Hi everyone, I'm working on building a car hauler with an older COE cab. I 'm trying to decide on a 350 or 450 chassis. My plan is to have air ride so I need a coil spring front and the rear will be a semi truck s spring style. Wheelbase needs to be around 160 to 180. I'm leaning towards the 450 to get the higher GVWR and length without stretching but will if I have to. Any thoughts would be great. Thanks Ray P.S. Great site.

 

Irrelevance... Sort of.. But this is a cool picture of what I think you have in mind.

 

Yes it is but with a different cab. Also it will be lower and with smaller wheels so one can air down to load then air up to ride height and go.

 

You might want at least a 550 frame, or better yet a 650.

 

Depending on what you want to put on the back a 550 will be fine. Ive seen them done with ramps, airbags, sliding rear axle or a combo of the three

 

My only concern with going to the 550 and 650 is that they have a solid axle on the 2wds and I've never seen a way to bag them. Any thoughts? Thanks Ray

 

All superduties come with solid axles.

 

Sorry What I meant was all the solid axle 2wds I've seen are leaf springs and I've never seen one bagged. That's why I was leaning towards the 450s. I've seen some of them with the twin I beam setup. Replace the coil spring with a bag and not have to re-engineer the whole front end. Is there a way to bag a leaf spring front end? I'm looking for a better ride then a 450-550-650 leaf can give and still keep the weight capacity in range. Maybe this is not possible.Thanks for the input Ray

 

Are you talking about putting lowering bags on the front end?

 

Ridetech has 3500lbs bags for the twin i beams. This will allow for 7000lbs on the front more then what is needed to keep the 60/40 weight ratio. The truck will run at stock height/ride height down the road. When loading the entire truck will air down and then air up the front end to allow the deck to go to ground level. Once loaded pressure can be adjusted to get a proper ride. When empty the truck can ride with less pressure and still retain ride height (approx) without beating you to death. That is why the need for the rear suspension to be a truck (semi) suspension. Ridetech doesn't have heavy enough bags to carry the 60% so we go with semi bags. Their systems can be used with semi bags. The goal is to carry 4000 to 5000 on back with the truck weighing in at 7000 to 8000 empty. Hope this clears up the crazy idea I have. Maybe it will work maybe not. Thanks ray

 

From my understanding only the 4wd have a solid front axle, 2wd from 99 - 04 have twin I beam and 05 to 2012 have coils. You could fab up a 4 link with the bags in the rear and be fine. The reason i say 550 is because I've seen plenty of 550 roll backs but i don't think I've seen any 450 or 350's. LSchicago2 would know more about what your wanting to do then anyone else.

 

Thanks Pili, I've seen some PSD 450s with the solid/leaf setups but haven't looked at the 05 up yet. Are there any 550s with coils on them?
I looked at 4 linking the back but the semi system seems to be less of a headache(I'm not looking for a massive drop approx 7/9 inches). Ya I haven't seen any rollbacks under 550 either so maybe 450 will be to light.
I've seen some of LSchicago2 posts and ya your right. Hope he chimes in sometime. Still in the planning stage so any ideas are welcomed. Thanks Ray

 

My ears must've been ringing! After a little thought on this, to accomplish what the OP wants: I'd definitely go with a F550 frame. If you just want to lower the rear, it will be fine with a rear air ride from kelderman. If you want to slam the whole truck when parked, I'd use an F550 frame, (probably a 176"-186" wb, longer is better!) and weld a 2wd F350 front frame section on, using the F550 front hubs, brakes, and tires. A F350 rear frame is really not strong enough for the length & weight of this type of truck. Air rides are available for the F550's, and with a F350 2wd front you can slam it. Most of your loaded weight will be on the rear, and a F350 front end should handle this application just fine. You will be happier in the end that you went with the heavy duty F550 chassis and bigger brakes.

Not true. All 250-550 4x4's & 450-550 2wd trucks have solid axles, 2wd F250-350's have independent fronts.

BTW, if you can get an 05 or newer F550 coil spring chassis, kelderman has a front air ride available too. you just won't be able to slam it as much as the F350 2wd front end.

 

LSchicago2, Thanks for the info. I didn't know about Kelderman's air ride for the bigger trucks. Have you or anyone you know used their system?
I'm not looking to slam the truck just be able to lower it for loading and get a better ride when empty. Nice to see there are options for bagging a leaf style front end. This helps with going to the 550s. Any more ideas are welcomed. Thanks again Ray.

 

429poweredf350 has Kelderman's air ride on his DRW