Payload in Tacomas- Canopies and Suspension Question

DaveInDenver

Middle Income Semi-Redneck
Ohhh....as p nut has been telling me, it ain't that much bigger...
It's a foot bigger in a game where inches count!

Super Cab 6.5' bed 5.0 V8....2200lbs payload, 395hp, 400 ft/lbs tq...darn near the same gas mileage...if you look, and all not that hard, can be had cheaper than a Tacoma. Real tempting...
You need to just poo or get off the toilet, man. An F150 makes sense but having a Ford in the 1990s is what made me a Toyota owner. I'm sure they're better now and certainly Toyotas aren't as good as they used to be. But habits and stereotypes.
 

Dalko43

Explorer
I think the relevant comparison is the Tacoma vs. Hilux, not a general discussion. They are close cousins of similar size and weight. I don't know one way or the other that the wall thickness is the exactly same. The material on my 2008 is approximately 0.120" thick. The open section is the same wall thickness but is partially double wall. I assume the Hilux frame is probably something similar like 3mm. It would interesting to know this for sure, though.

Assuming it's made of a similar wall thickness a boxed frame will be more rigid. In fact Mike Sweers has said specifically that the Tacoma frame was modified to be more "compliant". What that means is obviously softer riding.

http://www.automobilemag.com/news/q-a-with-2016-toyota-tacoma-chief-engineer-mike-sweers/



Either way, an open channel would need to be thicker to resist distortion and fatigue at the same force as a boxed profile for a given wall thickness. Bucking does actually happen to Tacomas, which is solved on first gen with those frame plates and all gens sometimes get boxed. You can tell an overloaded Taco from the wrinkle in the section over the rear axle.

View attachment 414687

I'm not saying the C-channel isn't a totally viable option, it obviously is. It can be strong enough but the Tacoma has a 5,850 lbs GVWR and my opinion is it's not designed with the same expectation to go beyond that as the Hilux and the frame is fundamental element to that.

I've heard a similar argument from others at Toyota, but I think the idea that the frame on a Tacoma is meant to be more compliant (aka flexy) is marketing fluff.

If you want a complaint ride, you retune the suspension, not the frame. Like I said, Toyota's flagship 4x4's are fully boxed and I've never heard anyone complain about those vehicles riding too stiff because of their frames.

As you noted, there is a payload discrepancy between the hilux and the Tacoma; im inclined to believe that frame construction has something to do with that.



Sent from my iPhone using Tapatalk
 

DaveInDenver

Middle Income Semi-Redneck
I've heard a similar argument from others at Toyota, but I think the idea that the frame on a Tacoma is meant to be more compliant (aka flexy) is marketing fluff.
I quoted Mike Sweers (Toyota North American's Chief Engineer for the Tundra and Tacoma), who said "We have no qualms saying that the Hilux and Tacoma are brothers as far as the platform. The basic frame design is similar. We [the Tacoma] have a little bit more compliancy in our frame compared to a Hilux. That's mainly to satisfy the ride requirements for the North American customer."

What that means is up for interpretation I guess, but the implication to me is to soften the ride for people who drive a truck that they want to feel like a car.

I'm in complete agreement with you. You want the chassis as stiff as possible since it's more effective to tune suspension. That's a fundamental design criteria for race cars. But as I noted, some platforms do flex a ton. Now no one is going to cite a Unimog for it's road handling prowess, so a twisty frame like that makes probably makes perfect sense for very refined tractor.

All I can tell you is when I put my rear springs on I put my jack stands under the frame right in front of the place where it turns up ahead of the rear axle, close to the gap between the cab and bed. When I let the jack down (which was under the rear third member) my rear end sagged so much that I didn't feel comfortable letting it cantilever without a 3rd jackstand under the receiver hitch to help support it. This is something (letting the back end hang in space) I did with my '91 and I don't ever remember there being that much flex in it. It was probably only a couple of inches but the frames on the 2nd gen seem very flexible.
 
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Dalko43

Explorer
I quoted Mike Sweers (Toyota North American's Chief Engineer for the Tundra and Tacoma), who said "We have no qualms saying that the Hilux and Tacoma are brothers as far as the platform. The basic frame design is similar. We [the Tacoma] have a little bit more compliancy in our frame compared to a Hilux. That’s mainly to satisfy the ride requirements for the North American customer."

What that means is up for interpretation I guess, but the implication to me is to soften the ride for people who drive a truck that they want to feel like a car.

I'm in complete agreement with you. You want the chassis as stiff as possible since it's more effective to tune suspension. That's a fundamental design criteria for race cars. But as I noted, some platforms do flex a ton. Now no one is going to cite a Unimog for it's road handling prowess, so a twisty frame like that makes probably makes perfect sense for very refined tractor.

