What is the best setup for hauling 5th wheel campers ?

[NIsaacs]

Opps, my bad again:-laf

Nick

 

[NIsaacs]

Here's a shot of the 17.5"s Gatormade uses, they look a touch different from your dump.

View attachment 101569

That being said I'm on my phone this morning so can't get a good close up of Greg's picture. So you could very well be right... again

Note the marker/signal light with the support plate, that is a good idea but not the spliced rub rail at that location. My sons Big Tex has a slight bow right in the light on his side rails. A surface mount would be better, here. Not nit picking Gatormade..... well maybe I did

Nick

 

[SnoKing]

Sounds like the majority of you guys already have this axle ratio thing figured out.
I guess I can add my lackluster 3.73’s to the list of other things most worry about....capless fill, DEF (whether box or bulk), water pumps, and partial fluid changes. I feel it is indeed truly a miracle my truck has made it to 338K.....especially with these LT235/80R17 Bridgestone RD 500 HD tires that have miraculously made it 130K miles.

And again I ask, at what speed and gear do you normally tow in? To really understand this 3.73 ratio, your input of speed and gear would be helpful.

And yes the RD-500 HD is a long wearing tire. I put a LT265/75R16E set on my old 2001.5 RAM a couple years before selling it. Had to be pretty careful when roads were wet, as they hard limited traction with here extremely hard rubber compound. Guy that installed them questioned why I was pulling a commercial grade tire on the truck. They would me a great trailer tire!

 

[Cummins12V98]

On page three I posted this hoping GS would have responded to it.

"I was waiting for you to reply. What weight range do you haul combined?

Honest question give an honest answer. If your combined load would never exceed 29k would you get the 3.42's? If not give a reason why not."

 

[kthaxton]

Have you every had a beer with him, or worked on trucks together? I didn't think so!!!!

If I did, would that make him right?

Have you every owned a RAM with a Aisin transmission?

No, but I know the principles of gear reduction and have experienced those differences in other vehicles, there are no unique physics that apply only to an Aisin. In fact, where I get mostly concerned about the R&P ratio is typically in the upper gears of the trans, in which there is little ratio difference between an Aisin and a 68RFE. Again, y'all make it sound like there are only two functional RPM points to tow in, as if anything more or less is not functional.
"Compromise" does not mean all results are worse, it also means some are better.

It's stupidly simple:

3.73's will tow slightly better than 3.42, but not as good as 4.10. If one tows moderately heavy (but not the max mind you), 3.73's would perform better than 3.42's.
It's not ONLY about RPM either, even more importantly its about mechanical advantage (leverage). If you could somehow take the RPM equation out, there is still a torque multiplication that is going on.

annnnnnnnnd, a further benefit, the lower your R&P ratio is, the easier life is for every component in front of the pinion.

 

[dfb]

The question as I see it. The best tow rig in an 18 or 19 Ram truck.. this was answered. 3500 or better DUALLY, AISIN, 4:10..that's it period..You cannot have the best towing and fuel mileage, ain't gonna happen. I have had an 04 itch a six speed stick.. I just traded in a 2015 with the 3:42s. On flat ground pulling the Montana the trans would hunt between 5th and 6th.. So towed in 5th. Aisin trans. Pulling the same load with the new 4:10 truck the rpms at 60 in 6th gear is about 1800 rpms. The 3:42 truck in 6th was 1450.. Tow rating on 15 was 16750, compared to over 31000 with 4:10s.. I do think you may look into a chassis cab 4500 or 5500 and buy a hauler bed..Once again, dually, 4:10, aisin..

 

[SnoKing]

I little work with a gear cal shows that in 6th gear one would have to tow at 70 MPH to get the engine up to an acceptable 1750+/- RPM. Given 31.8 inch LT235/80R17 tires and Aisin.

In 5th gear at 65 MPH the engine would be turning 1975 +/- RPM with 3.73 gears.

Now replace the 3.73 with 3.42 and in 5th at 65 MPH engine would be turning a more acceptable 1809 RPM. And you have direct drive 4th available for hills at the same speed and lots of pulling power at 2350 RPMs.

3.73 in 4th gear would have the engine at 2562 at 65 MPH.

So speed that one wants to tow is in play here.

 

[SnoKing]

double post.

 

[SnoKing]

If I did, would that make him right?




No, but I know the principles of gear reduction and have experienced those differences in other vehicles, there are no unique physics that apply only to an Aisin. In fact, where I get mostly concerned about the R&P ratio is typically in the upper gears of the trans, in which there is little ratio difference between an Aisin and a 68RFE. Again, y'all make it sound like there are only two functional RPM points to tow in, as if anything more or less is not functional.
"Compromise" does not mean all results are worse, it also means some are better.

It's stupidly simple:

3.73's will tow slightly better than 3.42, but not as good as 4.10. If one tows moderately heavy (but not the max mind you), 3.73's would perform better than 3.42's.
It's not ONLY about RPM either, even more importantly its about mechanical advantage (leverage). If you could somehow take the RPM equation out, there is still a torque multiplication that is going on.

annnnnnnnnd, a further benefit, the lower your R&P ratio is, the easier life is for every component in front of the pinion.

