Accident Where Integrity of CMC (cab mount chop) Questioned?

OK, now you’ve gone too far. Curious, do you work with Registered Professional Engineers or people that use the title engineer?

 

This arguement in a nut shell

It's about liability... it's going to cause an army of biomechanical engineers to comb over your truck and find you guilty of assasinating JFK.

Wait, whoa, hold on... it's not about liability. It's about how your vehicle modifications are going to be responsible for killing your unborn grand childeren.

The cab mout is a very important structure that is designed to withstand a side head on collision and redirect your tire under your vehicle.

The cab mount is so fragile that if you weld on it the whole entire front of your vehicle will collapse in on it's self in a fender bender.








You guys are definately engineers

 

Professional Engineers... and they are typically so stupid it hurts.

They can crunch numbers. And they can definately keep track of their billable hours.

Too bad 80% of their billable hours is spent trying to make their dumbasses understand what they say doesn't work, in real life, and trying to make them understand why. And that their cut and paste bullshit details don't even apply to the project you're working on.

 

I’m still missing your point. You said a CMC makes the structure stronger. I (sarcastically) asked why Toyota would not weld this plate or do this at the factory?

 

Hmmm, you might think I’m dumb too.

 

So you created a new thread on the same topic?

 

Because the engineers aren't considering larger tires so there is no reason to change the design. They aren't going to add an additional plate at the factory because that is an extra step, that costs more.

The part is designed to maximize efficiency on the line. The part is formed on a jig, the jig is designed to form the part to meet their spec.

The question of it makes it stronger, why don't they do it at the factory? Is dumb.

The rear portion of the frame of a 1st Gen is C channel, not boxed. Are you going to tell me that boxing the back 1/3 of the frame makes it weaker? That welding the frame degrades the material? Goes outside the design spec? Will cause liability issues?

Or are you going to say well if boxing the frame makes it stronger, why don't they do it at the factory?

 

Uhh. You and I live on different planets sir. I can’t make sense of what your saying.

The honest facts: the Tacoma cab mount doubles as a wheel intrusion barrier, by design. This helps Toyota achieve their small overlap crash performance, and it why the cab mount is the size and shape (length, width, and depth) that it is.

Likelihood: cutting it, so it is smaller, and narrower will make it weaker, and likely less effective. This is the case with most things.

Your assertion: cutting it makes it stronger (as quoted above).

I dunno. You do you.

 

I don't perscribe to one side or the other. But I truthfully appreciate the way this is laid out. Look forward to the honest rebuttal.

 

Do the choppy choppy and run 285’s cuz they look great
/thread

 

I'm enjoying the discuss and feel like there are multi good hypothesis that contradict each other. I hope my two questions listed below can positively contribute to the conversation:

From my understanding the only reason to do a CMC is to fit larger tires. The crash test video is on the stock tire size. Is it safe to assume an un-modified cab mount would interact the same way with a 33+ tire as it would with a stock tire? Meaning would a cab mount push a 33+ downwards?

The cab mount is welded to the frame. Would that mean that there is a safe welding temperature that the cab mount can withstand?

 

I’ll bet you a donut the response is in the form of an insult.

 

It's like I said in page 1. This thread has become the "which oil is better for my 3rd gen" type of thread and my final thought to conclude this, is: There is a lot of stupid showing in this thread.

Don't forget the sex dolls that over 50% of the members posting in here need or probably have in the backseat of their truck so they could drive in the carpool lane for free and use for other extracurricular purposes.

 

You could care less about people that might be injured by your actions. There is a name for people like you. And it's not "dude".

 

LOL, touche. As the only scientist in a group of engineers I'm used to y'all deluding yourselves into thinking you actually contribute something to the world other than stealing the hard work of scientists. It's adorable.

100% agree on the need for both scientists and engineers, but the best part is the shit we've given each other along the way.

 

Chacar above asked:
"The cab mount is welded to the frame. Would that mean that there is a safe welding temperature that the cab mount can withstand?"

The answer is, it depends. There are carbon steels you can weld on without adversely affecting strength and no post-weld heat treatment is required. And, there are carbon steels that are annealed (softened) to allow for welding with no ill effects but, will require post-weld heat treatment to gain the necessary strength where they would be not be welded successfully otherwise. The latter are most often high strength steels and the former are low-alloy, lower strength steels. Of course, these are still steels and still very strong.

So consider this, it is unlikely (not impossible) that Toyota is welding annealed frame components and providing a post-weld heat treatment of those frame members, and I say unlikely because I believe it would be cost prohibitive. Remember, I converted the provided "440Mpa high steel" strength claim to a very modest 64KSI strength. To me, this is nowhere near "high strength steel" as I would class high strength steel in the 80KSI range. All somewhat speculative since we don't know for a fact what they're actually doing. In fact, large manufacturers may provide their own proprietary steel ingredients (alloys) to steel mills for custom materials...who knows what they're using? In answer to your questions, my guess is there is in fact a tolerance to some welding on these frames.

FYI, I've seen questions about credentials here so, I am a certified welder with more than 25 years of industry experience, an AWS Certified Welding Inspector/Educator, and post-secondary welding instructor. I'm not a metallurgist or engineer to be clear, but like Peter Dinklage-"I drink and I know things."

 

I know this may be hard to understand... but when you take a slice of thinner metal off and you replace it with thicker metal, there is a strong possibility you just made the overall piece stronger. I know, I know, it may be a revolutionary idea.

Then you add the fact that often times a welded joint added is stronger than a piece of sheet steal that was formed around a jig.

And then you also add in the factor that you are cutting the face off the rolled cab mount and you add the piece to be welded at an angle that can actually help push the tire down/out (like it's supposed to) and offer less resistance because the piece is now flat and angled back toward the rear of the truck instead of rounded off.



And to the knuckleheads that are saying welding a piece to the cab mount can degrade the metallurgy of the cab mount because of the heat... the f'n cab mount is WELDED to the frame... and without heat, how the hell do you think the cab mount found the shape it's in to begin with?

 

I love this.

 

What I have learned so far. Any and all "mods" are a liability. Carry on!

 

While technically true, that is going to be a possibility of ANY modification you make to your truck. 33's? Steel winch bumper? Tire carrier? Sliders? Frame braces? Shock relocation?

If you get hassled by insurance, you have the most anal retentive insurance adjuster on the planet. That's just not something that a typical insurance adjuster is going to look at with that much detail. They're more interested in going after the other person's insurance if they were at fault, but I seriously doubt they're going to sit there and compare your vehicle to the engineering drawings from the manufacturer and compare part numbers.

There are countless examples of people with fully built rigs getting in accidents and getting full payouts without issue.