All I can tell you is when I put my rear springs on I put my jack stands under the frame right in front of the place where it turns up ahead of the rear axle, close to the gap between the cab and bed. When I let the jack down (which was under the rear third member) my rear end sagged so much that I didn't feel comfortable letting it cantilever without a 3rd jackstand under the receiver hitch to help support it. This is something (letting the back end hang in space) I did with my '91 and I don't ever remember there being that much flex in it. It was probably only a couple of inches but the frames on the 2nd gen seem very flexible.

I think you and I are on the same page. The "compliant ride" argument is Toyota's official explanation for why the Tacoma, and Tundra, have c-channel frames...but I have a strong suspicion that cost has more to do with that design decision than does ride comfort.

And I totally agree that there are some 4x4 platforms that are specifically designed to have chassis and frame flex, the unimog being the more prominent example of that...you spend just a little bit of time reading up on the engineering behind that vehicle and it's apparent that it's in a totally different league from the Tacoma. All frames flex, some more than others. But unless you have something like a unimog that was built from the ground up to accommodate a flexing chassis, you generally want your frame to remain as stiff as possible so that the suspension can be tuned for flexing and articulation.

All that said, I've driven more than a few 2nd gen Tacoma's, and I never once thought that the whole platform was going to break or fall apart because of it's c-channel frame....I still regard it as a solid vehicle that can take crap-tons of abuse, which I suppose is a testament to Toyota's general quality. The Hilux is simply a bit tougher, and I think the heavy duty frame has something to do with that.
 

Clutch

<---Pass
It's a foot bigger in a game where inches count!

I know! Try to keep telling p nut that!


You need to just poo or get off the toilet, man. An F150 makes sense but having a Ford in the 1990s is what made me a Toyota owner. I'm sure they're better now and certainly Toyotas aren't as good as they used to be. But habits and stereotypes.


One more year, one more year... when I cash in some assets. (Until then! :p)

Should be even by now! Yan know, Toyotas haven't changed all that much over the years, are they aren't as good, or just seem that way?
 
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dman93

Adventurer
There are so many variables that affect stiffness, i.e. resistance to bending or twisting; and strength, i.e. resistance to permanent deformation or failure, that one can't really generalize about c-channel vs boxed without knowing all the frame dimensions ... and material properties. One "problem" with the double-cab 5' bed and a shell, is that the CG is further back relative to the rear axle with the short bed. I have definitely noticed this carrying heavy loads in my DCSB. With a 6' bed you can move a given load a foot further forward, although obviously a 6' camper is heavier than a 5' camper.
 

IdaSHO

IDACAMPER
resistance to permanent deformation or failure

That's my biggest hangup with fully boxed. A close second is corrosion.

Open C is pretty "stupid proof" as it allows a great deal of flex without permanent damage.

Not so in a fully boxed chassis. Fully boxed is designed for rigidity. Push it beyond its limit, and it doesn't just flex, it deforms and fails.


Like a lot of things, a little give goes a LONG way.
 

DaveInDenver

Middle Income Semi-Redneck
That's my biggest hangup with fully boxed. A close second is corrosion.
I believe corrosion is a big reason for the way the frame are designed. Tacoma frame rust is currently even part of a class action lawsuit. Building up debris inside the frames has always been a problem with Toyota trucks, even the venerable 79-95 would rust and fail at the up bend in front of axles. The 1st gen Tacoma was still boxed there and opened above the axles. That was probably just a cost reduction effort. The 2nd gen frame I think was engineered more and reducing places for corrosion from packed mud probably was on their minds.

Not so in a fully boxed chassis. Fully boxed is designed for rigidity. Push it beyond its limit, and it doesn't just flex, it deforms and fails.
Everything will eventually fail. There's evidence that Tacoma frames exhibit buckling and, sure, that's better than a collapsed rail. But I suspect that the force required to deform a Hilux rail is going to be whole lot more than being a couple hundred lbs over GVWR. But I also admit I have no idea how much margin either design has in it. I do honestly wish I knew if the 2nd gen frame did have more than the 1st gen, since I really don't want to reinforce or box it in if I don't have to.
 
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IdaSHO

IDACAMPER
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.


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
 

(none)

Adventurer
I have a hard time believing they moved to an open channel frame just due to corrosion. That seems very odd when many other (even Toyotas) have been fully boxed for decades without the corrosion issues (such as 4runners and land cruisers).
 

Theoretician

Adventurer
Interesting video, but wouldn't the gap between the cab and the bed be heavily influenced by the cab mounts and have little to do with the frame strength? Most cabs that I've seen are isolated from chassis vibration via rubber or polyurethane that would be stressed in shear in an accident and body mounts made of steel that would be stressed in bending in a frontal accident. Both shear and bending are deflection modes that are at least an order of magnitude softer than the axial deformation that the frame would see in such a loading.

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.
 

toylandcruiser

Expedition Leader
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.


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

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

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