AEV Prospector XL Flatbed Adventure Rig

[RAM5500 CAMPERTHING]

So what's the deal with gears on the new trucks? Everyone I've seen running a 21' is still on stock gears. Is nobody making a 4.10 or 4.30 conversion for them yet? Even AEV is spec'ing 3.73's with 40's.

I've never driven 40's with the stock 3.73 ratio, but my guess is that it leaves a lot to be desired?

Im going to guess it’s simply that people don’t know any better.

I ordered my Ram 5500 (with Cummins) with 4.89 gearing because I knew I’d be running 41”

It does pretty well and after dialing in the speedo the granny shifts perfectly.

With that being said, it could still be improved a little with a 5.something I bet.

The fact some people are running even higher hearing claiming it’s fine is nothing more than gibberish ?

My .02

 

[mog]

So what's the deal with gears on the new trucks? Everyone I've seen running a 21' is still on stock gears. Is nobody making a 4.10 or 4.30 conversion for them yet? Even AEV is spec'ing 3.73's with 40's.

Maybe I misunderstand, but sticking with Dodge (this thread's brand),
the Power Wagon comes stock with 4.10 gears and both the Laramie and Big Horn have 4.10s as a $145 option
From the Build a Ram website

Power Wagon

Laramie and Big Horn

And Nitro Gears sells everything up to a 5.13

FYI I run 42"s on my stock 5.13 gears, (C4500 Kodiak) and could even go numerically higher IMO.

Ignoring the yellow/green/blue bands as those are for a Jeep JL/JT with the Pentastar engine, you can still use the gearing/rpm/tire diameter ratio.
For example, the stock Dodge 2500 tires are 285/70r-17 so 33" in diameter. And if the stock ratios offered are 3.73 or 4.10, using the RPM as a 'reference number' that would be 2207-2426, so with 41" tires 4.88 to 5.13 would give the same results.

 

[Tex68w]

The 2019+ HD's have an 11.5" rear end found in the 68RFE 6-speed non HO Cummins is different from those before them. The trucks with the Aisin/HO Cummins have a 12" which can be ordered with lower gear sets. I haven't looked to see what the new AEV trucks are coming with but my guess is they are only Aisin trucks or they are simply putting them out there with 3.73's. You can get by on 37's with the 3.73's with the diesel but it better be a short term deal with 3.73's and 40's because you'd have an effective 3.05 gearing, that's mighty tall for any low end use or off-road.

 

[Willman]

View attachment 659498

What a cool rig! If this doesn't bring a smile to your face i don't know what would. Keep up the great work!

 

[RAM5500 CAMPERTHING]

The 2019+ HD's have an 11.5" rear end found in the 68RFE 6-speed non HO Cummins is different from those before them. The trucks with the Aisin/HO Cummins have a 12" which can be ordered with lower gear sets. I haven't looked to see what the new AEV trucks are coming with but my guess is they are only Aisin trucks or they are simply putting them out there with 3.73's. You can get by on 37's with the 3.73's with the diesel but it better be a short term deal with 3.73's and 40's because you'd have an effective 3.05 gearing, that's mighty tall for any low end use or off-road.

For a diesel, the Cummins sweet spot for optimum efficiency/power is 1700-1800 rpm.

With 4.89s and 41s and the Aisin AS69RC 6 speed, I’m right at 1750 at 65mph.

im guessing with 3.73s, they’re floating around 1200rpm or so at 65mph.

Less than ideal for everything really, especially if towing ??‍♂️

 

[Tex68w]

For a diesel, the Cummins sweet spot for optimum efficiency/power is 1700-1800 rpm.

With 4.89s and 41s and the Aisin AS69RC 6 speed, I’m right at 1750 at 65mph.

im guessing with 3.73s, they’re floating around 1200rpm or so at 65mph.
Less than ideal for everything really, especially if towing ??‍♂️

Agreed, it's not ideal. The good thing is that Nitro informed me today that they will be coming soon.

 

[RAM5500 CAMPERTHING]

Agreed, it's not ideal. The good thing is that Nitro informed me today that they will be coming soon.

Nice! I’m basically stuck with what I got as there is ZERO aftermarket support for the 2019+ 4500/5500s when it comes to gear ratios

 

[ttengineer]

For a diesel, the Cummins sweet spot for optimum efficiency/power is 1700-1800 rpm.

With 4.89s and 41s and the Aisin AS69RC 6 speed, I’m right at 1750 at 65mph.

im guessing with 3.73s, they’re floating around 1200rpm or so at 65mph.

Less than ideal for everything really, especially if towing

I’ve found the sweet spot is right at 2000rpm. Diesels unlike gas engines require a little more RPM depending on gearing and transmissions to be more efficient.

