F250 Rear Axle Weight Rating with 20" wheels

Gdetrailer wrote:

Buck50HD wrote:
With the HD service suspension on the F250 and 20" wheels, it looks like it would have the same hardware as an F350 but wouldn't have the door/b-pillar sticker to match the true capability. I'd be OK with that.

The next big decision... gas vs diesel

Not necessarily.

ALL F250s (as of 2011 and up)max out at 10,000 lbs GVWR regardless of what tire or suspension.

F350s START at 10,000 lbs GVWR and go up to 14,000 GVWR depending on payload packages.

My understanding is that the axles ARE DIFFERENT between F250 and F350 (F350 having a slightly bigger axle shaft and such). There is more than what meets the eye when it comes to the weight ratings than just the tires.

The BASE 17" tires on a F250 ALREADY EXCEED the F250 capacity.

Do a search for the Ford towing guides and take a look at the chart for slide in camper. That chart will show you the max GVWR of the trucks...

Argue all you like, but I do have a 2013 F250 and I do have the stock 17" tires and they DO exceed ALL max weight ratings front and back. Combined of all four 17" tires comes in at 12,780 lbs on a truck which is max of 10,000 lbs GVWR...

If you "need" more tire capacity than 12,780 lbs then you WILL be overweight using a F250.

The idea that the F350 SRW axle shafts are larger in diameter is false. The idea comes from the erroneous publishing of Dually axle information in Ford literature years ago.

The SRW trucks all use axle assemblies produced at Ford Sterling Axle Plant in Sterling Heights, Mi. All units shipped to the Louisville Assembly Plant are identical...no specification differences for 250 0r 350 SRW truck builds.

The F350 Duallies all get Dana manufactured units with a slightly larger axle diameter.

Regards

Buck50HD wrote:
Thanks! Didn't think to look up this document. Now, I see why I thought you had to get 20's for a 7000lb RAWR. It's because the standard 18" A/S tires limit the rating to 6730lb and those are the only stickers I've seen. With the 18" A/T's, it shows 7000lb rating. So, with the camper package on an F250 and 18" A/T's, it's effectively 7k hardware, like the 350 but with a 6100lb sticker.

EDIT: another disclaimer... the guide shows the axle rating by itself is 6200 on F250 and 7280 on F350 so maybe there is a structural difference

Correct.

My F250 does indeed have 6200 as the rear axle rating.

The 17" tires gives 6,390 lbs so the stock 17" tires have 190 lbs MORE capacity on the rear axle than the actual axle capacity.

Therefore upping the tire size (18 or 20" on a F250 will do nothing other than draining your account when it comes time for replacement tires..

OP should be aware that diesel option will drastically eat into your cargo capacity on the F250.. So if you feel you are stretching the 17" tires think again, you will run out of cargo capacity...

Thanks! Didn't think to look up this document. Now, I see why I thought you had to get 20's for a 7000lb RAWR. It's because the standard 18" A/S tires limit the rating to 6730lb and those are the only stickers I've seen. With the 18" A/T's, it shows 7000lb rating. So, with the camper package on an F250 and 18" A/T's, it's effectively 7k hardware, like the 350 but with a 6100lb sticker.

EDIT: another disclaimer... the guide shows the axle rating by itself is 6200 on F250 and 7280 on F350 so maybe there is a structural difference

Use Fords spec sheets for '11 F250/F350 differences.

As mentioned Ford uses the 10.5" Sterling rear axle for these trucks. Ford gives it different RAWR depending on wheel/tire and the rear spring pack. The F250 does not have the F350 rear spring pack but may have the optional 18" or 20" tires and wheels. The optional 20" tires and wheel on the F250 with a 6100 RAWR gains nothing without the heavier rear spring pack.

Ford uses a 6100 RAWR for the F250/diesel.

Next up is the F350 SRW with a 6290 RAWR/diesel

Then F350 SRW with a 6730 RAWR/diesel

And finally the F350 SRW at 7000 RAWR/diesel.

Check out page 76 for the different rear spring rates and pages 61 thru 65 for the different RAWR numbers.

Other pages shows brake specs/front axle specs and other important features. Spend some time and check it all out.

This clicky leads to Ford pickups different year models.
https://www.fleet.ford.com/truckbbas/topics/techspec.html

Buck50HD wrote:
With the HD service suspension on the F250 and 20" wheels, it looks like it would have the same hardware as an F350 but wouldn't have the door/b-pillar sticker to match the true capability. I'd be OK with that.

The next big decision... gas vs diesel

Not necessarily.

ALL F250s (as of 2011 and up)max out at 10,000 lbs GVWR regardless of what tire or suspension.

F350s START at 10,000 lbs GVWR and go up to 14,000 GVWR depending on payload packages.

My understanding is that the axles ARE DIFFERENT between F250 and F350 (F350 having a slightly bigger axle shaft and such). There is more than what meets the eye when it comes to the weight ratings than just the tires.

The BASE 17" tires on a F250 ALREADY EXCEED the F250 capacity.

Do a search for the Ford towing guides and take a look at the chart for slide in camper. That chart will show you the max GVWR of the trucks...

Argue all you like, but I do have a 2013 F250 and I do have the stock 17" tires and they DO exceed ALL max weight ratings front and back. Combined of all four 17" tires comes in at 12,780 lbs on a truck which is max of 10,000 lbs GVWR...

If you "need" more tire capacity than 12,780 lbs then you WILL be overweight using a F250.

With the HD service suspension on the F250 and 20" wheels, it looks like it would have the same hardware as an F350 but wouldn't have the door/b-pillar sticker to match the true capability. I'd be OK with that.

The next big decision... gas vs diesel

EDIT: scratch that, can't get 20's with the camper package so the springs or tires will be the limiting factor on the 250, take your pick

I agree with Redsky above. The Sterling 10.5" rear axle used in the SRW 250 and 350 is rated for 9750 lbs. Running 245/70R19.5 tires will give you about the same 33" height as the 265/70R18 tire option. The 245/75R17 tires are about 31.5" tall. Going to the 19.5" rims and tires can get you over 4900 lbs of capacity per wheel based which tire you choose.

The axle and wheel bearings are rated at least to 8900 lbs. and possibly more. Subtract the weight of the truck at the rear and you have the maximum load capacity.

Stock rims and tires are going to be rated lower. Often the tires are rated at 3200 lbs. at 80PSI or less. Then you get 6400 lbs. with the two tires and that is your load limit unless you change the tires. Maximum load capacity will come from going to 19.5 rims and tires though that is going to cost over $3,000 to do.

Tire height figures can be misleading. If a tire is 2 inches taller in height it is only going to need 1 inch more clearance than the stock tire. If it is 1 inch wider the tire's inner clearance is going to be affected by 0.5 inch.

The OEM 20's are 2" taller, 34"dia. vs 32" dia. according to the Ford website. The rear axle rating won't change from the listed 6200# but because the axles are the same as that on the F350 SRW it's designed to a much higher rating.

I would verify that the 20" tires are truly bigger in diam than the stock 17 or 18" wheeled versions. I know in the past, 235-85, 265-75 -16's, are the same diam as 225-70-19.5, 265-70-17, the 245 and 235 width 17 and 18's ford and dodge were using are also 31.5" in diam, so no tire diam change in gearing per say, just a difference in rim diam and sidewall heights.

The brochure or online specs should state if the 20's are a different height overall than std.......of course, the wording is "SHOULD".........

Marty