Originally Posted by Lilnuts2
You might consider getting slightly heavier front coils. With the added weight of the new axle the increased inertia will use more suspension for the same size bump compared to the 2wd front end.
It's my understanding the POR15 can chip badly (because it's so hard) when driven on gravel roads, so painting the axles on a truck or van doesn't always work out. I have had good luck with Eastwood chassis products.
You might look at other years of dually Fords for different wheel spacers that may fit your needs better. I believe the 99 to 04 use 16" wheels but the brakes got bigger in 05. I don't think your 16" wheels will fit, especially if you move them in an inch.
The 99-04 trucks used the 8x170mm lug pattern with 16" wheels (not that you couldnt find larger wheels with the 170mm pattern), that said they wouldnt be a solution to the issue im facing. All the vans use the old 8x6.5" pattern.
The only real solution i see is having new front dually adapters machined with the 8x6.5 pattern.
If the 16" wheels wont clear the brake caliper then the only option is retaining the 8x200mm adapters and having rear bearing hubs machined using the 8x200mm pattern and centerbore diameter. But they would also have to relocate the lug flange on the bearing hub to accomodate the backspacing of the ford pickup wheels so the tires dont rub on the leaf springs.
I can get front dually adapters machined from forged steel for right at $500 a pair. But the rear bearing hubs would require a bit more labor and design time. Just guessing i would be into the custom rear hubs for $1000 bucks a pair.
Im not certain yet what the exact backspacing is on the Ford F-350 dually wheels because i have been unable to locate that information online. I know all the specs on my 16" Alcoa wheels, just cant find info on the 05+ 17" pickup dually wheels. I will most likely have to call a salvage yard and have them measure one for me.
Heres a rear bearing hub from a full floater axle to help visualize...
As far as the coil springs go, i have spoken with Tim at Timberline since im using his kit and we discussed springs specifically. Since its his kit and he is familiar with its characteristics i have to go with his recommendation as a starting point.
Not saying youre incorrect, but i have to have a starting point. Once its drivable again i can gauge the ride from there and make changes if needed.