put my 19.5s on today

jimh425 wrote:
At this point, 19.5s aren't about theory. They've been in use here in the truck camper forum since before I got here. I'd say a conservative guess is 10 years.

I and others have noticed that tire failure is by far the most common one, but also, the most scary failure. No, not frames, not axles, not brakes, not springs .... nope, tires! No, I'm not saying tires on SRWs. Tires generally are what fails on DRWs as well with a significant number of the failures being fronts! It's one of the reasons that I went with a DRW with 19.5s. I wanted a stronger tire.

If you don't believe me, research your theory here. Or, continue to make up a theory on what is by far the biggest improvement people can make to improve their rigs reliability to carry a Truck Camper.

Maybe the posts from some on this thread is about the troll ... if so, great job! ;)

If I read this right (not disputing just clarifying) you say that the rears on DRW trucks fail more, is that because you think folks overload because they think they can because they have duals and these tires are LT type?

I didn't have a failure...why I moved was because I was really unhappy with the milage of the LT tires (less then 45K and the cost and no gain with a supposed better tire costing more) and the rolly ride (stability). All the rest of the advantages of 19.5's then just added to my original thinking. It has worked for me and so far I will be on the plus side $wise when it comes time to replace. And you cannot place a price on the peace of mind...plus I like folks asking me about the rig and tires..it is fun!!! :>)

I believe the biggest reason 19.5" wheels are not sold on SRW trucks is vehicle comfort followed by reduced speed ratings. The majority of SRW owners use the pickup as a secondary or primary vehicle unloaded which puts too many limitations on the owners that haul infrequently. Those that need more weight carrying still have the option of going to a DRW with LT tires that do not hamper ride or restrict speed like the commercial tires.

My front Dana 60 axle is typically loaded 4500-5000 lbs and my rear Sterling 10.5" axle is typically loaded 7000-8000 lbs. I am a good example of someone that benefits from a 19.5" SRW or LT DRW pickup. You could argue that I should be driving a dually, but show me a dually that is under 20' long in my cab/bed configuration that is not a custom build...

I do realize there are limits to my configuration and we plan to up size truck, camper and trailer starting in the near future. As I upgraded in the past, this will happen with the weakest/smallest component getting replaced and subsequent upgrades happening as funds allow. Luck does play a factor in the research or method I am following.

twodownzero -

Some corrections to your posts you have made:

1. Class 2 and 3 trucks are very similar in build between each other and can even be ordered in down rated GVWR to allow less expensive commercial licensing cost even though they are identical trucks to the higher rated ones. The F450 pickup is actually a beefed up version of the F350 and can also lumped into this group. Many parts are identical or interchangeable in these two classes and you even order a Class 2 truck that has higher ratings than the Class 3 if you choose your options carefully.

2. Class 4 and 5 trucks are chassis cabs which share body and some power trains with the lower class pickup trucks. Much less of the chassis, suspension and axles cross between the pickup and chassis cab lines. Between Class 4 and 5 trucks much of the parts are interchangeable like they are between Class 2 and 3.

3. The chassis cab models are not limited to 4.88 gearing. Gas engines can have 4.30 or 4.44 gearing while diesels are also offered in 4.10. Although power trains are similar to Class 2 and 3 pickups, they are detuned to be able run at maximum output of longer duty cycles at heavier loads than the lighter pickups.

At this point, 19.5s aren't about theory. They've been in use here in the truck camper forum since before I got here. I'd say a conservative guess is 10 years.

I and others have noticed that tire failure is by far the most common one, but also, the most scary failure. No, not frames, not axles, not brakes, not springs .... nope, tires! No, I'm not saying tires on SRWs. Tires generally are what fails on DRWs as well with a significant number of the failures being fronts! It's one of the reasons that I went with a DRW with 19.5s. I wanted a stronger tire.

If you don't believe me, research your theory here. Or, continue to make up a theory on what is by far the biggest improvement people can make to improve their rigs reliability to carry a Truck Camper.

