Dually questions

[ssgoodman]

i found a cheap dually parts truck for sale, its a decent price but had questions.  its a 2 wheel drive but what kind of rear end would it have in it?  its a 77 c30 dually.  would it be possible to swap that rear end into my jimmy or are the dually axles different?

Thanks
SUtton

[mike in mo]

missing some info here i dont know what your jimmy is but i know a 1 ton rear dont fit under a 1/2 or3/4 ton truck. what rearend is it well its a 14bolt gm or a dana 70. most CC trucks are 14 bolt and as far as i know all the pick up box trucks had the dana70 under them.

[ssgoodman]

i have a 1990 GMC Jimmy fullsize but it has the 10 bolt rear end.  i am dreaming of making it a good offroader and dont think the 10 bolt would hold up vary well to what i want to put it through.  i wanted to put either a 12 bolt or a 14 bolt on the rear end since it would hold up better to off roading.  i seen the dually on Craigslist and thought about buying the rear end off the guy but wasnt sure if it would work with a single rear wheel vehicle.  i dont want to run duals i just want a tough rear end but i didnt know if you could run a single rear wheel with a dually rear end without changing the shafts over.

[HAULIN IT]

Goodman, One thing to get clear on. This truck is a "dually", not a "cab & chassis" truck, Correct? Now, from there I'm going out on a limb slightly, so don't take this for gospel truth (investigate a little further). I think what Mike is referring to is the "cab & chassis" rear. I believe they are narrower at the spring perches (the total length is narrower). I'm thinking a regular "dually" rear will bolt in & with a normal (single type) wheel this would work in the Blazer. You may have to play with wheel spacing or a spacer if you are concerned with how it looks. Anyone else with "for sure" knowledge please help! What I'm saying is a collection of things over a period of 20 years (we have a wrecker with a "cab & chassis" rear under a regular truck that was built many years ago, from "Hey, you sent me the wrong rear" conversations during repairs & I also know a guy who bought a dually bed & wheels when he re-did his truck 1 ton single wheel truck & everything looked correct, but I don't know if there were adapter/spacers involved) so don't burn me at the stake if some of this is wrong. Ok? Lorne   

[Blazin]

A dually rear end will bolt in to the perch's no problem. A cab and chassis rear end will also bolt in but the over all width is narrower.

[ssgoodman]

thanks for the replies, yeah it is a true dually with a box on it.  i wasnt aware there was a difference between duallys and cab/chassis, i thought they were just duallies without the box on it. the guy wants 700 bucks for the rear end though so i think its all a moot point.  i dont really want to spend that much on a rear end when my current one works ok.  i found them other places for cheaper then this guy wants.

[Stewart G Griffin]

i began to notice that there were 2 different axle widths---cab/chassis and pickup around the time when i worked at the truck salvage yard.

So, i guess this begs the obvious question-----why 2 different widths?  i have seen a few pickups with the narrower rear in the city;  i don't mean to say that they (the setup) is "ghetto."  But the trucks were kind of shabby and rough looking---mostly hauling junk around.  They still needed  fender flares , but both tires seemed to fit under the stock wheel wells without modifications.

[HAULIN IT]

You are correct Stewart. We have '77 towtruck that has a dually rear w/ bud wheels under a normal bed. It is a 4x4, lifted slightly so the wheelwells aren't an issue, if you want it stock height 2wd, the wellwells need split (kinda like a pro streeter, just about 1 1/2") A full sheet of plywood no longer lays between them though. On the wrecker are the narrow 2 1/2" or so Bushwacker flares & everything is under them. I believe the wheels are early '70's? narrower or less offset than the later ones. Someday I'll grab a few pictures of it, the back is cut off behind the spring hanger & the bedsides sectioned back on. A fellow I know did a 2wd, it had rather narrow tires & just wheel opening moldings. The bulge of the tire was sticking out, but not the tread. Later, Lorne       

[Stewart G Griffin]

i'm beginning to surmise that the reason why pickups have the wider rear is so that the bed capacity won't be compromised;  i notice that Ford and Chrysler (and possibly Toyota?) also do the same.

2)To confuse the issue further, i don't know if it's still being done, but a few aftermarket RV manufacturers would take a cutaway van chassis and put a pickup bed on the back so what you would end up with was sort of a van-pickup mainly used to haul fifth-wheel trailers.   They looked real cool, but the point is that here too, both of the wheels fit nicely under the wheel wells and fender flare which appears to be the same as a stock dually pickup.  i wonder if this rear axle is the same width as the pickup's or totally different?

a) What is the advantage(if any) of a cutaway van chassis/pickup vs. a regular dually pickup?

[Dragon]

i'm beginning to surmise that the reason why pickups have the wider rear is so that the bed capacity won't be compromised;  i notice that Ford and Chrysler (and possibly Toyota?) also do the same.

From what was covered in my Auto Collision Training, it has to do with the fact that a truck with a standard box is able to have the Outer Dually Rear Tires covered by flares.. Where as a Cab Chassis truck usually would have the flat/stake bed no/not much wider than the cab itself, thus leaving the outer wheels exposed...   

It is also my understanding is that they could be ordered with Standard or Narrow Rears, to give them a better weight distribution, depending on their use... Especially if the truck was going to get an Enclosed Box, such as a Camper or Frieght Box...