Single vs. Tandem Rear Axles?

[oceans]

I’m going to be in the market for a heavier truck pretty soon. I’m now holding a Class A CDL, and I’m thinking about building a good sized hooklift to take the place of my 3 different 26,000 GVWR trucks.

I’ve seen some nice single rear axle trucks with a pusher lift axle, but there are far more tandems on the market. There’s also a truck shop nearby that can alter axles and re-certify the truck with a new pillar sticker. This makes for lots of options.

My main questions are:
- Does a single get significantly better fuel economy vs. a tandem?
- What is the difference in ride quality when loaded AND unloaded?
- How does a tandem affect steering maneuverability and potential damage to driveways, etc…?
- Any other thoughts are welcome.

Also consider I may be pulling a 15 ~ 20 ton tag trailer with a load on the truck as well. Another goal for the day to day jobs is to get all my stuff to the job in one trip and leave with equipment and materials.

Thanks for any input.

 

[evo]

I can’t answer from too much experience so please take that into account.
Fuel mileage- No clue
Ride quality- loaded better, unloaded ?
Maneuverablity- certainly more limited- impact somewhat more improved as better weight dispersal

I’d look at a single axle with a tag, but if going with a tandem rear get one that is dual drive for those off road times

 

[oceans]

I can’t answer from too much experience so please take that into account.
Fuel mileage- No clue
Ride quality- loaded better, unloaded ?
Maneuverablity- certainly more limited- impact somewhat more improved as better weight dispersal

I’d look at a single axle with a tag, but if going with a tandem rear get one that is dual drive for those off road times

I do look for the full locking rears on the tandems. That’s pure 6x4, but I’m not sure how much I’d really need it. I’ve been ok with 4x2 in all 3 class 6 trucks so far.

 

[Alec A.]

I used to drive a tandem rear axle, setvice body, rear mount 75ft Altec bucket when I worked at the City of Portland. It was a bear to park anywhere tight, the rear axle interlock was cool, but wouldn't get the rig unstuck. Our work was mostly ROW and in parks, that truck was too big to do anything residential though. Seems like even in CDL truck territory, a more nimble and shorter single axle rig with a tag would be more versatile.

 

[evo]

I do look for the full locking rears on the tandems. That’s pure 6x4, but I’m not sure how much I’d really need it. I’ve been ok with 4x2 in all 3 class 6 trucks so far.

As long as you have rear tandem lockers no need for the front. You can push your way out of pretty much anything

 

[Jehinten]

This is my current setup, I cannot specifically answer all of your questions as this is my first cdl truck.

From my experience, the ride in the truck is fine although suspension type will likely play a bigger role than number of solid axles. Mine is spring suspension without airbags. When loaded heavy it does feel a little tippy due to heavy logs typically go on top creating a higher center of gravity.

My truck has the dual drive rear axles with axle lock. I've only gotten it stuck twice. Once I raised it enough with the outriggers to get boards under the tires, the other time I went back out in the middle of the night once the ground was frozen. All other times the axle lock and selecting a low gear has gotten me through some muddy dump sites.

I've never had any damage to a driveway due to the tandem axle.

Maneuverability: it's no F1 racer, but it can complete a U-turn in most cul- de-sacs, even with the 16' car hauler behind it.

 

[oceans]

I used to drive a tandem rear axle, setvice body, rear mount 75ft Altec bucket when I worked at the City of Portland. It was a bear to park anywhere tight, the rear axle interlock was cool, but wouldn't get the rig unstuck. Our work was mostly ROW and in parks, that truck was too big to do anything residential though. Seems like even in CDL truck territory, a more nimble and shorter single axle rig with a tag would be more versatile.

True, and I think I agree, but I also think about all the large cranes and grapplesaw trucks that are used routinely in residential work that somehow make the squeeze.

Do you think the wheelbase was much of the woes of that big truck or the actual tandems?

A guy near me has a new-ish Peterbilt 348 with a heavy front, a single rear and a pusher. He hauls pretty heavy and I don’t often see the lift axle on the ground unless he’s full of soil in the dump body. I just can’t find a truck for sale that’s soec’d that way.

 

[oceans]

View attachment 97937
This is my current setup, I cannot specifically answer all of your questions as this is my first cdl truck.

From my experience, the ride in the truck is fine although suspension type will likely play a bigger role than number of solid axles. Mine is spring suspension without airbags. When loaded heavy it does feel a little tippy due to heavy logs typically go on top creating a higher center of gravity.

