Because it's next to impossible up-fit various decks and bodies with a fully boxed frame.
Even on chassis that are normally unibody, they must create an artificial open channel "frame" with flanges to bolt on utility bodies:
2017 Super Duty
- Thread starter TeamWild
- Start date
Because it's next to impossible up-fit various decks and bodies with a fully boxed frame.
Even on chassis that are normally unibody, they must create an artificial open channel "frame" with flanges to bolt on utility bodies:
toylandcruiser
Expedition Leader
Because it's next to impossible up-fit various decks and bodies with a fully boxed frame.
Even on chassis that are normally unibody, they must create an artificial open channel "frame" with flanges to bolt on utility bodies:
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Frame flex would still concern me if heavily loaded & off roaded. But thats just me. Yes, semi trucks are c channel as well but the steel & cross bar supports are wayyy stronger & wayyy thicker. In my mind, fully boxed, from front to rear, is the only way to go. My first semi truck, (in the early 80's) was 600 lb ft of torque. It is awesome to see pickups approaching the 4 digit figure !!!
Buliwyf
Viking with a Hammer
You want the frame to flex. Stiff boxed frames will just crack or tear out a weld. Semi's have a ton of flex in the chassis.
Fully boxed frames can be hydorformed. And use less steel to get the same strength. So they're cheaper to produce, that's the only real reason they exist. The rest is just hype and marketing.
Also corrosion is a concern. (Toyota) I can service both sides of a C channel frame. Can't really reach inside a hydroformed frame. If I had it my way, the new Superduty would be C channel from nose to tail, with C channel cross members.
Fully boxed frames can be hydorformed. And use less steel to get the same strength. So they're cheaper to produce, that's the only real reason they exist. The rest is just hype and marketing.
Also corrosion is a concern. (Toyota) I can service both sides of a C channel frame. Can't really reach inside a hydroformed frame. If I had it my way, the new Superduty would be C channel from nose to tail, with C channel cross members.
Can you find any examples of cracked boxed frame? (except for corroded Toyota frames)
Number one rule for chassis engineering is to design flex, damping, and compliance into the SUSPENSION, not chassis/frame. It's next to impossible to accurately predict the dynamic behavior of a flexible frame - its effective spring rate and natural frequency is always changing depending on load and what's bolted onto it.
Do you think semis do it by choice? Or simply because it's impossible to resist 36,000 lb-ft of moment (2000 lb-ft engine * 18:1 first gear ratio)? Why don't tour coaches flex? They too use "semi" engines and their axle loads are even higher (54,000 lbs on 3 axles). Perhaps their monocoque structure is way stiff in torsional rigidity?
Cheaper only in material cost. R&D, manufacturing (tooling) is much, much higher than a C-channel.
That is a valid point, hence why chassis cabs will always be made out of C-channels, for ease of bolting to the flanges.
Corrosion is always a concern, but the same applies to unibodies. But we have made large strides in anti-corrosion technology in the past 20 years.
A lot of people look at semi tractors and say: they use C-channels, and look how strong they are. But few actually look at the metallurgy in detail. Class 8s don't just slap on any random c-channel, they use what I consider extreme-tensile strength steel.
And old pickup (80s/90s) with c-channel used steel around 20,000 - 30,000 psi in strength (rebar strength). Modern HD pickups use around 35,000 psi, until the 2013 Ram HD, the first to hit 50,000 psi. This is the start of "high tensile strength". Medium duty trucks use around 70,000 psi steel, or "ultra high tensile".
A Volvo tractor? Try 120,000 psi!
So while a c-channel frame can be very strong, it's cost and weight prohibitive to do so at the pickup scale. There's a reason everyone (except Toyota) have moved to fully boxed frames on pickup trucks, and it's not "marketing", it's the most reasonable method to achieve high strength, rigidity, payload, and NVH due to less flex and low frequency resonance.
evilfij
Explorer
Rover had boxed frames from the beginning.
Anyway, I have been waiting for this as (1) I like aluminium and (2) I really want a new truck.
I wonder how much different the pricing will be from the previous generation. A reg cab f350, XL 4x4 gas seems like a good choice for a truck to me if I can keep it around $35k.
Anyway, I have been waiting for this as (1) I like aluminium and (2) I really want a new truck.
I wonder how much different the pricing will be from the previous generation. A reg cab f350, XL 4x4 gas seems like a good choice for a truck to me if I can keep it around $35k.
ssapach
Adventurer
Looks are a matter of personal opinion, but I have to say that is one of the ugliest trucks I have seen from Ford yet.
Never been a fan of Ford's looks, but they do get some things right. Haven't really heard a bad word yet about their 6.7 diesel, and they sure are nice and quiet......although I still enjoy the sound of a good old diesel rattling anyways.
Never been a fan of Ford's looks, but they do get some things right. Haven't really heard a bad word yet about their 6.7 diesel, and they sure are nice and quiet......although I still enjoy the sound of a good old diesel rattling anyways.
Buliwyf
Viking with a Hammer
Hopefully this means that F150 and Superduty seats will be interchangeable. The more "take out" new/used seat swaps available the better.
Pretty sure that semi-monocoque road coaches flex plenty. Put one wheel up on 20" of blocks and hose down the side windows, you'll see. We had to be real careful lifting those turds when I was still in school. Pitiful design like most anything in the RV industry. Give me a spring mounted body on a real frame any day.
Pretty sure that semi-monocoque road coaches flex plenty. Put one wheel up on 20" of blocks and hose down the side windows, you'll see. We had to be real careful lifting those turds when I was still in school. Pitiful design like most anything in the RV industry. Give me a spring mounted body on a real frame any day.
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plainjaneFJC
Deplorable
Anyone notice the cutaway chassis was a 450 by looking at the wheels and tires, yet it had an axle with a rear diff cover on it. So no more big Dana axles on the 450? Right at the 2:44 mark in the video above.
OCD Overland
Explorer
I don't think what was on there is the final axle. They say the axles have been beefed up, but they're not saying what to, so they're keeping it a secret for now. Pop Mechanics quoted a Ford rep on the rear axle - "It went from a Dana 80 to something stronger than a Dana 80." I don't know if that means they're going to the 110 across the board or what.
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plainjaneFJC
Deplorable
Wasn't the 450 already a 110? And the 350 was a Sterling axle?