F250 Rear Axle Weight Rating with 20" wheels

My 12 F250 Lariat Extended Cab Diesel with 20" wheels door stickers say:

GVWR: 10000
Front axle GAWR: 5200
Rear axle GAWR: 6100

Payload: 2332

Bret

The F350 rear GAWR gets de-rated to 6290 when you select the optional 17" tires/wheels because of the max capacity of the 17" tires/wheels.

The axle shafts on our full floater rear axles do not carry weight. Weight from a TC is carried by the two bearing in end of each axle tube in the axle housing.
They simply simply pass the twist (power) action along to the tires as in a tow rating. As we all know the F250/F350 have the same tow rating depending on truck selection so I wouldn't worry about axle shaft diameter or the 35 vs 37 axle spline difference for carrying more weight.

Now Ford has a 6100-6200 RAWR in the F250 and a 6290 RAWR package in the F350 series which adds more mystery to the different axle shaft sizes and RAWR numbers.
IMO this is where having a nephew that works in a Ford truck dealers parts department would be a good idea..... if it means anything.

BlindGuynAR wrote:
Axle housing and shafts are the same between f250 and f350

Part#'s are the same for axle shafts and axle housing here are part#'s

The housing is part # BC3Z*4010*D the driver axle is BC3Z*4234*C and the passenger is BC3Z*4234*D look them up. Tasca

They are the same between 250 and 350. The info on them being larger is wrong or there would be diff part#'s plain and simple.

Like a previous poster said there are those that will never believe so it's a waste of time to try.

That's also what I found after talking to the Parts manager from our dealership (he's my neighbour) and after talking to a hockey buddy that is an SGI insurance adjuster he had a look and confirmed it as well

Axle housing and shafts are the same between f250 and f350

Part#'s are the same for axle shafts and axle housing here are part#'s

The housing is part # BC3Z*4010*D the driver axle is BC3Z*4234*C and the passenger is BC3Z*4234*D look them up. Tasca

They are the same between 250 and 350. The info on them being larger is wrong or there would be diff part#'s plain and simple.

Like a previous poster said there are those that will never believe so it's a waste of time to try.

ok, ran across a few more points from the 2014 Ford documentation

6.2 rear end has 2 spider gears, 6.7 has 3 (doesn't say 250 or 350, only by engine type)

350 does have more splines and larger diameter shaft (but the DRW has smaller dia shafts than the 250, but different manufacturer?)

Brakes are hydro only with the diesel. Doesn't matter 250 or 350. The 6.2 has vacuum in either 250 or 350.

F250 camper package spring pack appears to be identical to one of the 350 packs with 7k rating

outer bearings appear to be the same

Buck50, good luck with your decision.:)

I'm certainly not trying to turn a 250 into a 350, just trying to get the facts straight and get a SRW axle with the highest possible rating, regardless of the sticker value.

Ratings are not absolute values. Take for example my F150HD payload of 2171 lb. Someone can go out and buy a standard F150 with no options, 2WD, reg cab and have more payload. But I guarantee if you hooked my 5th up to it, the towing experience will be nothing like the HD payload truck with the stiff suspension and E tires. Just like a 250/2500 with 2000 payload will certainly handle my 5th better with improved safety when compared to my F150HD with 2171 lb rating.

The above info certainly helps although if the housing, spindles and bearings are the same then, being a full floater, the axle shaft diameter won't make much difference. All it's doing is transmitting the drive torque which is no different between the two models. I'd like to think there are other details missing here.

I thought the axle in my F150HD had something significantly better than a base axle but after more reasearch, my opinion has changed. The bearing in the parts book is identical, which is the primary reason I have some concern with it. The housing does have a different part number so the thicker wall tubes may be a fact. As far as the axle diameter and/or design, there may be subtle differences that could dramatically increase ultimate and fatigue strength.

Keep it coming. I don't like to take things for granted and would like to confirm.

8iron writes “The point is that with certain option packages, mechanically it IS an F350. IF one chose to, one could exceed payload rating with an F250 and not exceed a single design rating of any component under that truck.”

It took me a while to locate the info BUT you guys are wrong, you are only fooling yourselves.

The F250 while it does use a 10.5” Sterling axle HOUSING, the axle of a F250 is NOT the same INTERNALLY as a F350.

The internal axle is not the same size (kindly notice that the 1.36” minor shaft size of a F250 is SMALLER than the 1.5” minor shaft size of a F350), the diameter over the splines is ALSO different (F250 is 1.50” and F350 is 1.57”) which means the internal parts are not the same and who knows what else is different internally..

There is good reason as to why a F250 axle shaft has 35 splines vs F350 which has 37 spline. Try putting a fitting 37 spline shaft into a 35 spline carrier, not going to happen. And for a good reason, the shafts are different size and have different capacities and so will other internal parts..

I guess I am only one of a few folks who have noticed these differences…

I would bet that if you ordered F350 internal axle parts that they would not fit into a F250 axle without changing every internal part..

Please note in the quote below that a F250 AXLE is rated at 6200 lbs and a F350 axle is rated 7280 lbs (spring and axle ratings ARE GIVEN SEPARATELY)..

If what you say is correct then why is the AXLE RATED DIFFERENTLY between F250 and F350?

Why would the F250 have 35 spline vs the F350 with 37 spline?