My truck has the dual drive rear axles with axle lock. I've only gotten it stuck twice. Once I raised it enough with the outriggers to get boards under the tires, the other time I went back out in the middle of the night once the ground was frozen. All other times the axle lock and selecting a low gear has gotten me through some muddy dump sites.

I've never had any damage to a driveway due to the tandem axle.

Maneuverability: it's no F1 racer, but it can complete a U-turn in most cul- de-sacs, even with the 16' car hauler behind it.

Wow! I remember you posting about this truck when you first got it. It sounds like it’s really working well for you.

Curious if you happen to know the wheelbase from the front axle to the center of the 2 rears? I’m thinking of trying to stay around 220” ~ 230”.

 

[Jehinten]

Wow! I remember you posting about this truck when you first got it. It sounds like it’s really working well for you.

Curious if you happen to know the wheelbase from the front axle to the center of the 2 rears? I’m thinking of trying to stay around 220” ~ 230”.

I do not, but I can get that answer for you tomorrow.

Yes this setup has been working great. The trailer carries every tool I need. Everything to and from the job in one trip.

 

[oceans]

I do not, but I can get that answer for you tomorrow.

Yes this setup has been working great. The trailer carries every tool I need. Everything to and from the job in one trip.

What all is in the trailer?

My kit includes:
- C10 Spider Crane (10,400 lbs)
- E55 Excavator (11,000 lbs)
- Attachments: Grapple, Feller Buncher Head, Drum Mulcher, Stump Planer & Augers. (2,200 lbs)
- 12” Drum Chipper (5,000 lbs)

Not every job requires all this, but some do. This is why I think the hooklift and heavy tag trailer setup will be the best for me.

 

[Jehinten]

Curious if you happen to know the wheelbase from the front axle to the center of the 2 rears? I’m thinking of trying to stay around 220” ~ 230”.

Measured as shown in the pic. My truck is 245"

 

[Jehinten]

What all is in the trailer?

My kit includes:
- C10 Spider Crane
- E55 Excavator (11,000 lbs)
- Attachments: Grapple, Feller Buncher Head, Drum Mulcher, Stump Planer & Augers.
- 12” Drum Chipper

Not every job requires all this, but some do. This is why I think the hooklift and heavy tag trailer setup will be the best for me.

It's a little messy right now, but I have a workbench with vice (this one is temporary and will be replaced once the permanent one comes back from being planed at a woodworking shop) chain and 2 cycle oil storage, a microwave for hot lunches.

Mini skid storage, axe and pole storage, bmg rake and a space under the work table for either a second grapple or a hydraulic winch. Typically I carry the second grapple.

The other side is shelving for all climbing, rigging and gas powered tools. Behind the shelves is storage for ground mats. Currently I have 6 mats on board but I'll be sliding the shelves out a few more inches for 12 mats.

The trailer is wired for 12v and 120v lights and 120v receptacles should I plug into a customer's power or fire up the generator.

A consideration for me was the ability to walk through the trailer to grab gear without having to unload the mini skid and good lighting for sharpening saws at night without hauling them across the lot to the shop. The 16' enclosed car hauler allows this with the wider interior than a typical enclosed plus the ramp is heavier duty. 16' length is the max I can haul and get into my property as I live on a boulevard and I have to back in perpendicular to the road.



With this setup I haul every tool to every job with the exception of sometimes swapping a grapple for the winch and for now occasionally adding more mats.

 

[oceans]

@Treetopflyer , what do you have to say on the subject now that you’re rollin on Swedish steel?

 

[oceans]

It's a little messy right now, but I have a workbench with vice (this one is temporary and will be replaced once the permanent one comes back from being planed at a woodworking shop) chain and 2 cycle oil storage, a microwave for hot lunches.

Mini skid storage, axe and pole storage, bmg rake and a space under the work table for either a second grapple or a hydraulic winch. Typically I carry the second grapple.

The other side is shelving for all climbing, rigging and gas powered tools. Behind the shelves is storage for ground mats. Currently I have 6 mats on board but I'll be sliding the shelves out a few more inches for 12 mats.

The trailer is wired for 12v and 120v lights and 120v receptacles should I plug into a customer's power or fire up the generator.

