Converting single Rear to Dual Rear On OBS

[Waystro]

So I told a friend I would ask about this.
He has a OBS and wants to convert single to duals would he have to do a Axle swap or is there anyway to do this with out swapping axles?

 

[LCAM-01XA]

The "dirty" way is to install a pair of 3" thick adapters on the SRW hubs, then slap the duals on those. Not recommended if he plans to actually put the DRW setup to proper use, as now all the load from the wheel pair is sitting directly on the outer hub bearing, instead of between the inner and the outer like how the factory setup (both SRW and DRW) does it.

The proper way would be to swap a complete DRW axle. Must come out of a DRW truck with a pickup bed, as cab-chassis have narrow frames and also narrow rear axles.

 

[Waystro]

Thanks that's what I thought. Swapping Axle would be best.
Since I would be doing it for him. Is pretty much a Straight forward job?

 

[LCAM-01XA]

Yup, sure is. Two shocks + swaybar endlinks + two e-brake cables + one brake hose + one VSS harness + one axle vent hose to disconnect, and 4 U-bolts to cut (4.5" cutoff wheel works awesome). If the new axle is from the same model years and donor truck has the same style engine and transmission then driveshaft should bolt right on, if not you may need a conversion U-joint for the axle yoke. Also now would be a good time to alter the rear ride height with taller or lower blocks, if so desired...

 

[Dsl_Dog_Treat]

The "dirty" way is to install a pair of 3" thick adapters on the SRW hubs, then slap the duals on those. Not recommended if he plans to actually put the DRW setup to proper use, as now all the load from the wheel pair is sitting directly on the outer hub bearing, instead of between the inner and the outer like how the factory setup (both SRW and DRW) does it.

The proper way would be to swap a complete DRW axle. Must come out of a DRW truck with a pickup bed, as cab-chassis have narrow frames and also narrow rear axles.

FWIW my dually has the Arrow Craft adapters front and rear and was like that when I bought it 10 years ago. The truck was converted and used as a municipal service truck prior, with a utility bed on it, and after going back to civilian use, it's hauled fivers since. My current fiver weighs in at 11,300 empty and the truck has been used in excess of it's GCVW capacities numerous times and the adapters show no signs of fatigue or failure. It's a safe option and can be a cost effective mod IMHO.

 

[towcat]

FWIW my dually has the Arrow Craft adapters front and rear and was like that when I bought it 10 years ago. The truck was converted and used as a municipal service truck prior, with a utility bed on it, and after going back to civilian use, it's hauled fivers since. My current fiver weighs in at 11,300 empty and the truck has been used in excess of it's GCVW capacities numerous times and the adapters show no signs of fatigue or failure. It's a safe option and can be a cost effective mod IMHO.

there's a few states that won't allow the truck to be considered in the same weight class when a dually convertor is used. WA state is one and they will stop you cold at the port of entry too.

 

[Dsl_Dog_Treat]

there's a few states that won't allow the truck to be considered in the same weight class when a dually convertor is used. WA state is one and they will stop you cold at the port of entry too.

Whats odd with the 2 trucks I had Cal, both were crew cab duallies one and 89 4x2 , the other a 90 4x4 and both had the same gvwr on them and I kept getting whacked commercial fees on the 90 and paid 3 times the reg fees.

 

[towcat]

Whats odd with the 2 trucks I had Cal, both were crew cab duallies one and 89 4x2 , the other a 90 4x4 and both had the same gvwr on them and I kept getting whacked commercial fees on the 90 and paid 3 times the reg fees.

honestly, how MI calcs their bridge loads is out of step with the rest of the world. Only MI will you see a dumptruck with axles from front to rear. those trucks are illegal in the rest of the country.
btw.... out in kali, the reg fees for a CC dually 4x4 is $300/yr.

 

[LCAM-01XA]

FWIW my dually has the Arrow Craft adapters front and rear and was like that when I bought it 10 years ago. The truck was converted and used as a municipal service truck prior, with a utility bed on it, and after going back to civilian use, it's hauled fivers since. My current fiver weighs in at 11,300 empty and the truck has been used in excess of it's GCVW capacities numerous times and the adapters show no signs of fatigue or failure. It's a safe option and can be a cost effective mod IMHO.

Cool, good to know someone has proper heavy-use experience with them and they held up fine! But there is the legality issue as Towcat mentioned... Just yet another thing to consider I guess, but but even so it's still better than most of Europe where God forbid you even think of installing a lift kit on you truck

Whats odd with the 2 trucks I had Cal, both were crew cab duallies one and 89 4x2 , the other a 90 4x4 and both had the same gvwr on them and I kept getting whacked commercial fees on the 90 and paid 3 times the reg fees.

Was the '90 a 4x4 conversion of a pickup truck, or a factory 4x4? If it was factory that means it was a cab-chassis truck, so possibly automatic commercial status at the DMV? Now if both we pickup-framed, or both were cab-chassis, then it would make no sense for one to be commercial and the other not.

honestly, how MI calcs their bridge loads is out of step with the rest of the world. Only MI will you see a dumptruck with axles from front to rear. those trucks are illegal in the rest of the country.

Yet even with the load spread across so much rubber their "paved" roads are still so bad that after only half an hour on them one seriously begins to consider getting off the interstate and running the dirt roads instead... US-23 comes to mind here, you really don't need the sign to tell you when you crossed from OH into MI Ironically I80 is the same way within a single state in some areas, you immediately know when you cross between poor counties and more well-to-do ones.

 

[Dsl_Dog_Treat]

Cool, good to know someone has proper heavy-use experience with them and they held up fine! But there is the legality issue as Towcat mentioned... Just yet another thing to consider I guess, but but even so it's still better than most of Europe where God forbid you even think of installing a lift kit on you truck


Was the '90 a 4x4 conversion of a pickup truck, or a factory 4x4? If it was factory that means it was a cab-chassis truck, so possibly automatic commercial status at the DMV? Now if both we pickup-framed, or both were cab-chassis, then it would make no sense for one to be commercial and the other not.


Yet even with the load spread across so much rubber their "paved" roads are still so bad that after only half an hour on them one seriously begins to consider getting off the interstate and running the dirt roads instead... US-23 comes to mind here, you really don't need the sign to tell you when you crossed from OH into MI Ironically I80 is the same way within a single state in some areas, you immediately know when you cross between poor counties and more well-to-do ones.

She's gotten a god workout since I've owned it and the PO I bought the truck from just used it to haul his fiver.
The truck was originally a factory crew cab long bed 4x4 so no cab and chassis dealings there. It was nice to get a folder that was 3" thick of paperwork on the entire history of the truck when I bought it.
Just an oddball truck I guess.