Payload in Tacomas- Canopies and Suspension Question

[IdaSHO]

Gleaning frame strength, especially something as abstract as c-channel vs hollow tube cross sectional advantages and disadvantages, from a video showing frontal crash test results is a pretty big leap.

I totally agree. Which is why I specifically referred to resistance to failure, and not strength

I see those videos as insight to just how rigid the new boxed frames are.
And that's the problem. When they flex, they fail.

An open C is simply more resistant to failure, as it allows flex, then returns to its original form (within reason)

 

[IdaSHO]

Yep. The boxed frame thing is just the newest cool thing. Seems like most have accepted it as the truth.

I just hope that Ford did their homework, and didnt just fall on their own sword with the latest chassis change.

 

[Dalko43]

Corrosion and boxed frames isnt limited to Taco's

Many MFG that have run boxes frames fights the debris stuck in the frame problem.

If there is a hole in the frame.... SOMETHING is going to find its way in there. And there are always low spots. :sombrero:
Add a bit of moisture, and it starts.

Corrosion is an issue with any frame, regardless of its construction. The frames on 4runners and LC's have been proven to be long-lasting despite being boxed, as long as you use the proper upkeep and cleaning techniques. The c-channel frames, at least those used on the newer Tacoma's and Tundra's don't seem to have any advantage in that regards.

And obviously a boxed frame that is stronger than a open c-channel will be, uh, stronger.

But for a given strength, a frame that has a bit of give will be more resistant to failure.


There are a few crash/safety vids floating around on the internet that do a decent job of showing the difference.

Here is one of them...

https://www.youtube.com/watch?v=aYbXeyzwsmY

That video is simply one man's opinion. And if you check out his other videos, he spends a lot of his time defending Ford's c-channel frame and criticizing Ram's and GM's boxed frames, without much evidence behind his argument. Also, I'll point out that the new Ford Super Duty did finally switch to a fully boxed frame...so obviously even the engineers at Ford agree that such a setup is better suited to pickup trucks.

Any frame is going to have a failure point. Any frame is going to flex some. People make the argument that c-channels frames help to avoid failure by allowing for more flex and give...and yet I don't hear about many LandCruiser or Jeep frames failing because they were overly rigid. I'm sure there are examples out there of idiots overloading their vehicles, but my point is if you stay within the manufacturers recommended capacities, you're highly unlikely to have any issues with a boxed frame breaking.

 

[DaveInDenver]

Two points to add to your comment Dalko43.

It's probably farting in church to mention that both the Cruiser and 4Runner are still built in Japan. There wasn't a particularly big thing about old Toyota truck frames rusting out but Tacoma being designed and built in N. America seems coincidental.

Second, the boxed vs C-channel argument does in fact boil down to capacity. I actually prefer having the open channel for the ability to clean and repaint.

 

[Dalko43]

It's probably farting in church to mention that both the Cruiser and 4Runner are still built in Japan. There wasn't a particularly big thing about old Toyota truck frames rusting out but Tacoma being designed and built in N. America seems coincidental.

Coincidental as in the origins of the Tacoma's build had nothing to do with its rust problems? I honestly don't think frame construction has much to do with whether or not a vehicle will rust out prematurely. I think the quality of finish and paint at the factory is more relevant to such issues. The earlier Tacoma's seemed to have a greater # of rust issues relative to Toyota's other BOF offerings.

Second, the boxed vs C-channel argument does in fact boil down to capacity. I actually prefer having the open channel for the ability to clean and repaint.

I agree; c-channel vs boxed frame plays a great role in determining capacity. A lot of well-regarded global 4x4 platforms (jeep, defender, LandCruiser) have been using that boxed frame construction for a while now. I think most of the domestic companies' trucks switched to that setup at least 10 years ago. Ford's Super Duty, was the last holdout to join their ranks. It's not a "fad" or "new trend" as some people suggested earlier, but just the way things are.

And yeah I can see some advantages to cleaning out a c-channel vs a boxed frame. But with the right tools you can still do a pretty good job of cleaning and refurbishing a boxed frame, especially those with drainage or accessory bolt holes.

 

[IdaSHO]

Corrosion is an issue with any frame, regardless of its construction. .

Significantly worse in boxed, for the obvious reasons. Even you have admitted that.

Open C is always easier to clean. Box frame simply isnt easy to clean, and will ALWAYS be more problematic to clean.

Those trouble to clean spots are the spots that lead to rust.

Simple fact really.

That video is simply one man's opinion.

Yep, as is yours, and mine, but for you to think your posts hold more water than his, or even mine, is hysterical really.

