2017 Super Duty

toylandcruiser

Expedition Leader
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.

Don't even try. They drank the kool aid and there is I turning back for them.
 

OCD Overland

Explorer
Wasn't the 450 already a 110? And the 350 was a Sterling axle?
Don't know about the 350, but they did switch the 450 to the 110. I assume that the pop mechanics quote was for the 250, so if they upgrade the others or not is a guess. I can't see them downgrading them though.
 

Buliwyf

Viking with a Hammer
Old F250/F350's had Super Dana 60 front, Sterling/Visteon 10.5" rear. The Dually's had Dana 80's IIRC. No idea on the 450/550, but you ain't breaking it.
 

RoyJ

Adventurer
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.

Just so we're talking about the same thing - when I say motor coach, I'm referring to REAL coaches like MCI, Prevost, Volvo, Setra, Van Hool, and old Eagles, not RV coaches like Dutchman, Thor, etc.

Other than a few million $ RVs built to real coach standards (Newells), these two are vastly different.

Motor coaches and city buses are some of the toughest chassis you can have. They're full monocoque, not semi. In fact, older GMs had stresses skins as well.

BP20130802x14y05104.jpg


As a Prevost owner myself, I can tell you yes, 20" block no problem. In fact, I worry about snapping my sway bar before hurting the chassis.

When agencies cheap out and use body on frame school buses in revenue services, that's when problems occur. They can't stand up to the rigors of over the road line / transit service. Not to say they aren't built well, just not up to coach standards.
 

RoyJ

Adventurer
Not true. The 40 series is not fully boxed, the 60 series is not boxed front to rear. 80 series is the first to be fully boxed.

Fair enough, the FJ40/60 is open past the rear axle, but those regions don't affect rigidity.

But do you really feel Toyota boxed the middle section, and the entire length 80 series on-wards, strictly for marketing?
 

toylandcruiser

Expedition Leader
Fair enough, the FJ40/60 is open past the rear axle, but those regions don't affect rigidity.

But do you really feel Toyota boxed the middle section, and the entire length 80 series on-wards, strictly for marketing?

Are you implying that an 80s hilux has a stronger frame than a 2015 super duty? You understand that stiffer isn't stronger right?
 

RoyJ

Adventurer
Are you implying that an 80s hilux has a stronger frame than a 2015 super duty?

No, why did you feel that way?

What I am implying, is that the Hilux frame has a greater section modulus per unit weight than a 2015 SD. Once we know the yield strength of its steel, we can also conclude if it's stronger (per unit weight)

You understand that stiffer isn't stronger right?

Of course, and you would know that if you actually read my earlier post.

Do you understand that a "strong" frame is not an ideal design spec? I can build you a frame with high ultimate strength, that would twist your camper to pieces under articulation.

Also, if you looked up the yield strength of the frames, you would know the 2015 SD is the most flexible, AND the weakest per weight:

Dodge: 50,000 psi
GM (post 2011): 60,000 psi
Ford: 36,000 psi
 

toylandcruiser

Expedition Leader
No, why did you feel that way?

What I am implying, is that the Hilux frame has a greater section modulus per unit weight than a 2015 SD. Once we know the yield strength of its steel, we can also conclude if it's stronger (per unit weight)



Of course, and you would know that if you actually read my earlier post.

Do you understand that a "strong" frame is not an ideal design spec? I can build you a frame with high ultimate strength, that would twist your camper to pieces under articulation.

Also, if you looked up the yield strength of the frames, you would know the 2015 SD is the most flexible, AND the weakest per weight:

Dodge: 50,000 psi
GM (post 2011): 60,000 psi
Ford: 36,000 psi

Soooo you're in agreement then. A stiff boxed frame is not stronger than a flexy one. Sweet.
 

Buliwyf

Viking with a Hammer
Fair enough, the FJ40/60 is open past the rear axle, but those regions don't affect rigidity.

But do you really feel Toyota boxed the middle section, and the entire length 80 series on-wards, strictly for marketing?

No no no. You got that backwards. Strictly for cost and ease of production. It's just another engineered means to an end.

It's silly when it's marketed, LATER, as high performance chassis nonsense. Snake oil. It ain't anything fancy, it's just a hydroformed tube frame. Whoop de do. I'll take C channel over it ever day. I guess that's what sales guys do, though. Take a cheap production method, and spin it as some kind of whiz bang new idea that's going to cure all of our ills.
 

Buliwyf

Viking with a Hammer
That was never in question.

What was in question is the current SD being flexy AND weak.

Have two of them to myself. 2008 and 2015. The one for work is on dirt, railroad, and pipeline roads all the time. Absolutely not weak. A little flex, just enough. Not really significant, the rubber body mounts soak it all up. I rate it higher than our Dodges and GM's. Just don't open the rear suicide doors when you're all flexed out, if you made the mistake of getting the X cab instead of the CC.

Section modulus?
PSI yield rating?

All BS out in the field. I'm either welding the spring hangers back onto a cracked weld, or I'm not. So far the Superduties have handled the most abuse for us. Followed by Dodge, then the GM 2500's, then the GM Vans, then the POS Ford vans. But frames are the least of our worries.

To call a Superduty frame weak, is a perfect Red Flag that someone doesn't have experience with the truck in the field. That frame is anything but weak. Especially if we're using little SUV's as examples. A Hilux? Yeah right. Toyota's are not the bullet proof rigs we hoped they were, even when used within their rating, we ate them up quick.
 
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plainjaneFJC

Deplorable
Have two of them to myself. 2008 and 2015. The one for work is on dirt, railroad, and pipeline roads all the time. Absolutely not weak. A little flex, just enough. Not really significant, the rubber body mounts soak it all up. I rate it higher than our Dodges and GM's. Just don't open the rear suicide doors when you're all flexed out, if you made the mistake of getting the X cab instead of the CC.

There is some merits to both sides of this, but you cant see it thru your blue tinted glasses.
 

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