Maybe the posts from some on this thread is about the troll ... if so, great job! ;)

jimh425 wrote:

twodownzero wrote:
I agree that truck camper people tend to push their luck--many far beyond what I would do. Those people, especially, ought to have 19.5 on their 1 ton trucks.

I suspect people are adding 19.5s to NOT push their luck. I know I did on my SRW. Stock worked. Modified made it better.

DRWs can be overloaded, too. There are many examples here if you look. But let's not forget those who are over by what they carry or what they tow or simply by not using enough air pressure.

X2

WOW!!! I knew my 2004 TCD surrounded by a Dodge was a pretty good truck...now I know even more and it seems to be better than I think it is. BUT here's the good part...I don't want it can do any more than it is doing. My tires if anything make me feel much better running down the road.

Now here is a funny one for you. My boat trialer has a single axel and 14" tires...I was looking at trailers the other day at a boat dealer and noticed that two trailers looked exactly the same but had diff load ratings...I asked the dealer what's up with that...he said you are right the frames, rollers, bracing, cross memebrs, hitch, surge brake, disc brakes are all the same...it is the wheels and tires and the fender to cover them...so to increase the relative safety of my trailer, I'd need to change to 15" wheels and tires and higher load range which comes with the increase in size...I know not always...but in this case it does...oh yeah my fenders will not work either without changing the support bracket. So as far as I am concerned the tires on my truck do what I need them to do!!! And the trailer tire are monitored at every stop, yes I have a spare unlike so many out there...may boat trailer with boat made a trip to FL and back racking up over 8000 miles. I rolled along at 65 to 75 for many many miles. But I pay attention to my rig, like I think many TCer's do.

It is amazing where this thread went from a simple happy anouncement and a succesful trip with his new wheels and tires...Buzz see what you did! HEHE!!

I enjoy my truck and I know you do too. Isn't that what it is all about!!

twodownzero wrote:


Yep, but not on trucks that come with 19.5s from the factory. As far as I know, ALL of them come with larger rear axles than 1 tons do.

So now we are comparing SRW's with 19.5's to 4500/450+ chassis trucks?

I thought this discussion was about 2500's and 3500 SRW's with 19.5's compared to 3500 DRW's?

twodownzero wrote:
But they're not identical. Because they are located on a truck that has a different stance. A truck is not merely the sum of its parts.

They are the same axle, the AAM 11.5" axle. There are 2 differences that have nothing to do with rating. The WMS-WMS is different on the DRW to put the WMS between the duals, and the outer bearing is larger to support the added weight of a DRW setup. Per AAM, I have spoken with their engineers, SRW or DRW has no effect on the rating or capabilities of the axle. Dodge already spec's a longer life bearing than GM, so that's a plus for the Dodge guys.

A truck is the sum of it's parts, down to the weakest link. Dana 80's on a Ford Ranger is still Ranger and the weakest link will be frame/suspension. It's parts don't all add up, but we aren't talking about a Ranger.

The parts you listed above that will wear out or be possibly overloaded by adding, and utilizing, 19.5's just isn't an issue, those same parts in the same configuration are already used at a higher rating.

The stance on a DRW is wider, but the sidewalls on LRE's are softer so it's a trade off. It's not a 100% solution, but I would guess a 90% solution. The springs still mount at the same point, meaning any pivoting differences are tire related. I know from experience that SRW 19.5's are just as stable as a DRW, from the drivers seat.

twodownzero wrote:
Over what GVWR? No doubt the DRW GVWR has its most significant connection to the two additional wheels and tires, but once again, a truck is not merely the sum of its parts

Again, nearly all the same parts.

twodownzero wrote:
Engineering does not depend on public perception. Marketing might.

Does marketing not drive engineering?

twodownzero wrote:
A V8 diesel has advantages in a pickup that don't exist in an OTR rig. The first is weight. A V8 has a shorter block with fewer main bearings and other heavy components. I don't have the numbers off the top of my head, but it seems intuitive that an engine that is smaller will weigh less.