Any frame is going to have a failure point. Any frame is going to flex some. People make the argument that c-channels frames help to avoid failure by allowing for more flex and give...and yet I don't hear about many LandCruiser or Jeep frames failing because they were overly rigid.

You need to get out more.

Frame cracks and failures for FJs are common now.

As is frame failure due to rust/rot for many Jeeps ( points at my comment about corrosion )

 

[DaveInDenver]

Coincidental as in the origins of the Tacoma's build had nothing to do with its rust problems? I honestly don't think frame construction has much to do with whether or not a vehicle will rust out prematurely. I think the quality of finish and paint at the factory is more relevant to such issues. The earlier Tacoma's seemed to have a greater # of rust issues relative to Toyota's other BOF offerings.

Yes, tongue-in-cheek coincidental because I believe the reason the Tacoma (and Tundra for that matter) exist as a way to make a bare minimum in materials, design, quality truck to meet the 6,000 lbs GVWR in their class and the expectation that the truck is driven mostly empty on Interstate. Some may be tariffs but simply manufacturing the Hilux domestically would have solved that. For all my huffing and puffing, it's not really a boxed frame I want but specifically the Hilux frame. Let's also be clear, Toyota as a company knows how to design frames from light duty up to heavy duty commercial, being that they also own Hino. I assume their large trucks do use C-channel since that is common. One complaint about the boxed frames on 1 tons and what not is it's a PITA to mount 5th wheels and commercial bodies on a boxed frame.

 

[Theoretician]

I totally agree. Which is why I specifically referred to resistance to failure, and not strength
...
An open C is simply more resistant to failure, as it allows flex, then returns to its original form (within reason)

You can dive into semantics all you like. Hollow sections tend to have more of sudden failure than c-channels, sure. For a given cross sectional weight, and all else equal within the realm of a truck frame, failure of any sort will tend to occur later with a hollow section than with a c-channel. So yeah, a c-channel will bend itself out of spec earlier but still hold load when a hollow section is still within the elastic range of deformation, and then both sections will be unuseable once the hollow section has buckled.

Hollow sections are simply more structurally efficient - the biggest weakness of c-channels is lateral buckling between braces because of the asymmetry of the section. The biggest benefit of c-channels is ease of use, which carries the ease of maintenance benefit. The maintenance side alone may justify usage over hollow sections until frames start being made of aluminum, but from a strength perspective you need a lot more mass to make a c-channel that will fail as the same load as a hollow section.

 

[DaveInDenver]

Hollow sections are simply more structurally efficient

The ability to use less material (cheaper, lighter, etc) to meet a goal is the benefit to manufacturers but I wonder if hydroforming has had something to do with the proliferation of boxed frames. No welding, fast manufacturing, etc. The older Toyota frames like on my '91 were two stamped 'C's profiles welded along the seams on top and bottom, so there was some intentional decisions as that would seem to be a relatively labor intensive process. Now it's being marketed as better but it's really that it benefits the manufacturer.

 

[Adventurous]

Thoughts on the windowed frame boxing kits? That would provide some space for water to escape or to clean/paint the inside of the frame while still providing some of the benefit of being boxed. It's a compromise solution for sure, but better than nothing. Can't find an actual picture of some welded in so this will have to suffice.

That said, this stuff seems to be well reviewed and would give peace of mind to the frame insides: http://www.eastwood.com/internal-frame-coating-aerosol-black-14oz.html

I think I'll blast the boxed portions of mine with that after spraying it out well.

 

[DaveInDenver]

I sprayed the inside of my boxed section with the green version of that Eastwood stuff.

http://www.eastwood.com/eastwood-internal-frame-coating-14oz-aerosol.html

I don't know how it will last and honestly it's tough for me to really think it will last because my truck was 7 years old when I got it and I could only clean out so much much debris. But I did two coats and what I can see seems to still be there.

The first thing I did to my truck was clean the frame, wire wheel whatever looked bad and painted the whole thing. I also do a Fluid Film on my whole frame twice a year.

 

[IdaSHO]

Thoughts on the windowed frame boxing kits? That would provide some space for water to escape or to clean/paint the inside of the frame while still providing some of the benefit of being boxed. It's a compromise solution for sure, but better than nothing. Can't find an actual picture of some welded in so this will have to suffice.

That said, this stuff seems to be well reviewed and would give peace of mind to the frame insides: http://www.eastwood.com/internal-frame-coating-aerosol-black-14oz.html

I think I'll blast the boxed portions of mine with that after spraying it out well.

That's about the only way to do it.

Factory boxed frames are pretty well doomed from the factory, with regards to drain holes and the ability to keep clean, and ultimately avoid rust problems.

The top and bottom surfaces of the boxed frames is where most of the strength is, and this is right where the drain holes need to be.


