dually rims on an 85 c20??

[87454westernhauler]

not sure if it would work but i have a set of rims and tires still from my dads old 79 c3500 dually and i am needing tires for my 85 c20 3/4 ton. the tires off of the dually are the 16.5 so i couldnt just swap tires around. so would the dually rims fit on the front end without changing hubs? i dont think that it would be a wise idea to use a single dually rim on the back or would it?

[zieg85]

Dually rims won't work on the front and not a good idea for the back because it will stick out and sling stuff everywhere.  I see 16.5 rims on CL quite often and most are real cheap as no one wants them.

[87454westernhauler]

im guessing i would need to get spacers it i were to put then on the front.

[zieg85]

im guessing i would need to get spacers it i were to put then on the front.

2 wheel drive dually front rotors would be best. 

[87454westernhauler]

i still have the entire front end out of the dually. would i need to change the spindels too?

[zieg85]

i still have the entire front end out of the dually. would i need to change the spindels too?

Don't know on the newer trucks.  I know it was a direct change over on a 1972 C30.  Compare the 2 applications on AutoZone's website.  Compare things like brake pads, calipers, wheel bearings, seals...

[Jason S]

Based on the limited resources I have on hand for GM part numbers:

The C30 (1 ton) steering knuckles (spindles) carry different part numbers than those for the C20 (3/4 ton). The ball joints have the same part number for the 1 ton and 3/4 ton.

The upper control arms could be the same.  The part numbers show the heavy duty 1 ton upper control arms to carry a different part number.  The lower control arms carry the same part number. I suspect the heavy duty upper control arms were for a dually. But that may not be an issue with your swap, just measure.  The lower control arm brackets and the lower control arm shaft for a 1 ton show different GM numbers than the 3/4 ton.

For the front calipers, the GM part numbers are different based on a hydroboost vs. vacuum booster and 11" or 13" rear brakes.

The rear axle for a fleetside dually truck is different than for a single wheel 1 ton or 3/4 ton or chassis cab. Dual rear wheels can fit on a single rear wheel axle, but you have wheel & tire hanging out the fender well. 

Overall - between the two trucks, you could probably put something together to run the dually rims on your C-20.

Do you ultimately want to have a dually?  Sounds like an awful lot of work just for tires.  Hopes this helps a bit.

[87454westernhauler]

well right now its my daily driver. the 3/4 ton rear end is starting to get slop in it and i kept the front suspension, dually fenders and almost new rear end out of the 79 when i scraped it. in the end if i keeep this going truck, i kind of want to make it into a dually. but im not shure if i have to change the spindels out on the front end or if the rotors are exstangable! if they are exchangable it would save a lot of work.

on the rear end swap, how easy would that be and how compadable are the mounts? 

[Jason S]

I think the spring pad width on the cab & chassis dually 14 bolt are different than the SRW or pickup box DRW 14 bolt.  If your dually rear was from a 1 ton with a dually fender pickup bed, then it should be a bolt in deal. A couple minutes measuring the distance from the center of one rear leaf spring to the center of the other rear leaf spring on your 1 ton rear end and 3/4 ton rear end should tell you for sure. 

http://forum.73-87chevytrucks.com/smforum/index.php/topic,10081.0.html

Also double check the width of the spring pad and/or leaf spring and make sure they are the same width.  If the spring pad width is different you'll need to swap out the pad for one with the correct width. If the distance from pad to pad are different but the spring pads are the correct width, then you'd need to cut the pads off and locate them to the correct distance.   

For the front, I'd think you'd need to at least change to 1 ton parts from the from the spindle/steering knuckle out to the wheel (Including calipers, brackets, hubs, rotors, etc.). Alternatively, you could swap everything from the 1 ton front end (upper and lower control arms, brackets, etc.) and have all the correct 1 ton parts up front.   

There ought to be others on here that have a more definite answer for you. 

[bigchevyc30]

the spindels are not the same with the c20s to the c30 as with duallys they have a different looking rotor than say the regular truck. with duallys they have a huge chink of metal to help offset the actual wheel for say the rear so it rides right when going down the road


if you do go to change brakes there are 2 sets of brakes you could choose from for your truck if you switch to 1-ton as there is the jb-7 and jb-8 brakes jb-8 is the kind my dually has and its got biggers pads and shoes than say the jb-7. also that i have red if you do do jb-8 then you will have to convert from vacuem boost to hydro-boost which if you do i can get you all the pictures u need to get it done. if it were most people they would go to a junkyard and get the stuff of a old dually and by things from "autoszone, napa, advance, oreillys's" or where ever you prefere to get the barrings seels joints and things like that if you have trouble figuring out if the truck you get stuff off heres what the jb-8 brake pads look like


hope this helps