3/4 ton to dually conversion

[Yukon Jack]

My friend Tony with the 70 1 ton converted to 4wd gave me the following information:

He said ideally get a later dually 4x4 for the front axle or you have to go with aftermarket adapters to make a front axle from a single rear wheel truck work - Tony found out of state adapters for about $450 with shipping to make the front axle correct for the dually rearend. His tires are 235 85 16

The 70 1 ton was a dually rearend originally but he did not use it as it had 5.14 gears in it.

Tony is using the donor 71 GMC's 3/4 ton’s single rear wheel axle and to make it work he is using the inside dually split rim that was on the 1970's dually axle. The new dually rims are dished differently. By using the 71's rear end he had to use the 70's stock split rim to clear the drum brakes.

[WIDESIDE72]

I figure that this thread has been dead long enough! LOL. I have a 70 Longhorn that I will be setting a utility bed and small welder on. I got a sweet deal on a set of 19.5 dually wheels and tires off a p30 frito truck. Now the fun begins! I also recently acquired a a disc front crossmember out of an 85 c20, for its disc brakes. I believe i can swap the 19.5's on back pretty easily. (Granted the dana 60 under the 70 has 1/2" studs, but i dont believe it should matter with tapered lugs. If so, i can drill and install 9/16" studs, or i have an 8 lug rear out of a 71 or 72 c20 with 9/16" studs that i can swap in. My main concern is the front. Plan A is to buy the oem cast iron dodge dually spacers and bolt them on the drums on the truck now, then use them on the 85 disc rotors later, since patience really isnt my thing.�� (The truck is a driver and whats the point of having cool 19.5" wheels if they are sitting in the shed?) the trouble is, all of those adapters i have found will cost me around $250 shipped. Does anyone have a better source? Plan B involves buying c30 style rotors for the 85 crossmember and waiting on the wheel swap til then. Instant gratification delayed! Advance auto has a 25% off sale today and i can get both dually rotors shipped to me free, total of about $202. Trouble is I am not 100% sure the c30 dually rotors will bolt up to the c20 spindles and calipers correctly. Anyone?

[WIDESIDE72]

Does anyone have experience running the oem dodge dually adapters on the c20 drum brake hub?

[WIDESIDE72]

Well I rolled the dice on a pair of dodge fromt adapters and it turns
Out that They are intended for A wheel with a 4.75" center, whereas the p30 19.5" wheels I have only have a 4.5" center, so those will be going for sale on ebay.

[junksaver]

I wish I would have seen this thread earlier. I tried the same thing and it didn't work. Luckily I was able to borrow the adapters off a friend to try them out. I don't think there is a way to run dually wheels on 3/4 ton rotors.

[LockDoc]

Originally Posted by WIDESIDE72

Well I rolled the dice on a pair of dodge fromt adapters and it turns
Out that They are intended for A wheel with a 4.75" center, whereas the p30 19.5" wheels I have only have a 4.5" center, so those will be going for sale on ebay.

Any reason the center of the wheels couldn't be turned to 4.75 or are there other problems....

LockDoc

[WIDESIDE72]

Originally Posted by LockDoc

Any reason the center of the wheels couldn't be turned to 4.75 or are there other problems....

LockDoc

That did cross my mind but the only machinist I trust is 4hrs away from me. In the back of my mind i have anxiety about ever needing another wheel and a stock o30 wheel not working unless i have the center bore opened up.

[WIDESIDE72]

Originally Posted by junksaver

I wish I would have seen this thread earlier. I tried the same thing and it didn't work. Luckily I was able to borrow the adapters off a friend to try them out. I don't think there is a way to run dually wheels on 3/4 ton rotors.

Southwest wheel has 4-1/2" spacers for the front and 3" for the rear, but those are over $700 for all four....
https://www.southwestwheel.com/p-1935-aa-4c.aspx
https://www.southwestwheel.com/p-1929-aa-1c.aspx
Thats more than i have in the wheels and tires, but thats the way it usually goes with bright ideas that i get myself into!

[LockDoc]

Originally Posted by WIDESIDE72

That did cross my mind but the only machinist I trust is 4hrs away from me. In the back of my mind i have anxiety about ever needing another wheel and a stock o30 wheel not working unless i have the center bore opened up.

Yeah, you would def. need to turn an extra one.....

LockDoc

[rwade]

Anyone have experience running 22” or 24” Alcoa’s with the 8 to 10 lug adapters? Wanting to use a 14 bolt 3/4 ton rear end.

Wade