A consideration for me was the ability to walk through the trailer to grab gear without having to unload the mini skid and good lighting for sharpening saws at night without hauling them across the lot to the shop. The 16' enclosed car hauler allows this with the wider interior than a typical enclosed plus the ramp is heavier duty. 16' length is the max I can haul and get into my property as I live on a boulevard and I have to back in perpendicular to the road.



With this setup I haul every tool to every job with the exception of sometimes swapping a grapple for the winch and for now occasionally adding more mats. View attachment 97942View attachment 97943View attachment 97944

Trade the grapple truck for an F350 and remove the mini from the trailer and that’s where I was in my early days. It’s essentially a massive toolbox but also a workspace. I love it and can totally remember how much I loved having everything right there. Having the mini and grapple truck makes for a really well rounded kit. If I went that direction, I might think about finding a wallboard truck and putting sides on it.

 

[Merle Nelson]

@Lumberjack/Carl has been living the choice between single and tandem axle for some time I believe.

 

[Treetopflyer]

@Treetopflyer , what do you have to say on the subject now that you’re rollin on Swedish steel?

You putting a knuckle boom crane on this rig brother?

 

[Lumberjack]

I’m going to be in the market for a heavier truck pretty soon. I’m now holding a Class A CDL, and I’m thinking about building a good sized hooklift to take the place of my 3 different 26,000 GVWR trucks.

I’ve seen some nice single rear axle trucks with a pusher lift axle, but there are far more tandems on the market. There’s also a truck shop nearby that can alter axles and re-certify the truck with a new pillar sticker. This makes for lots of options.

My main questions are:
- Does a single get significantly better fuel economy vs. a tandem?
- What is the difference in ride quality when loaded AND unloaded?
- How does a tandem affect steering maneuverability and potential damage to driveways, etc…?
- Any other thoughts are welcome.

Also consider I may be pulling a 15 ~ 20 ton tag trailer with a load on the truck as well. Another goal for the day to day jobs is to get all my stuff to the job in one trip and leave with equipment and materials.

Thanks for any input.

I have a single axle with a tag hook lift truck and a tandem with a tag grapple truck.

Fuel economy is a function of weight, speed, and acceleration, aerodynamics are a brick either way. 350hp automatic on the hook lift, 505hp and 12 speed automated on the grapple truck. Empty they weigh ~18klb/~40klb.

My hook lift rides better than my grapple truck, a 13klb front end vs 20klb and their associated tires plus better cab suspension is my guess.

Steering is mainly a function of wheelbase....short wheelbase is why I built the hooklift as I did with the tag axle. The tag axle down does affect steering. On slick ground the grapple truck's wide front tires are prone to slide vs steer... that's worse with the tag down. Locking differentials really affects steering... the more axles that are locked, the worse it is.

Driveway damage is essentially tire psi/tire loading and transitioning off and on the pavement (keep the weight away from the edge). For going from the yard to driveway, get the steer axle on the concrete, then drop the tag axle to take weight off the drive(s)/spread the weight on to more tires. Putting a tag down transfers weight to the steer.

In general, I'm a fan of tax axles. It allows a shorter wheelbase while maintaining the option to move weight to the steer axle and puts the axle in the best spot for heavy pintle trailers. Both of my trucks have 50 ton pintles with a 20klb max vertical load capacity.

Legalities start becoming a thought with a heavy trailer, equipment, and materials, assuming the material is tree debris. My day to day trailer load has a ASV RT40, Rayco RG80, and a Dino 92RXT, roughly 26klb. Add that to the 40klb grapple truck and you're at 66klb before any debris. The hooklift with the trailer hauling the ex, larger track loader, and stump grinder comes in at 72klb.

I want to add a 20T and/or 30T trailer(s) to my setup for hauling more and heavier equipment. The dozer and excavator weigh ~46klb combined, or the ex and lift are ~34klb. Heavier equipment in the future seems likely.

I've been pondering what I would add/change next.... build the grapple truck I want, or buy a semi tractor and trailers are the two most obvious choices.

 

[oceans]

You putting a knuckle boom crane on this rig brother?

Yes, but not anything huge. A long 30 with a jib and a couple manuals would be plenty for me.

THe other thought kicking around is still to set up a wallboard style truck as a do-all beast.

 

[FJR]

I have a single axle with a tag hook lift truck and a tandem with a tag grapple truck.

Fuel economy is a function of weight, speed, and acceleration, aerodynamics are a brick either way. 350hp automatic on the hook lift, 505hp and 12 speed automated on the grapple truck. Empty they weigh ~18klb/~40klb.

