Why the thinner frame steel?

I was looking at used full sized trucks (F150, Chev 1500). Something with a

8 foot bed. I was surprized that they use the same ~1/8" thick steel U channel frame that is used in the S10/Ranger. I was expecting something beefier in a full size. Why do this?

I see they use a boxed frame in the newer trucks but it is not as tall. For a deeper bed I'd guess.

Reply to
JohnR66
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I commend you for looking under the hood and noticing. They are all using thinnner metal to cut costs and weight a bit and they use a stronger grade of metal to try to make up for less metal cross-sectional area. The proble with this while it looks good on paper for advertisements (like boxed frame) it alos causes a few problems of its own. First the thinner metal is more weakend by rust than older metal because 40 or 50 thousandths from 1/8 inch is a bigger deal than same from 3/16 inch thick metal. (also with fame inclosed it cannot wash out well and can be more prone to rust inside weakening it unseen) Second, box frames are not forgiving when they exceed their load limit and can buckle suddenly without warning while the classic old C channel is very forgivening in this regard. (this is the reason when you still see C channel on very serious dump trucks and semi's)

----------------- TheSnoMan.com

Reply to
SnoMan

You bought up good points about the box frame. I notice that they paint them (for good reason).

Saving weight on the vehicle's very foundation seems dumb to me. Take a 18 foot long piece a steel that is 12" wide (unfolded C channel) and 1/8" thick)

216" x 12" x 1/8" x .27 = 87.48 punds (.27 is the density of steel pounds/cu in). Adding an extra 1/32" increases strength quite a bit yet adds only about 21 pounds or 42" total for both frame rails. John
Reply to
JohnR66

That's true, and steel is very very cheap. 42 pounds of steel would only cost a few dollars. Too bad. I would bet they're not worried about the cost, but they are worried about shaving weight.

Reply to
Joe

I think they are worried about both. Every new design or change seems to also focus on it being cheaper to make too be it from less labor, less materials or both.

----------------- TheSnoMan.com

Reply to
SnoMan

Using on-line prices and weights, I found this info for boxed steel (not C channel):

4x2x.120x216= $111.78 85.5 pounds. 4x2x.188x216= $186.30 123.7 pounds.

The extra $75 would probably be somewhat of a concern for thousands of vehicles (granted, the bulk prices would probably be considerably less), and the extra pounds might cut a half mile per gallon from their CAFE ratings, so I would think that the manufacturers would be concerned with both the price and the weight somewhat equally. Gotta do what you can to save money and increase gas mileage or they'll get some other fool to be their CEO. Never mind that the vehicle bodies won't last near as long as they used to. The sooner they break, the sooner the sucker. . .er. . . customer will buy another one.

SC Tom

Reply to
SC Tom

At a family get together this weekend a couple construction guys were commenting on the new Chevy and Ford long box trucks. A guy had one at a shop and they used a bumper jack to pick it up. Bent the frame on the unloaded truck just picking it up by the rear bumper.

Reply to
Mike H

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