Ford F350 DRW v. SRW?

[JerryHooper]

We've got a 2011 Ford F350 4X4 CC DRW LB King Ranch with no alterations and use a Hensley TS3 hitch. According to the tow guides, we're good to tow 21,500# while the same model in a SRW shows a max tow of 15,700#. Can someone tell me what kinds of alterations might be made to the SRW that allow it to pull what appears to be the comparable weight? Does anyone have any experience that supports one model vs the other?

Thank you!

[Cummins12V98]

How about rear dual wheels?

[wandering1]

Read the Ford tow specs from Ford and see what is different for the configurations. I haven't seen any ford engineers on the forum.

[Gannet]

I'm sorry, I'm not following this. You want to tow 21,500 with the SRW? Don't. Use the DRW or get a smaller trailer. If they could have done that big a tow rating with the SRW, they would have. To say nothing of the fact that a DRW will be much more stable hauling a large trailer, capacity aside.

Specific differences are likely the rear axle model, gearing, tire capacity, and quite possibly others such as cooling system. Tow vehicle capacities are based on all the systems, and they tend to upgrade everything as needed, which is another way of saying that they tend to not include "extra" capacity in systems where it isn't needed. Doing so wastes money, which they hate.

[SmokeyWren]

Originally Posted by JerryHooper

We've got a 2011 Ford F350 4X4 CC DRW LB King Ranch with no alterations and use a Hensley TS3 hitch. According to the tow guides, we're good to tow 21,500# while the same model in a SRW shows a max tow of 15,700#.

First, let's correct your tow ratings. Assuming a diesel engine with 3.73 axle ratio, the DRW is rated to tow a tag trailer weighing up to 17,500 pounds, while the tag trailer is rated to tow a tag trailer weighing up to 14,000 pounds. (The 21,500# is for a fifth wheel trailer, not a tag that would use a Hensley Arrow hitch).

Can someone tell me what kinds of alterations might be made to the SRW that allow it to pull what appears to be the comparable weight?

The answer to that specific question is that the "conventional towing" or tag trailer tow rating is limited by the weight rating of the factory hitch receiver. Assuming a diesel engine, the receiver on a DRW is rated 17,500 pounds max trailer weight, while the receiver on the SRW is rated 14,000 pounds.

If you replace the factory receiver with one that has more weight rating, then you can use the fifth wheel tow ratings as your max.

In any case, the GCWR of the tow vehicle is the base number to determine tow rating. The SRW has a GCWR of 23,500, while the DRW has a GCWR of 30,000. What's the difference in those two trucks that would allow one to gross 6,500 pounds more GCWR than the other? Ignoring the obvious difference of dually vs. SRW, the other differences affecting GCWR and tow rating are primarily the rear axle. The rear axle in the DRW is a Dana 80 with 11.25" ring gear and 3.73 ratio, while the rear axle in the SRW is a Ford "Sterling" axle with 10.5" ring gear and 3.31 or 3.55 ratio. Big difference.

Subtract the weight of the wet and loaded truck from the GCWR of the truck to get the actual tow rating of the truck. There is 6,500 pounds difference between the SRW and DRW GCWRs, but the difference in tow ratings are less because the DRW weighs more than the SRW.

Does anyone have any experience that supports one model vs the other?

The GCWR and tow rating are not the limiter for the SRW truck. If you try to pull a trailer that gets close to the GCWR or factory tow rating of an SRW truck, you'll be severely overloaded over the GVWR of the truck. Ford says you should NEVER exceed the GVWR or GCWR (or any other weight limit, such as the receiver hitch weight limit) of your tow vehicle. On an SRW truck, the GVWR will be your limiter as to how heavy a trailer you can tow without being overloaded.

In other words, hitch weight matters on an SRW, but not so much on a DRW because the DRW has a lot more GVWR than the SRW.

L8R,

[SmokeyWren]

Originally Posted by SmokeyWren

Assuming a diesel engine with 3.73 axle ratio, the DRW is rated to tow a tag trailer weighing up to 17,500 pounds, while the tag trailer is rated to tow a tag trailer weighing up to 14,000 pounds.

Sorry about the obvious typo. I had to run take care of a honey-do, and when I got back it was too late to edit the post. What I intended to write was:

"Assuming a diesel engine with 3.73 axle ratio, the DRW is rated to tow a tag trailer weighing up to 17,500 pounds, while the SRW with 3.31 or 3.55 ratio is rated to tow a tag trailer weighing up to 14,000 pounds."

[wingnut60]

The Hensley TS3 is a 20k fifth wheel hitch...
Joe

[SmokeyWren]

Originally Posted by wingnut60

The Hensley TS3 is a 20k fifth wheel hitch...
Joe

Oops! then throw my posts out the window.

[2500HD]

Are you asking because you want to go back to a SRW?

[JIMNLIN]

Can someone tell me what kinds of alterations might be made to the SRW that allow it to pull what appears to be the comparable weight?

Not really a good idea.
The 350 SRW has a 6290/6730 or 7000 lb RAWR with two tires that will carry the pin weight. These trucks are limited to 3500-4000 lb at best for a payload depending on cab selections. This will limit the trailers GVWR to around 15k-16k lbs and 3200-3400 lbs of pin weight.

The 350 DRW has a 9000 lb RAWR and four tires carrying the trailers pin weight. These trucks can carry up to 5500 lb payload depending on cab selections which can handle 21500 lb trailer pin weight (4300-4500 lbs.

Smoky gave you the trucks specs on the mechanical differences.

You would have to change out the 350 SRW trucks complete rear axle/suspension/brakes/shock mounts/etc to the 350 DRW complete assy. However this doesn't change the trucks GVWR/FAWR/RAWR certification tag which can lead to registration issues in your state.

The big downside of pulling a 20k trailer with any SRW truck is the heavy trailer pushing the back end of the truck around especially on curvy wet roads. Huge safety issue.

[bailiff]

Just a little experience. Not that much weight but experience just the same. I bought a 2004 FR Sandpiper new leftover in December 2005 with a GVWR of around 12,000. I was told the pin weight would be about 1,100 so I started with a 2006 F-250 a SRW truck. The truck always acted funny wanting to sort of wag and the chucking, for and aft shaking on concrete pavement we terrible. After a long trip to Maine, I had had enough. Bought a 2007, F-350, 13,000 GVW and DRW with 4:10 rear. The difference was night and day. I also had the trailer weighed. I had 3,300 lbs pin weight and 8,800 on the axles. The remainder of our ownership and travels was sweet.