrates pretty clearly that wheels and tires are the limiting factor. Heck, the footnote that you quoted even states that.

And that's the same across platforms for many years. My 2000 MY Excursion has a 7,000 lb axle, wheels rated for 3,415 each, tires rated for 3,500 each, and springs rated for 5,250 lbs. The weakest link here is the springs, and that's why my rear GAWR is 5,250 lbs on the door sticker, even though I have the same brakes as a SRW F350.

 

Except the wheels and tires generally are rated for more than the RAWR.

The difference in most is the spacers. While the springs have the same k value, a taller spacer allows for more deflection before the axle height leaves the designed operating range (no, riding on the bump stops is not what they are designed for). This can be seen in the "Combined Rating @ Ground" above. With taller spacers, "ground" is a greater deflection, and thus greater force (F=kx)

I admitted that Ford, for some reason, says they include wheels and tires, but I doubt that they are ever the limiting factor unless they have been replaced with insufficient parts.

By the way, are you claiming that brakes are not part of the axle?

 

thanks for the help, guys. when sitting with the sales guy and selecting options I chose 17" wheels vs. 18" wheels not knowing the impact. Guess he didn't either but buyer beware.

Still, I like the truck and guess we'll be happy with it.

 

The good thing is how easy it is to upgrade in the event that you want the higher capacity. A set of wheels and tires is much less expensive than a new truck. Of course the weight police are probably gonna chime in about how there's no legal way to increase the weight on the sticker.

 

can you simply replace 17" wheels with 18" wheels without creating other issues?