Including the double overdrive ratio of .63???? vs the first OD ratio of .77??????

What do you tow and how fast?

 

[Cummins12V98]

I kept a record of minimum speeds at mile post markers with my 11 HO Dually 350/800 towing a combined 29k along Southern Oregon and Northern California with 3.42's on I-5. The 11 easily outpulled my current 15 DRW 385/865 with 4.10's at 33K combined.

So someone please explain that! YA 4K more weight but both RV's are wide body and over 13' tall. With the extra power and 4.10's I thought I would blow the 11 away, NOT.

So all this gear multiplication BS is just that.

 

[SnoKing]

I kept a record of minimum speeds at mile post markers with my 11 HO Dually 350/800 towing a combined 29k along Southern Oregon and Northern California with 3.42's on I-5. The 11 easily outpulled my current 15 DRW 385/865 with 4.10's at 33K combined.

So someone please explain that! YA 4K more weight but both RV's are wide body and over 13' tall. With the extra power and 4.10's I thought I would blow the 11 away, NOT.

So all this gear multiplication BS is just that.

The 15 pulls in .77 OD 5th gear vs the 11 pulling direct drive 4th gear?

 

[Cummins12V98]

I don't understand all the math involved never had a reason to know. But the nay sayers should take note to what I posted about how well the "inferior" system worked.

If the 11 had the AISIN I would most likely still be running the 11 even towing 35K combined at times.

 

[kthaxton]

Including the double overdrive ratio of .63???? vs the first OD ratio of .77??????

I'm not sure what your question is? Including what about the OD ratios?

What do you tow and how fast?

I have two pulling scenarios, 5th wheel by itself (pretty light, at about 10k loaded) and pulling doubles with a trailer/RZR behind, for a total around 12k (18k-20k Gross).

I have no set rule about how fast I tow, it depends on the road and which configuration I'm pulling. I usually tow at or near the speed limit, or slightly below (depending the road, especially with doubles). However, I do not go 80, where 80 is allowed.

 

[kthaxton]

So all this gear multiplication BS is just that.

It's physics! You can't argue it! Lower ratios multiply torque, it is an inarguable fact.

The only way to do a fair comparison is having two identical trucks, with two identical loads....with the two different ratios. Your comparison does not prove anything.

 

[Cummins12V98]

"Your comparison does not prove anything."

Sure it proves the 3.42's work quite well to pull a heavy load in 5th, 4th and 3rd. But you won't admit that.

 

[SnoKing]

OD ratios subtract from torque multiplication, right? That is it takes more engine power to turn a .77 OD vs a direct drive ratio and more yet for a .63 OD ratio to get the same power to the drive shaft. So as we debate diff gear ratios, we have to account for the transmission gear in use.

 

[kthaxton]

"Your comparison does not prove anything."

Sure it proves the 3.42's work quite well to pull a heavy load in 5th, 4th and 3rd. But you won't admit that.

You're not paying attention and you are trying to change the argument. 3.42's DO work quite well, I'm not arguing that. I have them. They are great for what I tow. However, If I towed a reasonable amount more, I would want 3.73....and they would be BETTER than (see that? better than) 3.42's.
It is a fact, lower gear ratios (numerically higher) multiply and provide more torque, you just need to balance that with engine RPM.

 

[kthaxton]

OD ratios subtract from torque multiplication, right? That is it takes more engine power to turn a .77 OD vs a direct drive ratio and more yet for a .63 OD ratio to get the same power to the drive shaft. So as we debate diff gear ratios, we have to account for the transmission gear in use.

Yes, I understand that, I am just trying to understand how you are applying that to the discussion....because the Aisin and the 68 have nearly identical OD ratios.

 

[kthaxton]

Sure it proves the 3.42's work quite well to pull a heavy load in 5th, 4th and 3rd. .

To be even more to the point......and 3.73's would pull that same load better in each of those respective gears....and make 6th more usable.

 

[SnoKing]

"There is always a gear reduction in the differential between your pinion and ring gear. This is not a variable gear ratio. The Final gear ratio is. Differential gear ratio x The Ratio Which You Select using your gear box lever."

So a 3.42 geared truck in 5th has a slightly lower final gear ratio than a 4.10 geared truck in 6th.

0.77 3.42 2.6334
0.63 4.1 2.583

Now move them to 4th in the 3.42 truck and 5th in the 4.10 geared truck.

1 3.42 3.42
0.77 4.1 3.157

And 3rd and 4th gear
1.34 3.42 4.5828
1 4.1 4.1

And 2nd and 3rd
2 3.42 6.84
1.34 4.1 5.494

And 1st and 2nd
3.75 3.42 12.825
2 4.1 8.2

For comparison, the 47RE with 4.10's in first gear.
2.45 4.1 10.045

These final two comparison shows why a 3.42 Aisin trannied truck can get a load moving.

Then there is 1st gear in a 4.10 Aisin truck at
3.75 4.1 15.375

Which Ron says it would be nice to lock out at times and start in second gear.

The 3.42 truck wins in 5 of the 6 gears in the comparison with slightly lower ratios. Add in the slightly shorter tires on the dually and they probably come even up.

All of that and the 3.42 has an excellent freeway cruise gear when not towing.

0.63 3.42 2.1546