Both the 6.7L V-8 powerstroke and the 6.7L I-6 Cummins weight ±1100lbs. The powerstroke has 5 main bearings for 8 cylinders and aluminum heads, the Cummins has 7 main bearings for 6 cylinders and a cast iron head.

Cubic inch per cubic inch a V-8 is not lighter, and if the powerstroke has cast iron heads it would be even heavier.

twodownzero wrote:
But don't make the mistake of believing that installing Class 4 or 5 tires makes a pickup into a Class 4 or 5 truck. It doesn't. It just makes an overloaded pickup minus its weakest components.

Where is anyone trying to make a SRW a Class 4 or 5 truck? I guess it goes back to my first comment.. I though we where all discussing 2500 or 3500 SRW vs 3500 DRW and the capabilities/safety/design specs of 4x19.5's and 6xLRE's.

If the trucks are built the same, aside from the mentioned rear suspension differences, and the rear suspension is addressed then the difference is wheels/tires... and those are just 32 lug nuts away from being capable.

Upgrading the tires on most 3500 DRW wheels is pointless anyhow, the wheels are rated lower than the OEM tires.. at least on the wheels I have looked at. It's not merely the tires, the wheels mean a lot too.

Lets look at your overloaded logic real quick. Here is my truck on one of my recent trips.

FAW 4780 FAWR 5200
RAW 7160 RAWR 6200 sticker, 9350 highest for suspension/axle/frame, 10912 manufacturer
GVW 11980 GVWR 9900 sticker, 12,200 highest for frame/suspension/axles

Is that overloaded?? No, not in the least. Even if you factor in the main leafs are rated for 7% less on my SRW than a DRW of the same year there isn't anything overloaded.

Yeah, this is where you would mention the sum of the components.. but if the sum of components is good enough for a DRW at those weights why not a SRW? Tire's isn't it, those are rated for 9,000lbs an axle. I won't put 9,000lbs on my front axle as it's rating is not based on tires, but I wouldn't hesitate to do it on my rear axle where nothing is overloaded, thou components may be loaded to capacity.

Yes plenty of people overload their trucks, on HD SRW's it's almost always tires on the rear axle as anything is very hard to overload. On DRW's it's usually GVW as many ignore GVW and use FAW/RAW alone. On LD trucks it's usually everything :-)

Application and correlation.

Based on your logic if I owned a 2500 vs of my truck that scaled at 9500lbs I should sell it for a 3500 SRW of the same year as it carries a GVWR that supports 9500 lbs despite the fact that both trucks are supporting the weight identically, with identical components, at 9500lbs. The only difference is the upper overloads, which don't do anything at a weight that light. Is that logical, or missing correlation?

If that's your stance with your money then so be it, many people are that way. But to come and tell people it's wrong isn't really accurate either. It's not illegal, nothing is actually overloaded, and it's not any less safe.

twodownzero wrote:
Those of you with campers that are technically too heavy for any light duty truck have no choice but to either band-aid a pickup into handling the load or buy a Class 4 or 5 truck. I don't blame you for putting 19.5s on a 1 ton and rolling on, since that gets you the gearing for the highway, components that are probably capable of handling the load anyway, and tires and wheels that will certainly handle the load. But don't make the mistake of believing that installing Class 4 or 5 tires makes a pickup into a Class 4 or 5 truck. It doesn't. It just makes an overloaded pickup minus its weakest components.

I like this guy a lot.

Hopefully twodownzero will weigh in when we have our monthly visit by someone that wants to put a 4,500 lb Truck Camper, that they just bought off of Craig’s List, to fit on their ¾ Ton Chevy PU. “Will This Work?” or “I know some of you do it, tell me how to make my ¾ Ton Ford Truck a 1 Ton truck, cheap!”

b

pjay9 wrote:
don't they use the same axel on different models...cost economy of manufacturing sort of thing!

Yep, but not on trucks that come with 19.5s from the factory. As far as I know, ALL of them come with larger rear axles than 1 tons do.

AH64ID wrote:

Aside from tires do you the know the only difference between my SRW and a DRW of the same year? The main leaf pack of the DRW is rated 7% higher, that's it! Everything else you listed is identical. Ford and GM do similar things.