For the guys that cannot seem to understand the problem with boxed frames, and the (in)ability to keep them clean and rust free, this video should help...

https://www.youtube.com/watch?v=htACINMZFi0

And even with proper drain holes, it is simply a matter of time until the drain holes are plugged by debris of some sort.

Most of the time the debris turns out to be rust scale that has formed inside the chassis and broken off.

And once those holes are obstructed, things go from bad to worse very fast.

 

[IdaSHO]

I don't know how it will last and honestly it's tough for me to really think it will last because my truck was 7 years old when I got it and I could only clean out so much much debris.

Its a tough battle, for sure.

Ive got a '99 TJ that is known for rear frame corrosion due to the "simple" problems Ive mentioned with box frames.

At the end of the day, there is only so much you can do.


All the while, I've got a 20+ year old Ford truck parked on the curb, that has NEVER seen a garage, never been washed, and has lived its entire life in North Idaho, with zero frame issues.

A box frame might look "superior" on paper, but I don't see it. And until a box frame is 100% sealed from the elements, Ill stick to open C.

 

[dman93]

No offense, but almost every posting here talking about deformation, strength etc is completely ignorant of the basics of an engineering discipline known as "strength of materials". As I wrote in an earlier posting, there are two completely separate structural properties of a frame, stiffness and strength (not getting into corrosion resistance etc).

Stiffness is the resistance to deflection, either bending or twisting or some combination of both. That deflection is not permanent, remove the load, and the frame returns to its neutral state. Too much deflection can cause a poor ride (the frame essentiallly becomes another spring that's not wel-damped and may bounce at a different frequency than the suspension, causing ride and handling problems), the bed hitting the cab, etc. Strength is the resistance to failure. That failure can be permanent deformation of the frame, or actual breakage cracks etc. A frame that is too stiff is almost never bad, adding stiffness and/or strength can add cost, weight, or corrosion problems due to poor internal drainage. I am a mechanical engineer and used to design frames for over-the-road heavy-duty trucks. When we had frame failures or poor ride caused by flexible frames, adding stiffness ALWAYS helped. Making a C channel frame stiffer in bending involves making it thicker or taller, both of which create cost and packaging (space) issues. Boxing it helps both bending stiffness and torsional (twisting) stiffness, but also adds cost, weight, corrosion risk as well as making it hard to attach crossmembers or suspension brackets. Some structures can indeed be too stiff, but that's rarely the case with frames. Trust me, it gets even more complicated, but it's useful for people who have interest in structures to understand the difference between stiffness and strength, and how a combination of design and materials affects those properties. Sorry, I'll get off the soapbox now

 

[Dalko43]

Significantly worse in boxed, for the obvious reasons. Even you have admitted that.

Open C is always easier to clean. Box frame simply isnt easy to clean, and will ALWAYS be more problematic to clean.

Those trouble to clean spots are the spots that lead to rust.

Simple fact really.

Well so much for putting me on the ignore list. I agree a C-channel is easier to clean than a boxed frame.

But claiming that rust is much worse on a boxed frame vs a c-channel is not simple fact. Most people don't clean their frames at all, regardless of whether they're c-channel or boxed. I've seen boxed frames last just as long as c-channel ones...anecdotal on my part for sure...but since you're the one claiming to have a fact on your side, why don't you give me some actual statistics for how long a boxed 4runner frame lasts versus how long a Tacoma c-channel one lasts? I'm willing to bet that your own experience on the issue is anecdotal as well.

Yep, as is yours, and mine, but for you to think your posts hold more water than his, or even mine, is hysterical really.

Yes, but my opinion has confirmation of sorts in that Ford now uses a fully boxed frame for the Super Duty, as do most other pickup's and BOF SUV's...I suppose there must be some reason why that frame type is so prevalent within the 4x4 vehicle segment.

Frame cracks and failures for FJs are common now.

How common is "common?" Are you basing this off a few internet threads or do you actually have some NHTSA TSB's and recalls to prove your point? Were these vehicles stock or over GVWR? Again, my anecdotal side here, but I've seen plenty of 10 year old FJ's, both stock and modified, on the road and I haven't seen any common issues with that frame failure.

As is frame failure due to rust/rot for many Jeeps ( points at my comment about corrosion )

Again, how common is "common?" FWIW, Toyota was a company that was noted for having frame rot issues, and all of those affected vehicles (Tacoma, Tundra, Sequoia) had C-channel frames: https://www.autoblog.com/2016/11/14/toyota-3-billion-settlement-rusty-truck-frames/

That seems to stand in direct contradiction to your conventional wisdom on the merits of c-channel frame construction. In my opinion, the quality of construction and finish at the factory has more to do with premature rust issues than does the type of frame used.