Probably newbish DRW vs. Super Single questions

[ReluctantTraveler]

I've done a lot of reading on DRW vs. super singles, and most of what I come across is strongly held (often contradictory) opinions. I imagine a lot of the discussion here will also be opinion, but I'm trying to understand the pros/cons of both options.

I'm hoping to answer the question: is DRW really a problem?

There's also a second layer regarding F-350/3500 pickup DRWs vs. F-550/5500 chassis cab DRWs, as they run on different tires.

To summarize what I've read:

• DRW...
  • Provides better stability with a camper.
  • Adds some protection in the event a tire blows out, as you have another one to fallback on while you get to the shoulder and pull over.
  • Lots of commercial drivers take them on logging roads, service roads, etc. and the fear of getting a rock stuck is potential overblown.
  • They might not be as good in the snow, but good tires can compensate.
  • They suck in sand, because you can't really air them down.
• Super Singles...
  • Might handle better in the snow (though some folks say they're worse).
  • Are better in sand, because you can air them down more.
  • No risk of rocks stuck between them (but might not matter).
  • Less side-to-side stability with a camper on the bed, and if you get a blowout, that's the only tire so the rim might get wrecked.
  • Heavier and more expensive.
  • Maybe worse on highway/city roads because they're often military tires.

Some questions:

1. Are DRW F-350/3500 trucks "different" from DRW F-550/5500's because they're not on steel reinforced 19.5 pizza cutters?
2. Can you get smaller, non-military super singles? For example, Earth Cruiser's run Toyo 37's, but start their life as a DRW Isuzu NPR.
3. Are their super single conversions that aren't $20k?
4. Can you drive DRW trucks on the beach?
5. Are DRW vehicles harder to fit in a parking spot?

Apologies if this is treading tired, boring ground already covered elsewhere. I'm struggling to find clear answers, probably because so much of this is subjective.

 

[andy_b]

It would help if you distilled your questions down to specfically what you're wondering about. Some of these questions are nebulous and I'm left guessing about what you mean to be asking.

Some questions:

1. Are DRW F-350/3500 trucks "different" from DRW F-550/5500's because they're not on steel reinforced 19.5 pizza cutters? The two trucks are different - what exactly are you asking? I would forget about the DRW 350s - just as much hassle from this perspective w/o any of the benefits.
2. Can you get smaller, non-military super singles? For example, Earth Cruiser's run Toyo 37's, but start their life as a DRW Isuzu NPR. Yes. TrailReady (and others, I'm sure) will custom make you a set that would be compatible with either light truck (LT) beads (eg - Toyos) or military bead. The decision point is whether or not you want to use traditional LT or military tires.
3. Are their super single conversions that aren't $20k? Could you clarify what you think goes into a $20k conversion? A set of 5 custom super singles are probably $5-6k depending on where you go. Suspension mods increase the cost of related truck upgrades, but aren't necessarily mandatory to run super singles. Tires will add an additional $3-5k depending upon which ones you use. In practical terms, no one is going to just do singles and not adjust the suspension in some meaningful (and expensive) way. If you consider the super single conversion as part of the suspension upgrade recipe, then $20k seems reasonable.
4. Can you drive DRW trucks on the beach?
5. Are DRW vehicles harder to fit in a parking spot? NO.

Don't forget that super singles look way cooler.

DRW trucks obviously serve a practical purpose and are the best solution for the money to carry heavy loads - otherwise, they would not be the default solution on so many vehicles. Super singles are a legitimate improvement in specific use cases but I think you need to suss out what that is for you, first. Based on your numerous posts, it seems like a DRW setup would be fine 90% of the time.

 

[Peter_n_Margaret]

All 4WD vehicles that are designed as "serious" 4WDs from the ground up are super singles as designed and built. They don't generally have DRW versions of the same vehicles.
That applies whether it be a Haflinger or a Unimog.
The chassis width of a vehicle designed as a super single vehicle will generally be wider than a comparable DRV vehicle and this might be the cause of the stability difference that you mention.

Converting most "pretend" 4WDs to "serious" 4WDs will usually require much more than just super singles. Suspension is typically a more major task.
Cheers,
Peter
OKA196 motorhome (designed from the ground up as a "serious" 4WD with super singles).

 

[ReluctantTraveler]

All 4WD vehicles that are designed as "serious" 4WDs from the ground up are super singles as designed and built. They don't generally have DRW versions of the same vehicles.
That applies whether it be a Haflinger or a Unimog.
The chassis width of a vehicle designed as a super single vehicle will generally be wider than a comparable DRV vehicle and this might be the cause of the stability difference that you mention.

Converting most "pretend" 4WDs to "serious" 4WDs will usually require much more than just super singles. Suspension is typically a more major task.
Cheers,
Peter
OKA196 motorhome (designed from the ground up as a "serious" 4WD with super singles).