My hook lift rides better than my grapple truck, a 13klb front end vs 20klb and their associated tires plus better cab suspension is my guess.

Steering is mainly a function of wheelbase....short wheelbase is why I built the hooklift as I did with the tag axle. The tag axle down does affect steering. On slick ground the grapple truck's wide front tires are prone to slide vs steer... that's worse with the tag down. Locking differentials really affects steering... the more axles that are locked, the worse it is.

Driveway damage is essentially tire psi/tire loading and transitioning off and on the pavement (keep the weight away from the edge). For going from the yard to driveway, get the steer axle on the concrete, then drop the tag axle to take weight off the drive(s)/spread the weight on to more tires. Putting a tag down transfers weight to the steer.

In general, I'm a fan of tax axles. It allows a shorter wheelbase while maintaining the option to move weight to the steer axle and puts the axle in the best spot for heavy pintle trailers. Both of my trucks have 50 ton pintles with a 20klb max vertical load capacity.

Legalities start becoming a thought with a heavy trailer, equipment, and materials, assuming the material is tree debris. My day to day trailer load has a ASV RT40, Rayco RG80, and a Dino 92RXT, roughly 26klb. Add that to the 40klb grapple truck and you're at 66klb before any debris. The hooklift with the trailer hauling the ex, larger track loader, and stump grinder comes in at 72klb.

I want to add a 20T and/or 30T trailer(s) to my setup for hauling more and heavier equipment. The dozer and excavator weigh ~46klb combined, or the ex and lift are ~34klb. Heavier equipment in the future seems likely.

I've been pondering what I would add/change next.... build the grapple truck I want, or buy a semi tractor and trailers are the two most obvious choices.

Great post Carl. There is a lot of good information in there. I would love to hear your thoughts on how you would spec and build out your future grapple truck.

Sent from my SM-S916U using Tapatalk

 

[oceans]

I have a single axle with a tag hook lift truck and a tandem with a tag grapple truck.

Fuel economy is a function of weight, speed, and acceleration, aerodynamics are a brick either way. 350hp automatic on the hook lift, 505hp and 12 speed automated on the grapple truck. Empty they weigh ~18klb/~40klb.

My hook lift rides better than my grapple truck, a 13klb front end vs 20klb and their associated tires plus better cab suspension is my guess.

Steering is mainly a function of wheelbase....short wheelbase is why I built the hooklift as I did with the tag axle. The tag axle down does affect steering. On slick ground the grapple truck's wide front tires are prone to slide vs steer... that's worse with the tag down. Locking differentials really affects steering... the more axles that are locked, the worse it is.

Driveway damage is essentially tire psi/tire loading and transitioning off and on the pavement (keep the weight away from the edge). For going from the yard to driveway, get the steer axle on the concrete, then drop the tag axle to take weight off the drive(s)/spread the weight on to more tires. Putting a tag down transfers weight to the steer.

In general, I'm a fan of tax axles. It allows a shorter wheelbase while maintaining the option to move weight to the steer axle and puts the axle in the best spot for heavy pintle trailers. Both of my trucks have 50 ton pintles with a 20klb max vertical load capacity.

Legalities start becoming a thought with a heavy trailer, equipment, and materials, assuming the material is tree debris. My day to day trailer load has a ASV RT40, Rayco RG80, and a Dino 92RXT, roughly 26klb. Add that to the 40klb grapple truck and you're at 66klb before any debris. The hooklift with the trailer hauling the ex, larger track loader, and stump grinder comes in at 72klb.

I want to add a 20T and/or 30T trailer(s) to my setup for hauling more and heavier equipment. The dozer and excavator weigh ~46klb combined, or the ex and lift are ~34klb. Heavier equipment in the future seems likely.

I've been pondering what I would add/change next.... build the grapple truck I want, or buy a semi tractor and trailers are the two most obvious choices.

Thanks for such a thorough post!

I understand your point about the tag transferring weight to the steer axle, and being an advantage to lift it and reduce turning radius. I had thought the same thing but a friend of mine swears by a pusher because he had a tag that kept him from backing up to a dump location within a landscape…the drive axle kept losing traction even with the tag lifted. The pusher doesn’t have this issue for him. His situation doesn’t sound like something I would ever encounter, but it is all food for thought And I originally leaned on the tag location.

With all that said, it may be that I just settle on a tandem rear and be done with it. I still don’t know. Being mostly a one man band can be a bit of a thing, can’t it?