You’ll probably find that if you’re heading down the road at 60-80mph and you drop your truck out of overdrive into 5th gear to hit that 2000 rpm sweet spot your fuel economy will improve pretty aggressively. Like 15%. Granted if you’re on varying pavement it won’t help so much as it’s still an 8000lbs+ truck and doesn’t sprint up hills. Either way try it out. I think you may be impressed.


Sent from my iPhone using Tapatalk

 

[RAM5500 CAMPERTHING]

I’ve found the sweet spot is right at 2000rpm. Diesels unlike gas engines require a little more RPM depending on gearing and transmissions to be more efficient.

You’ll probably find that if you’re heading down the road at 60-80mph and you drop your truck out of overdrive into 5th gear to hit that 2000 rpm sweet spot your fuel economy will improve pretty aggressively. Like 15%. Granted if you’re on varying pavement it won’t help so much as it’s still an 8000lbs+ truck and doesn’t sprint up hills. Either way try it out. I think you may be impressed.

I will try this for sure and see what happens. As of now, fully loaded i am averaging 12.5mpg-ish, which i am super happy with.

But if the 2000k range is even better as you mention, that makes the claims of folks running 3.7whatever even crazier

 

[Tex68w]

Bone stock on 33's I am averaging 21mpg on the highway and 19mpg city and it's not even broken in yet. Obviously those numbers won't last once it's lifted but until stuff comes back in stock I'll be rolling stock lol. I expect 17-ish on 37's with the stock 3.73's and hopefully closer to 19-20 if I were to regear to 4.30's if/when those lower gear sets come available. I'd obviously go lower if I were to move up to 40's, barring gear set availability.

 

[RAM5500 CAMPERTHING]

Bone stock on 33's I am averaging 21mpg on the highway and 19mpg city and it's not even broken in yet. Obviously those numbers won't last once it's lifted but until stuff comes back in stock I'll be rolling stock lol. I expect 17-ish on 37's with the stock 3.73's and hopefully closer to 19-20 if I were to regear to 4.30's if/when those lower gear sets come available. I'd obviously go lower if I were to move up to 40's, barring gear set availability.

I’ve regeared one truck myself in my life and would NEVER do it again...

BUT... if you’re handy with a wrench and have some skill (or friend with some) most of the different gear ratios are actually available through the RAM dealer parts department.

Most shops won’t install gears they don’t sell, so send Install would probably be only option.

but it’s an option

 

[Tex68w]

Oh I'd definitely pay a competent shop to setup my R&P and I'll likely toss in an ARB Air Locker at the same time. Until Nitro or someone else comes out with lower gear sets for the 2019+ 11.5" trucks this is all just a dream lol.

 

[UglyViking]

Bone stock on 33's I am averaging 21mpg on the highway and 19mpg city and it's not even broken in yet. Obviously those numbers won't last once it's lifted but until stuff comes back in stock I'll be rolling stock lol. I expect 17-ish on 37's with the stock 3.73's and hopefully closer to 19-20 if I were to regear to 4.30's if/when those lower gear sets come available. I'd obviously go lower if I were to move up to 40's, barring gear set availability.

Take this for what it's worth but my dash tells me I get around 19-20 with summer fuel and mixed driving with a slight highway bias with Falken 37s. The dash has been updated to the actual wheel diameter measured. I've not done hand calculations yet but it's still got a surprising amount of pep stock, I expect it to get better tuned.

 

[Tex68w]

Take this for what it's worth but my dash tells me I get around 19-20 with summer fuel and mixed driving with a slight highway bias with Falken 37s. The dash has been updated to the actual wheel diameter measured. I've not done hand calculations yet but it's still got a surprising amount of pep stock, I expect it to get better tuned.

My buddy is tuned and deleted on his XL and with 40's he sees 18-20 mpg at 65-70 mph both on the computer (adjusted for gears and tire size) and when hand calculated. He says that he has seen 21-22 mpg on a short 50 mph stint once so I believe that you could definitely see those numbers or better with 37's and appropriate gearing.

 

[UglyViking]

My buddy is tuned and deleted on his XL and with 40's he sees 18-20 mpg at 65-70 mph both on the computer (adjusted for gears and tire size) and when hand calculated. He says that he has seen 21-22 mpg on a short 50 mph stint once so I believe that you could definitely see those numbers or better with 37's and appropriate gearing.

40s and over 10mpg is awesome. I bet it runs like a top too. Eager to see what you end up building out. I'm a little jealous of your 3500 payload but I'll make due. Don't want to hijack this awesome thread but looking forward to your build.