Here in the US, 4WD DRW trucks (from the factory, not conversions) are quite common.

 

[DirtWhiskey]

The main drawback for DRW on a 450/4500 or 550/5500 is tire size selection and lack of ability to air down, which is a big deal if you go into the back country. The reason most go to the bigger truck vs a 350/3500 is load capacity and, more importantly for me, the waaaaaaay better turning radius. Suspension mods are needed to do SS. Usually at least a 1.5" to 2" lift or level at a minimum and some trimming to make room for the meats. About to SS my 2nd F450, this one for more work than play.

1st round on my camper I went Buckstop and MPT81s. I needed the weight capacity of the military tires because of my big camper on it. This round I'm looking at 1st Attack and Micky Thompson 37s. Mostly because I don't need the massive weight rating on the work truck but also because there are 37s with siping for snow. Pretty sure there 335s with siping too but those tires are huge and hard to balance. Eventually I'll be derating the rears with custom arched springs to decrease bounce and allow more flex. None of this is cheap. I'm hoping to pull all this off for less than 10k for small lift (and all the things you need: springs or spacers, adjustable track bar or drop bracket, shocks, bumpstops etc), trimming, wheels and tires.

 

[ReluctantTraveler]

It would help if you distilled your questions down to specfically what you're wondering about. Some of these questions are nebulous and I'm left guessing about what you mean to be asking.

Some questions:

1. Are DRW F-350/3500 trucks "different" from DRW F-550/5500's because they're not on steel reinforced 19.5 pizza cutters? The two trucks are different - what exactly are you asking? I would forget about the DRW 350s - just as much hassle from this perspective w/o any of the benefits.
2. Can you get smaller, non-military super singles? For example, Earth Cruiser's run Toyo 37's, but start their life as a DRW Isuzu NPR. Yes. TrailReady (and others, I'm sure) will custom make you a set that would be compatible with either light truck (LT) beads (eg - Toyos) or military bead. The decision point is whether or not you want to use traditional LT or military tires.
3. Are their super single conversions that aren't $20k? Could you clarify what you think goes into a $20k conversion? A set of 5 custom super singles are probably $5-6k depending on where you go. Suspension mods increase the cost of related truck upgrades, but aren't necessarily mandatory to run super singles. Tires will add an additional $3-5k depending upon which ones you use. In practical terms, no one is going to just do singles and not adjust the suspension in some meaningful (and expensive) way. If you consider the super single conversion as part of the suspension upgrade recipe, then $20k seems reasonable.
4. Can you drive DRW trucks on the beach?
5. Are DRW vehicles harder to fit in a parking spot? NO.

Don't forget that super singles look way cooler.

DRW trucks obviously serve a practical purpose and are the best solution for the money to carry heavy loads - otherwise, they would not be the default solution on so many vehicles. Super singles are a legitimate improvement in specific use cases but I think you need to suss out what that is for you, first. Based on your numerous posts, it seems like a DRW setup would be fine 90% of the time.

Regarding the 3500 vs. 5500 question: one of the biggest complaints I hear about 5500 trucks is that the steel reinforced 19.5" wheels ride rough, don't soften even if you do air them down, and offer a limited selection of tire choices.

From what I can tell, the 3500 trucks run a different, softer tire that may ride better and offer more selection.

What isn't clear to me is if that's true or just me inferring incorrectly, and whether or not they have any capacity for being aired down that the 19.5's don't (or if because of concerns about rubbing it doesn't really matter either way).

"Super singles look way cooler" is subjective. I personally agree, but it's not how I'd make a buying decision about this.
The $20k conversion number is the one I see plastered all over the web in articles, videos, and such.

Maybe that's just the Buckstop Conversions price, but as someone who'd be doing none of the work myself, that's what I'm trying to understand. Asking "what I think goes into it" isn't a particularly useful question, because, frankly, I have no idea! I'm just quoting the number I always see.

Thanks for the info on military/non-military tires. Since these conversions seem to always go with the 41" military tires, I wasn't sure if they were the only ones that could handle the weight or something.

 

[Howard70]

Lots of reasonable advice so far. For us the primary issue with DRW is the lack of being able to air down for off pavement driving. While reducing tire pressure certainly helps traction the main advantage for us is ride quality on miles and miles of corrugated (washboard) and/or rocky tracks. We occasionally start off pavement at highway pressures thinking “it’s a short drive and the surface looks good” but that usually turns to “damn, this is a jarring track - let’s air down.”

