Please don't let this start a flame war. I was at the Washington D.C. autoshow today. After seeing everything in there I could find no vehicle under 40k, or over really, that I would rather have or fits my needs better than my 04 Screw FX4. Which I love. After seeing all the negative posts about the Titan I thought I would check it out myself. When I got to the Nissan, they had a titan frame and running gear on display. I was amazed to see it was a fully boxed frame. I did not get a feel for the thickness though. I know that the Tundra uses a really week frame and depends on the body for the rest of it structual integrity, or lack there of. I traded in my 97 Tahoe, which had nothing but problems, to get my FX4. Even with all the problems I still loved that truck but it had a C channel style frame on it. I don't know about other American manufacturers such as Dodge or Chevy. But with the F-150 and the Titan having fully boxed frames, if they don't have them they sure need to get them.
Adam

Praying for no flame war.

 

Seems like all the manufacturers are pitching boxed frames now. I'd love to have a truly knowledgeable engineer explain the pro's and con's of boxed frames versus the C channel type. I understand the basic physics that the box structure will be stronger given the same section width, material type, and thickness, etc.

But if you look at 18 wheelers, or medium duty box trucks, they all have C channel frames. Heck, even the SD trucks have C channel frames, and my guess is they are still much stiffer than the new F150 frame.

Does it just boil down to cost, marketing hot air, or what? Any engineers out there that can shed some light on this?

 

Ford, Dodge and Nissan used boxed Frames, Chevy and Toyota do not.

Pictures of Frames

 

XCR440SP, thanks for the pics they were very helpful in explaining
to Chevy driving friend. I dont think that will make a big difference to him when he goes to purchase his new truck, but sometimes you just can't help people.

 

Agreed! Thanks for those pics there more informative than anything at the autoshow. I would love to see the Titan frame on that same machine.

 

i'm with fx4triton

 

dbossman...keeping the answer simple (i.e., no thesis), boxed frames are far superior to C channel frames in torsional rigidity and that rigidity is what assists suspension components in doing their job, and thereby improving handling. Have you ever noticed how a C channel ladder frame twists over obstructions. My '97 bed would contact the cab in severe offroad use...that's a lack of torsional rigidity.

Also, boxed frames permit the frame crossmembers to be "through rail" welded, a tremendous strength advantage over C channel frames.

C channel frames (and I beams) have excellent sheer strength. That's important to trucks, rail cars, etc., but those vehicles don't require the precise suspension dynamics of a passenger vehicle.