How big of a deal is it if the rear axle track width is narrower than the front? Would there be a big handling issue at all?
The truck is a 1985 cab and chassis DRW 4x2, with the long wheelbase.
I'd like to swap to singles and ditch these duallies, I'm sick of the lack of traction floating on top and having to pay more for 215/85R16 tires.
This truck has an 11' bed. I bought it to use the bed space because lawn care equipment doesn't weigh a lot, it just takes up space. There's no need for the duallies to handle the weght of lawn mowers, so it's time to save fuel and ditch the two extra tires.

My cab and chassis rear axle has an approximate WMS measurement of 65". I have an extra axle off the truck I was able to measure.

The front end measures approximately 75" from the outside to the outside of each tire.
The 235/85R16 tires have an approximate tread width of 9.5", meanng 4.75" in half.
Theoretically, the cab and chassis rear axle with 235/85R16 tires would be 74" ONLY IF the rims bolted exactly centered in the tread width.
My goal is to buy some Wagon Wheels, the classic 8-spoke wheels, but I'm struggling to find a backspacing measurement.

I'd like to keep my axle under the truck, and avoid buying a SRW axle and paying a welder to weld on new spring perches to fit my springs...
I have a set of '78 K20 GM axles I acquired to resurect my '65 F350, it's a Dana 44/GM 14 Bolt combo. The front is approximately 69", and the rear is approximately 66". I never drove the truck, so I'm not sure how it handled.

Anybody have an opinion on the track width difference? I want to do the right thing, that way the truck is fully capable of handling weight if I do have to haul some weight. My Dad's '03 F350 SRW handles a huge slide-in truck camper like a piece of cake, so I've become skeptical of why DRW's are even necessary...

 

FYI: some Chevy 2500's (forget years, late 80's-90's) came from the factory wider in the front. Can't see where there would be a prob.

 

Yes, the '90s 4x4 IFS 3/4-ton and 1-ton Chevy trucks are much wider in the front than in the rear, and this is the factory setup.

For what you wanna do backspacing itself don't matter much, you need to look at it with relation to wheel width, you're looking for wheels with zero offset meaning the backspacing is half of the wheel width. The factory steel single wheels are zero-offset 7" wide IIRC, so those would work for you good. If you want wagon wheels for sure, take a look at these on Summit Racing:

U.S. Wheel 70-7780 - U.S. Wheel 70 Series White 8-Spoke Wheels - 4" backspacing in this case means they won't be perfectly centered on the hubs but sit 1/2" further in per wheel making for an inch narrower track width, but that won't be much of an issue as the SRW trucks have a slightly narrow rear track from the factory. 7" wide wheel is good for 235-wide tires.

 

cab and chassis drw and regular single rear wheel trucks had the same width rear end. just different spring perch placement

 

True that! Also to switch the fronts to singles all that's needed would be a pair of singles-specific hub-rotor assemblies...

 

yeah i forgot about the front

 

That's the nice thing about it being a 2wd truck - were it a 4x4 things could get much more interesting.

 

its really the same thing for 4x4

 

Not quite, the dually 4x4 trucks of those years have dually-specific front hubs, you need to switch those out for SRW-specific front hubs - SRW 2wd hub-rotor assemblies you can buy at any parts store, not so much the case with SRW 4x4 hubs.

 

Thank you for the link to Summit, those are definetly the wheels I've been dreaming of since I was 6 and fell in love with the ones on my Dad's Jeep!
I followed your link, and found 16x8 8-luggers. I learned through the Cooper website that an 8" wide wheel will accept up to a 265 wide tire, which is perfect because I want to run 265/75R16 tires with a load range E.
The 16x8 wheels have a 5" backspacing, which puts them in the same track width as the 16x7 wheels.
Actually, the Ford/Sterling axles come in 3 flavors: Cab and Chassis DRW, Pickup DRW, and Pickup SRW.
The Cab and Chassis axle is set up for 2.5" wide leaf springs, and a 34" wide frame. It is the narrowest axle housing of the 3.
The Pickup SRW is the middle in terms of width. It's set up for 3" wide leaf springs, on a 37.5" wide pickup chassis.
The Pickup DRW is the widest. It's also set up for 3" wide leafs on a 37.5" wide chassis.
The reason the Pickup DRW axle exists is because the SRW axle can't accept dual wheels because the inner wheel will hit the leaf springs as far as I've read.
You're right on with the fronts! I'm planning on pulling the entire I-Beams off a 2wd F250 donor and installing new king pins, bearings, give them some paint, and just doing an overhaul before installing the entire assemblies with new bushings.

 

Actually IIRC the SRW pickup axle is just as wide as the dually cab-chassis axle as far as WMS distance goes - its the distance between the backing plates that is different (due to how offset the cab-chassis drums need to be to accommodate the dually wheels), and like you mentioned the spring perch distance cause of the frame width.

And I was thinking of linking you to the 16x8 wheels too, but decided against it since the 265-wide tires are more expensive than the 235s and you wanted 235s cause they're cheap and plentiful, lol. You gonna run 265s on the front too?

 

Ok, I understand what you mean now. The last time I was measuring, I was measuring backing plates and WMS and I got facts mixed up. Thanks for the straightening out!
I was thinking 265's because I'd like Cooper Discoverer ST-C's for the rear and Cooper Discoverer H/T's for the front. They're load range E and have white letters on the sidewall. I'm a sucker for white letters on the sidewalls!
I've been searching the 'net pretty widely for the last few months, looking for different commercial traction tires. I'm hooked on these Cooper Discoverer ST-C's for the nice tread and the specs say it's a hard type of rubber compound, perfect for the rough terrain and sharp rocks on the farm. A highway tread on the front is fine, as they are not driving tires.
235's are a nice size, but I'm not finding them with white letters on the sidewall.
Yeah, I know...spend a lot more for tires just for white letters seems pretty lame. But they'd be the first new set of tires I've ever bought!

 

SRW rotors...
Can we talk about light duty versus heavy duty F250's for a minute?
Napa online has differences between the under 8500 GVW and single-piston caliper rotors and over 8500 GVW and dual-piston calipers.
Are we sure the F250 rotor will 100% positively bolt onto my F350 spindles?
Or can I order 87+ F350 SRW rotors?
I'm going to order my rotors tomorrow or Monday, and want to be sure I order the right rotors.

 

Aint the SRW F350 rotors and the HD F250 rotors the same? Thought they were... Also never actually seen a LD F250 with a diesel, besides them brakes are smaller anyways.

 

the D50 SRW 4wd hubs are said to be a direct swap for a D60.
i would just hit the salvage yard for a pair of these common gems.
you'll want to grab the brake rotors too if they look good.if not get some new ones.
the D50 and D60 SRW brake rotors should be the same.check the part #'s to see for sure.if their not (in the same year anyway) id be stumped lol.
anyway,if your buying new,why wouldn't you just tell the sales guy you want a pair of rotors for a SRW f350 and keep it easy.then you wont even be asked between under or over 8500 gvw,and save the dance lol.