Howard

 

[ReluctantTraveler]

The main drawback for DRW on a 450/4500 or 550/5500 is tire size selection and lack of ability to air down, which is a big deal if you go into the back country. The reason most go to the bigger truck vs a 350/3500 is load capacity and, more importantly for me, the waaaaaaay better turning radius. Suspension mods are needed to do SS. Usually at least a 1.5" to 2" lift or level at a minimum and some trimming to make room for the meats. About to SS my 2nd F450, this one for more work than play.

1st round on my camper I went Buckstop and MPT81s. I needed the weight capacity of the military tires because of my big camper on it. This round I'm looking at 1st Attack and Micky Thompson 37s. Mostly because I don't need the massive weight rating on the work truck but also because there are 37s with siping for snow. Pretty sure there 335s with siping too but those tires are huge and hard to balance. Eventually I'll be derating the rears with custom arched springs to decrease bounce and allow more flex. None of this is cheap. I'm hoping to pull all this off for less than 10k for small lift (and all the things you need: springs or spacers, adjustable track bar or drop bracket, shocks, bumpstops etc), trimming, wheels and tires.

This was a phenomenally useful response, thank you!

Reading between the lines, 350/3500's have a better tire selection because they're a different size than the 19.5"s on the 450/4500+, right?

(I totally get that the turning radius is way better on the bigger trucks because of the wider track, though.)

 

[ReluctantTraveler]

Lots of reasonable advice so far. For us the primary issue with DRW is the lack of being able to air down for off pavement driving. While reducing tire pressure certainly helps traction the main advantage for us is ride quality on miles and miles of corrugated (washboard) and/or rocky tracks. We occasionally start off pavement at highway pressures thinking “it’s a short drive and the surface looks good” but that usually turns to “damn, this is a jarring track - let’s air down.”

Howard

That's really useful to know!

Do other suspension mods—better shocks, or an air or liquid ride system—provide similar benefits? I realize a Kelderman or Liquid Spring setup is absurd expensive, of course!

 

[andy_b]

Regarding the 3500 vs. 5500 question: one of the biggest complaints I hear about 5500 trucks is that the steel reinforced 19.5" wheels ride rough, don't soften even if you do air them down, and offer a limited selection of tire choices.

From what I can tell, the 3500 trucks run a different, softer tire that may ride better and offer more selection.

What isn't clear to me is if that's true or just me inferring incorrectly, and whether or not they have any capacity for being aired down that the 19.5's don't (or if because of concerns about rubbing it doesn't really matter either way).

"Super singles look way cooler" is subjective. I personally agree, but it's not how I'd make a buying decision about this.
The $20k conversion number is the one I see plastered all over the web in articles, videos, and such.

Maybe that's just the Buckstop Conversions price, but as someone who'd be doing none of the work myself, that's what I'm trying to understand. Asking "what I think goes into it" isn't a particularly useful question, because, frankly, I have no idea! I'm just quoting the number I always see.

Thanks for the info on military/non-military tires. Since these conversions seem to always go with the 41" military tires, I wasn't sure if they were the only ones that could handle the weight or something.

19.5" tires can't be aired down due to their bead profile. Car and light truck tires use the interface between the wheel and bead plus the pressure within to hold the tires on. 19.5s and similar medium duty truck tires use air pressure to hold the tire one which limits how low you can lower the PSI to improve ride. This is why most people convert duals to military singles - the ability to lower PSI while maintaining an appropriate weight rating.

If subjective opinions of appearance or preference don't play a role in your decisions, kudos to you, but I think you're lying

I think you should know what you "think goes into it" so that when whoever does the work for you says this is "what goes into it," you're able to make an informed decision about it. For example, the Buckstop kit includes their bumpers to accommodate the wider track of the singles. Personally, I find these aesthetically challenging and would want to source something different.

As @DirtWhiskey pointed out, to make 41" MPTs fit, you'll need a lift. To make 37" Toyos fit on a 550/5500, you won't. You need to figure out what you're doing with your project - this will help you understand how heavy you're going to be. Once you have that estimate, then you can work out of this project would work on LT-type tires that come in smaller size. LT-type tires will probably limit you to around 14-15k GVWR but maybe that would be enough.

Suspension mods help a ton off-road, but adjusting your PSI probably makes the biggest difference for dollar invested. Suspension packages like the Kelderman and Liquid Spring add additional performance by creating multilink rear suspensions which provide better ride through better axle control and allowing the springs (air or liquid) to just do suspension work than older leaf-spring styles that use the spring pack as both a spring and to locate the axle as the suspension moves. You can definitely also create a multilink leaf-sprung rear fwiw.

 

[ReluctantTraveler]

If subjective opinions of appearance or preference don't play a role in your decisions

Oh of course they do! But for something like hauling a truck camper, I'm a lot more concerned with cost and function than "does it look cool." I'm also not someone who finds "having a bad** looking truck" appealing (just not my vibe).

I think you should know what you "think goes into it" so that when whoever does the work for you says this is "what goes into it," you're able to make an informed decision about it.