If what you say is true then BOTH F250 and F350 would have the exact same axle rating AND the same number of splines AND the same axle diameter. NONE of that is true.

Pretty much stands to reason, Ford like any other manufacturer is simply not going to spend more money than needed. Bigger, heavier internal parts COST more and there is no sense putting those in a vehicle unless they are really needed. If it was not so then Ford would have no reason to even build a F350, they could just use one heavy duty truck with different tires. If it was as simple as you say then Ford would simply slap a F350 sticker on any truck.. But they don’t.

Same goes for the springs, if one is observant you will notice that there ARE different springs with different number of leaves IN THE PACKS.

The simple answer is NO, you cannot make a F250 into a F350 by upgrading the tire size, you really would have to CHANGE THE AXLE AND SPRINGS along with the upgraded tire along with any other suspension parts which are not the same. The cost of aftermarket parts would far exceed the cost difference between a F250 and F350.

The body, frame, engine, transmission, interior may all be the same between F250/F350 but the suspension parts is not the same.

I think what confuses folks is the order/axle codes are the same and the PHYSICAL OUTSIDE DIMENSIONS are the same but I guarantee if you slip under some new trucks on the lots and write down the axle PN tags of a F250 and F350 you will find completely DIFFERENT Ford part numbers on those tags.

If you need the higher capacity of larger tires (remember the default 17” tire has 3195 lbs of capacity) then you NEED to buy a F350 and be done with it instead of pretending.

If ride height is an issue then changing the rear blocks will drop a F350 down to a F250 ride height however keep in mind that you may need to rework the drive shaft angles.

F250/350 Comparison

From the link above..

"Here is some info I posted in some other forums, I pulled the info straight from the factory fleet manuals from the ford site.

2011 Model Super Duty
F250 SRW"Sterling" axle rated @ 6200 lbs___springs rated @ 6100 lbs--axle shaft dia 1.36"min - 1.50"maj - 35spline__brakes--13.39"

F350 SRW"Sterling" axle rated @ 7280 lbs___springs rated @ 7000 lbs--axle shaft dia 1.50"min - 1.57"maj - 37spline__brakes--13.39"

F350 DRW"Dana 80"axle rated @ 9000 lbs___springs rated @ 9000 lbs--same as above__brakes-13.39"

F450 DRW"Dana 80"axle rated @ 9000 lbs___springs rated @ 9000 lbs--same as above__brakes-14.53" front - 15.35" rear

F250/350/450 front axle rated @ 6000 lbs for 4x4 - 5250 lbs for 4x2 -- all brakes above are rear sizes front are 13.66" except F450

The actual axle housing diameter is the same 3.5" on SRW 250 AND 350. 4" diameter on F350/450 DRW."


F250/350 spring comparison

Text from above link..

"2011 F250/350 Leaf Spring Question
Oh guys, first real post. I'm interested in finding out some info. Ford Engineers stated that the reason they went with a 2+1 rear leaf spring design on the 2011 Super Duty was to reduce weight, improve the ride. Upon researching the various Super Duty's I've seen the following.

First, when I purchased my 2011 Lariat F250 6.7, the sales person said the only difference between the 250 and 350 was 1 extra leaf spring (2 total). However, i'm finding out some interesting facts.

First, I've seen at least 5 2011 F350 (Crewcab) trucks (all Lariat models) that have a 2+1 (3 total) Leaf Spring setup.

I have also seen at least 4 2011 F350 (Crewcab) trucks (all XLT, some with Gas and some with Diesel) with a 3+1 (4 total) Leaf Sprint Setup.

And of course the straight frame F350 has something like a 9 leaf setup.

So, why do the F250s have a 2+1 Leaf setup as well as the F350, and some XLTs have a 3+1 while lariats have a 2+1.

Also, is the spring rate the same? are they stiffer on some trucks?

NONE OF THE TRUCKS LISTED ABOVE HAD THE FACTORY OVERLOAD SPRING ON TOP. There are all part of the regular leaf stack."


Another F250/350 comparison

Text from above link..

"Package for package, tires for tires, wheel base for wheel base the trucks are identical. The main difference is the gross vehicle weight, the small differences for the F350 SRW, a spacer block under the rear axle spring pack, larger diameter rear axle shafts with finer splines, rear helper springs, and hydro-boost breaks, Price. Again, package for package, tires for tires wheel base for wheel base, gear ratio for gear ratio, the ride and fuel mileage will be the same."

Ignore the facts and continue on dreaming that a simple tire change makes a F250 into a F350...

Buck50HD wrote:
Thanks for the additional info. The main reason I'm trying to avoid the 350 is the 2" additional height. It's going to make my 5th ride even higher in front. I'd rather not have to wrench on the truck as soon as I get it but I could swap the rear blocks and change front springs. The 350 doesn't concern me for any other reason and is likely the way I'll go if diesel.

Yes, that would be an issue with the 4x4. The 350 4x2, in all cab/box configurations, is basically the same as the 250. Since you currently have a 4x4, I would assume you are looking at the 4x4.

Buck50, if you are looking at getting a diesel, I would buy the 350 over the 250. I have a 250 gas, 9900 GVWR and have a 2415 LB payload. I do have a Lariat so it does have a few options that contribute to that. The diesel will probably take you down to a payload to about what you have with your F150. Looks like you already thought about that.

S