Frame Rails:

[Rob]

Does anyone know if there is any difference in the rails of an R-700 series, and an R-600 series? I'm not asking about crossmembers or attaching mounts, just the basic rails. The two I'm looking at are both 10 inches tall, and flared wider at the front.

Thanks,

Rob

[terry]

Should be some different dimensions on the front on length, i think the R700 had the longer hood, than the R600. terry

[David]

Rob,

The 80's spec sheets I have show the R600 and R700 both with 9.00"x3.25"x.25" frames.

The 1978 sales engineering publication on frames shows the R400,R600,R700ST,U600 and U700 also with this same frame. The R700S(standard) is 10.5"x3.25"x.25". The R700S(optional) is 10.62"x3.25"x.312". The RD400,RD600 and RD700 is 10.62"x3.25"x.312". All have a .25" inside member available that starts 15" behind the center of the front axle. From the drawings (no dimension shown) only the R400,R600,R700ST,U600 and U700 show a vertical drop in the front that starts about at the rear of the cab. There also is a disclaimer that states "illustrations are not necessarily a representation of standard specifications".

Hope this helps,

David

[Rob]

Rob,

The 80's spec sheets I have show the R600 and R700 both with 9.00"x3.25"x.25" frames.

The 1978 sales engineering publication on frames shows the R400,R600,R700ST,U600 and U700 also with this same frame. The R700S(standard) is 10.5"x3.25"x.25". The R700S(optional) is 10.62"x3.25"x.312". The RD400,RD600 and RD700 is 10.62"x3.25"x.312". All have a .25" inside member available that starts 15" behind the center of the front axle. From the drawings (no dimension shown) only the R400,R600,R700ST,U600 and U700 show a vertical drop in the front that starts about at the rear of the cab. There also is a disclaimer that states "illustrations are not necessarily a representation of standard specifications".

Hope this helps,

David

Thank you guys for the help. I've have an 82 R-686 frame on air ride that is single frame, .312 thickness, 3.25" in width, and is 10.5" in height. It is physically longer than the R-795 that I have which has the same dimensions except is double framed with the .250" inside support, and severe rest spreading. The only drawback is the long framed truck had a cab and engine fire which burnt the paint off of it. I don't know if it was hot enough to weaken or not. Although I do not have it, the engine was salvaged and I'm told runs well. There are no sags and it sets level on concrete. Also, the R-795 frame is 33" in rear external width, and the R-686 frame is 34" rear external width. This one inch difference is consistent from front to rear.

Most of the crossmembers on the R-795 are structurally weakend from rust. I'm thinking that I would need to cut and narrow by .500" the crossmembers on the donor frame, glove the inner side with .250" material, and then bolt everything back together. A lot of work I know, but most of this labor was planned for anyway.

Again, I appreciate the help.

Rob