Is there a reason modern trucks don't come with fully sealed frames to prevent rust?

Honda Ridgeline aka the gold standard of pickups

 

Full size domestic truck frames do not rust as fast as a Tacoma frame.

Every fullsize domestic 1ton frame I have ever seen has looked better than the frame on my Tacoma. Those trucks have also seen more miles on treated roads than my Tacoma. None of these frames have been treated.

 

This, I've been saying this for decades.

 

These tacoma frames appear paper thin opposed to my old tundra, and even that frame was noted for rust issues. When i saw a buddies 2019 taco frame, i knew i needed to do something real soon once i bought mine. Best rust proofing time imo, is when all the black frame paint is all there nice and shiny.

 

Dump trucks, big rigs, and unimogs have open c-channel frames, just like our Tacomas, because they are better by every single metric.

Unimog frame:

 

Good chance the next “Tacoma” will be uni-body.

 

I can think of a few reasons why Toyota would steer clear of galvanizing the frames.

1 - if they went the hot dipped galv route, I think they would have to seriously consider modifying their design to account for heat warping during the dipping process. Some of those frame sections are pretty thin and would warp all over the place after being dipped. Plus the liquid zinc would plug up/fuck up all of your threaded bolt holes. (I used to work for a steel fabricator and seriously explored this option haha)

2 - I’m willing to bet Toyota legal has something to say about fixing the problem now. Maybe fixing the issue would open a Pandora’s box of liability claims related to frame rust. Can’t deny responsibility for the frame problems anymore if they go and fix the issue lol.

3 - I’m guessing the total cost of frame rust claims each year is less that the projected cost of fixing the problem. My money is on this one, unfortunately.

 

Man, I’m digging the pipe cross bracing. No need to brace the flanges.

 

The internet is strong in here

 

Profit. They sell every truck they make without taking on this cost today. They don't need to add a dime of cost to the frame to still sell them all. We, the consumer, won't pay them extra for sealing the frame. Tech inside, we pay for. More HP, we will pay for. Bigger tires, we will pay for.

 

I don't understand why they stopped doing that. My coworker has a mid 1990's Chevrolet 3500 that has lived its entire life in the rust belt. There is not a lick of rust on the body panels despite much paint missing from years of abuse. My understanding is cost wasn't an issue.

 

#1 didn't seem to be a problem for when they would do it to body panels which are much thinner than the frame materials.

 

The Unimog is awesome, but it's 50% tractor.

It's frame is not better in every single metric, its better for hauling big loads off road at low speeds offroad. That's the only situation where a flexy frame is good.

We're talking about a Tacoma here, its 0% tractor.
A rigid frame is better in ride quality, handling and composure. The next Tundra and Tacoma will be fully boxed, because it is absolutely necessary to increase load capacity, modernize it's ride and composure, and keep it light.

Let the suspension do the flexing

I don't knock C-channel frames, if they're done right. For instance, the 92-93 Dodge Cummins frames are 8" tall, 1/4" thick, and beastly BUT heavy, no one cares on a Diesel work truck.

 

There are things we are forgetting to mention here.

Each frame type will react differently in a collision. If you look almost all new trucks will have a boxed front and c channel out back. It has some to do with the weight the frame will be carrying and some to do with crash handling. The frame can also have different metal thickness and strengths. A frame may have a HSS (high strength steel) or Taylor rolled for different thickness metal at certain points. This helps deflect or absorb crash energy.

There is a lot that goes into that ladder we sit on

 

In my limited Toyota experience, I'd say this is highly debatable in a lot of cases. Definitely with the older Toyotas, but not so much with the newer ones (even my 2017 which had the recall campaign expanded to it). Hell, I'm currently looking at my coworker's Chevrolet 2500 Duramax which is right around the same year as my Tacoma. The Chevrolet appears to have more surface rust starting on the frame than my Tacoma. I traded in my 2008 Canyon in part because I didn't like how the frame was starting to look.

 

My understanding is that the only two trucks that currently incorporate a C-channel frame are the Tacoma and Tundra. The F150, Silverado/Sierra, and RAM are all fully boxed front to back.

 

The frame is better in every single metric. No question. Open C-channel isn’t a just a technology, it’s a lifestyle.

 

Imagine a sealed frame crossing a water crossing? You don't want any buoyancy.

 

Increased body roll caused by a frame that's too rigid??? Umm, physics says no. Older vehicles had much wimpier sway bars, were softer sprung, and heavier...that's where the increased body roll on those vehicles came from.

Ah wait, YouTube said it was so. Nevermind.

 

I’m thinking they use a much less “intense” galvanizing process for thin material like that. HDG is used for structural steel 1/8” thick min, as a rule of thumb.

I’m talking hot dipped galv where you dip the steel in a pickling tank and then drop it into tank full of molten zinc for about 5mins. I can assure you thin material warps in those conditions.