Ram 2500 XL for overland / expedition trips

[Ravenmad]

Those -18 wheels might be tough to fit without mucho trimming. Probably even so with the XL kit. The normal best fitment on Rams comes from +25 to +18 or so.

Hopefully they work. The AEV 17x10 that is used on the Prospector XL is a -15 (4.83 inch) backspacing wheel.

The wheel calculator I used sets the 9.5 inch wheel with more backspacing will sit about 1/8" shy of the 17x10 from AEV at the outside edge. Of course, I could be doing it wrong...

 

[Ravenmad]

This is the link to the wheel diameter / backspacing calculator. Its very easy...


http://marksink.com/tire_wheel_offset/offset.html

 

[RPhil]

Where did you source your wheels from? I am considering them as well.

 

[Ravenmad]

I have a good friend who owns a company and He allowed me to buy the wheels though his company at the distributors cost. Besides that, the best price I found was CARiD.

 

[Bayou Boy]

Gotcha. I thought the XL used the same rims as the normal Prospector. I didn't realize they had a totally different wheel.

 

[Explorerinil]

Just got off the phone with diesel power products and paid for some of the last parts I need.

Dynatrac Ball joints
Nitro Gear 4.88 gears and master install kit
ARB locker for the front
ARB Dual compressor
PSC full hydro assist steering system with AEV parts

4.30 gear were on the original menu as per AEV recommendation, however, after a conversation with Diesel Power Products I decided to go with 4.88s. The MPT 81 is just shy of a 41 inch tall tire, plus, the cummins wants to run between 18-2100 rpms when towing, so that puts me at 150 at 70 mph. Plus the tire is speed rated for 68 mph at max load (which I will never get close to).

I kept the rear factory limited slip that comes with the 4x4 offload package. IT is not positive like the ARB, however, for towing and cruising I think it will be fine. I won't be rock crawling with my truck and if I find myself in MOAB enjoying the scenery it will have to do.

I have a call into RCV about a set of 300M axles for the front to work with a dynatrac free spin kit, we will see what they say tomorrow hopefully.

Why do you need axles, you planing on bypassing the factory CAD with a one piece shaft?

 

[Ravenmad]

I am considering it, yes. since Dynatrac does not build a XD 60 or pro rock 80 front axle assembly for the RAM ..... lolol I really wish they did, it would make this easy...

Im thinking I will order a Carli truss for the front axle housing, bypass the CAD with one piece axle (RCV shafts) Dynatrac hub kit, dynatrac balljoints, ARB locker and help the front suspension with the lewis built radius arms.

I won't be racing the truck, nor will I be rock crawling it, however, it will weigh 10K when Im done, have 41 inch tires and 800lb of torque ...

 

[Ravenmad]

Gotcha. I thought the XL used the same rims as the normal Prospector. I didn't realize they had a totally different wheel.

yup. Looking back now, I probably should have just stuck with building a standard prospector clone... would have been cheeper and probably just fine for exploring and camping. I think its kinda like a jeep, you can run a 35 easily on a JK and really, its made to run a 35 with only minor issues to work through. However, as soon as you want to run 38s you have just opened up a whole can of worms that need to be addressed if you want the jeep to actually drive correctly and endure without repeated issues and failures.

I think a 37 on a RAM 2500 / 3500 is a fairly easy upgrade and only requires a few changes to make it good. It seems like 37s are the breaking point though and to move up from a 37 to a 40 reveals a lot of weak points that need to be addressed. Just my thoughts...

 

[Dalko43]

4.30 gear were on the original menu as per AEV recommendation, however, after a conversation with Diesel Power Products I decided to go with 4.88s. The MPT 81 is just shy of a 41 inch tall tire, plus, the cummins wants to run between 18-2100 rpms when towing, so that puts me at 150 at 70 mph. Plus the tire is speed rated for 68 mph at max load (which I will never get close to).

So could you expand on this bit? I've got a friend looking at bigger tires (35's) for his Ram w/ Aisin transmission. Stock gearing (for SRW) is 3.42. We've been debating back and forth on this. Some owners claim that 3.73's should be low enough to get the RPM back into OEM-like specs. Some even argue that stock gearing would work (I'm highly skeptical of those claims). Others say 4.10's or lower are needed.