But they're not identical. Because they are located on a truck that has a different stance. A truck is not merely the sum of its parts.

Why do is everything a DRW and not a super single SRW? There is a minor benefit to the width, but one is generally above GVWR at that point.

Over what GVWR? No doubt the DRW GVWR has its most significant connection to the two additional wheels and tires, but once again, a truck is not merely the sum of its parts

There is also public perception, same reason the all new powerstroke was made a V-8 when OTR trucks have shown us an I6 is better.

Engineering does not depend on public perception. Marketing might.

A V8 diesel has advantages in a pickup that don't exist in an OTR rig. The first is weight. A V8 has a shorter block with fewer main bearings and other heavy components. I don't have the numbers off the top of my head, but it seems intuitive that an engine that is smaller will weigh less.

The second is displacement, and more specifically, stroke. V8 diesels have wider powerbands than I6s when used in this application. That's one thing I noticed immediately when comparing the trucks when I was shopping--the Cummins has a far narrower powerband than the Ford or Chevy.

Which is "better" for a particular application is complex and not a simple answer. An I6 is probably better for OTR because there is plenty of room, the weight doesn't really matter, and the increased number of bearings makes for less stress over the long life of an OTR truck. Many of these factors are different in a pickup, which has a much shorter useful life and can benefit much more from a lighter weight engine.

As with all engineering problems, cylinder configuration is a tradeoff, not a slam dunk.

Tire cost is another, as well as ride. My 19.5's ride petty good compared to my LRE's, in fact I prefer the ride in most conditions, but they are not what most people want from a ride. They also carry a 75 mph speed rating, lower than the rural interstate speed limit out here.

And with 3.55, 3.73, or 4.30 gears, that could be an issue. On a Class 4 or 5 truck that comes with 4.88s, it isn't as much of an issue. Either way, a non-commercial truck with a 75 mph speed rating probably isn't something that the NHTSA would be too fond of.

...

You can see there isn't a lot of difference, and certainly nothing a pair of airbags can't handle for a SRW.

By that logic, there would be no meaningful difference between my own truck with 19.5s on it and a DRW truck with E rated tires. The comparison is also apples to oranges, because no DRW 1 ton--nor any 1 ton for that matter--comes with 19.5" tires.

I have not argued that airbags and heavier duty tires don't make a difference--they clearly do and I have them on my own truck. But to suggest that even if the frames, springs, overloads, etc. were identical, that a DRW isn't safer with a heavier load than an SRW--even an SRW with tires that aren't overloaded--is to once again miss a key point: a truck is not merely the sum of its parts.

It should not go unnoticed that NO light truck comes with 19.5s, and the trucks that do come with 19.5s use heavier rear axles than a 1 ton truck.

Perhaps ideally, the manufacturers would start making Class 4 and 5 trucks with 3.55 or 3.73 gears so that they were capable of carrying a heavy load but yet not designed for pulling so much. A Ram 5500 loaded at 15k lbs GVW doesn't need 4.88 gears. Along with the heavier duty wheels and tires, you'd get the suspension and rear axle designed for the GVWR necessary for the heaviest campers.

Me personally, I'd still rather have a 1 ton for my use, for ground clearance and for traction since E rated tires are softer and grippier in general than that which is available in 19.5 sizes. But the reason I say that is that my camper is light enough that I can stay within a 1 ton's GVWR if absolutely necessary.

Those of you with campers that are technically too heavy for any light duty truck have no choice but to either band-aid a pickup into handling the load or buy a Class 4 or 5 truck. I don't blame you for putting 19.5s on a 1 ton and rolling on, since that gets you the gearing for the highway, components that are probably capable of handling the load anyway, and tires and wheels that will certainly handle the load. But don't make the mistake of believing that installing Class 4 or 5 tires makes a pickup into a Class 4 or 5 truck. It doesn't. It just makes an overloaded pickup minus its weakest components.

Great post. Had to explain to other members the same in regarding 03 to 09 Dodges ram 2500/3500 are the same except for top overload spring and sway bar.