I agree! I'm here asking questions, right?

You need to figure out what you're doing with your project

For sure, and thanks for all of the additional info!

I don't see this is a linear process. Understanding the tradeoffs of 350/3500 trucks vs. 550/5500 trucks, DRW vs. super singles, and so on all help inform the design decisions.

As an example, I'd LIKE to be able to do some beach camping.

There are a few ways we could get there...

1. Lighter camper running on an SRW 350/3500.
2. Bigger truck converted to super singles that can be aired down.
3. Maybe a smaller DRW with tires that can be aired down a little?

That's not the ONLY criteria, of course. There's no perfect setup, it's all about compromises.

My point is that it's easy to say "figure out what you want to do, then pick the truck," but understanding what those tradeoffs are is part of the process (for me, anyways). Which is, again, why I'm here asking questions.

 

[simple]

On my F450 running duals with new tires and new shocks, I couldn't get it to ride comfortably on the highway. The new rear tires were close to $2000 at Les Schwab. I had them try machine balancing, balancing beads, polishing the interface between the rim and hub, demounting / remounting. I eventually had their guy go for a ride with me and he said that the vibration was minimal and normal for that type of heavy duty truck. I've read other people reporting the same experience and then found super singles to be an improvement.

I had an 01 Ram 3500 dual rear and it was smooth and quiet on the highway. I didn't like the duals on that due to reduced fuel economy, tire cost and all the other reasons mentioned. It was night and day more stable and secure feeling with a camper compared with the 4 other Ram 2500's that I had.

I mentioned in one of your other threads that my next build will be a 3500 single rear wheel with the lightest flatbed composite camper build I can do.

 

[ReluctantTraveler]

On my F450 running duals with new tires and new shocks, I couldn't get it to ride comfortably on the highway. The new rear tires were close to $2000 at Les Schwab. I had them try machine balancing, balancing beads, polishing the interface between the rim and hub, demounting / remounting. I eventually had their guy go for a ride with me and he said that the vibration was minimal and normal for that type of heavy duty truck. I've read other people reporting the same experience and then found super singles to be an improvement.

I had an 01 Ram 3500 dual rear and it was smooth and quiet on the highway. I didn't like the duals on that due to reduced fuel economy, tire cost and all the other reasons mentioned. It was night and day more stable and secure feeling with a camper compared with the 4 other Ram 2500's that I had.

I mentioned in one of your other threads that my next build will be a 3500 single rear wheel with the lightest flatbed composite camper build I can do.

My dude, thank you!

here's a lot of push on this forum to "just get the bigger truck" because of the wider track and better turn radius, so I appreciate you commenting on the comparable ride quality.

I'd gone down the 3500 SRW (stock, not super single) analysis path, and I think I'm going to be just too close to the max payload to make it work comfortably

What kind of driving were you able to do in the 3500 DRW? Did you feel like there were places you couldn't take it?

 

[deserteagle56]

Just some advice from someone who has been using a heavy cabover camper on a truck for many years...you will have to restrict yourself to "good" dirt roads only. A hundred miles of the vibration caused by a washboardy dirt road will cause serious damage to most campers...literally shake it apart unless you drive very, very slowly. They are not designed to take that kind of abuse. An uneven road surface (that puts the truck in a twist) can tear the camper apart unless you have it mounted on a 3-point system to allow for the flex in the truck bed.

I started out with a cabover on a SRW truck. Any off-camber situations (camper on truck is nearly 13' high) were terrifying; powerful wind gusts from the side induced a high pucker factor also. So I went to a dually. For roads good enough to take a truck/cabover camper on, the dually has worked out very well. And, as many years as I've been driving the below setup, I've never had a rock caught between the duals.

 

[StenchRV]

That's really useful to know!

Do other suspension mods—better shocks, or an air or liquid ride system—provide similar benefits? I realize a Kelderman or Liquid Spring setup is absurd expensive, of course!

YES!

Like Howard70 implied.

We usually air down the tires first, it GREATLY improves the ride and aides in not beating the heck out of the habitat and truck.
Then if we take just a few pounds off the highway airbag pressure setting in the Kelderman set up on our rig it lets the suspension move a little easier and do its "thing" . HUGE difference doing just those 2 things. I am almost ready to bolt on 4 custom ADS shocks sitting on the bench in my shop. You can upgrade a little at a time to help spread out the BIG $$ spending .

I agree with most people, the $20K number for Super Singles is WITH some suspension modifications. CAN you spend $20K on just wheel and tires...sure but no reason to. You will likely do some suspension mods even with DRW's, and you will likely purchase better tires if you decide to stay DRW. My stock tires were great during the build, but they were designed for commercial use NOT for off the beaten path travel.

CHEERS!!