What is AEV's mindset on gearing? Do they recommend going with gears that are low enough to get the RPM's back into OEM territory for highway cruising, or do they recommend going lower for accommodating increased weight and reduced aerodynamics?

 

[Ravenmad]

So could you expand on this bit? I've got a friend looking at bigger tires (35's) for his Ram w/ Aisin transmission. Stock gearing (for SRW) is 3.42. We've been debating back and forth on this. Some owners claim that 3.73's should be low enough to get the RPM back into OEM-like specs. Some even argue that stock gearing would work (I'm highly skeptical of those claims). Others say 4.10's or lower are needed.

What is AEV's mindset on gearing? Do they recommend going with gears that are low enough to get the RPM's back into OEM territory for highway cruising, or do they recommend going lower for accommodating increased weight and reduced aerodynamics?

Great question, I only know what I have been told by AEV and Diesel Power Products. AEV recommends 4.30 gears for 40 inch tires because thats the deepest gear ratio you can get in the AAM variety. DPP recommended 4.88 gears for 40s if your going to tow anything over 5k pounds. DPP thinking is based of off cummins power / efficiency range of 18-2100 rpm ( I guess its the sweet spot for the motor ).

As far as 35, crazy thing, I work with a guy who just bought a 15, 3500 with Aisin transmission. He has stock 3.42 gears and wants to run 35s, but he also tows a 10K toy hauler trailer. He purchased the truck just to tow his toy hauler on weekends. Seems like, if the truck is going to actually be used to tow heavy it would be in your best interest to use a rpm calculator to determine the best gear ratio to put the motor rpm at the bottom of the 18-2100 rpm mark for the speed you intend to drive. Could be 3:73s or 4.10s depending on the actual tire size and if you live in a state that sets 55mph as max or a state were you may drive 75mph while towing.

 

[Dalko43]

Great question, I only know what I have been told by AEV and Diesel Power Products. AEV recommends 4.30 gears for 40 inch tires because thats the deepest gear ratio you can get in the AAM variety. DPP recommended 4.88 gears for 40s if your going to tow anything over 5k pounds. DPP thinking is based of off cummins power / efficiency range of 18-2100 rpm ( I guess its the sweet spot for the motor ).

Ravenmad, did either of them (AEV or DPP) distinguish between the Cummins' optimal efficiency RPM range and its optimal work RPM range?

I've heard more than a few say that for best fuel efficiency, while empty, the RPM's should be around 1600-1700 RPM (the latter delivers peak torque). And I've heard others say that for best performance (towing, hauling) the RPM's should be between 1800-2100.

 

[ttengineer]

I'm pretty sure maxxis makes a 40x13.5R17.

Edit: they do.

https://www.maxxis.com/catalog/tire-5-105-creepy-crawler-m8090


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[ttengineer]

Great question, I only know what I have been told by AEV and Diesel Power Products. AEV recommends 4.30 gears for 40 inch tires because thats the deepest gear ratio you can get in the AAM variety. DPP recommended 4.88 gears for 40s if your going to tow anything over 5k pounds. DPP thinking is based of off cummins power / efficiency range of 18-2100 rpm ( I guess its the sweet spot for the motor ).

Ravenmad, did either of them (AEV or DPP) distinguish between the Cummins' optimal efficiency RPM range and its optimal work RPM range?

I've heard more than a few say that for best fuel efficiency, while empty, the RPM's should be around 1600-1700 RPM (the latter delivers peak torque). And I've heard others say that for best performance (towing, hauling) the RPM's should be between 1800-2100.

In my 3500 I've found, unloaded, my best fuel economy at 70mph is in 5th gear at 2000rpm getting 21mpg average.


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[Dalko43]

In my 3500 I've found, unloaded, my best fuel economy at 70mph is in 5th gear at 2000rpm getting 21mpg average.


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Which transmission do you have and how many gears?

 

[Boz]

Another tire option would be the Swamper Irok Radial. 39.5x13.5r17 is load range E with a 4080lbs rating. Could probably even fit the 41x14.5r17 which is D rated at 3850lbs.