Finally got it done, the most awesome thing Ive done to this truck. Say good bye to high egt's and hello to fuel mileage and power. She's a power house now.

 

 

What tire size are you running?

 

- John

On 10/11/2024 at 9:41 PM, jlwelding said:

Finally got it done, the most awesome thing Ive done to this truck. Say good bye to high egt's and hello to fuel mileage and power. She's a power house now.

 

Amazing how proper ratio really helps out. 

On 10/12/2024 at 9:17 AM, Tractorman said:

 

What tire size are you running?

 

- John

LT235-85-R16

On 10/12/2024 at 9:17 AM, Tractorman said:

 

What tire size are you running?

 

- John

235-85-R16

On 10/19/2024 at 7:05 PM, jlwelding said:

235-85-R16

 

I'll bet that is a powerhouse!

 

- John

235/85/16 = 31.7x9.3/16

245/75/16 = 30.5x9.6/16

265/75/16 = 31.6x10.4/16

 

You're pretty much in line with the 265/75/16, just an inch narrower tire.

 

What are your RPMs at 60 mph?

2k at 60 ,  egt's dropped 200 degrees. I was 800 degrees at 60-65. Now 600 - 625. I pulled 21k loaded with hay and it didn't faze it a bit. The hottest egt's got was a little over 1k, course the turbo helped a lot.

On 10/21/2024 at 4:11 PM, 01_Cummins_4x4 said:

235/85/16 = 31.7x9.3/16

245/75/16 = 30.5x9.6/16

265/75/16 = 31.6x10.4/16

 

You're pretty much in line with the 265/75/16, just an inch narrower tire.

 

What are your RPMs at 60 mph?

Correct. 

 

3.55 and 245s is 2k RPM at 66 MPH for my setup. Which is 3.69 final ratio.

I have 4:10s 265/75/16 tires auto w/HD Overdrive 4x4 dually '99 . At 75 mph im at 2600+- rpms. Bought new on 99 had 3:55s and with 265/75 was slow as ****. So $12-15k later not so slow anymore

I'm at 3.69 final ratio. 245/75 R16 tires vs. 265/75 R16 tires (stock). But I'm 3.55 geared axles. At 82 MPH turning exactly 2,500 RPM. Still getting upwards of 20 MPG. High RPM is not a issue and is way more efficient than 3.55 gears on 31.6" tires (265/75 R16) and use a 245/75 R16 which is 30.5" inch tires.

 

Beast can fry the tires in every gear but 5th gear.

 

 

Edited January 17Jan 17 by Mopar1973Man

So,I have an 01 with nv4500. 4x4. When I bought this thing a year ago it needed tires real bad . I bought it in Couer d alane, ID with 3 may pops and a will pop lol. Looking to buy tires before I drove I it home to Wa coast I ignorantly looked for 35’s and rims and would have bought them if they would have had them in stock. Thankfully I ended up buying stock size L285/75R16 on to the stock rims. Did all of these pick ups come with the same rear end gear ratio? How can I figure my gear ratio?

30 minutes ago, kbf98520 said:

Thankfully I ended up buying stock size L285/75R16 on to the stock rims.

 

The stock tire (listed in the driver side door jamb) is 245/75R16.  The trucks were actually sold with 265/75R16's.  Your tire is slightly larger diameter than stock.

 

30 minutes ago, kbf98520 said:

Did all of these pick ups come with the same rear end gear ratio?

 

Trucks came with either 3.55's or 4.10's.

 

30 minutes ago, kbf98520 said:

How can I figure my gear ratio?

 

My truck has 3.55 gears and 245/75R16 tires.  In direct 1:1 gear ratio (5th gear with my NV5600) , my tach reads about 2000 rpm at 50 mph.  If I had 4.10's, the tach would probably read about 2200 rpm.

 

Since you have an NV4500, you would need to use 4th gear (1:1 ratio) to make the same comparison.  Include a minor adjustment for your slightly larger tire diameter.

 

- John

Edited January 18Jan 18 by Tractorman

 

This is a older photo but 80 MPH to 2,450 plus or minus a few RPM.

Edited January 18Jan 18 by Mopar1973Man

1 hour ago, Mopar1973Man said:

This is a older photo but 80 MPH to 2,450 plus or minus a few RPM.

 

Since it is not in his signature, I will add that Moparman's transmission is a NV4500. 

 

I believe he is in 5th gear and running 245/75R16 tires in his photo.

 

- John

Edited January 18Jan 18 by Tractorman

5 minutes ago, Tractorman said:

 

Since it is not in his signature, I will add that Moparman's transmission is a NV4500. 

 

I believe he is in 5th gear and running 245/75R16 tires in his photo.

 

- John

Correct. 

 

NV4500 with 5th gear at 0.75:1 ratio.

245/75 R16 tires which are 30.5 inches.

Axle gear set 3.55:1.

2 hours ago, kbf98520 said:

How can I figure my gear ratio?

There is a tag in the glove box with the rear end size.   If the tag has disappeared, you can call the Dodge dealer's parts or service department and ask for the info from the factory build sheet.

 

This web site has an app to calculate final drive ratio with gear/tire size info.  

https://tiresize.com/gear-ratio-calculator/

 

 

If y'all would like to watch the entire rebuild of this Dana 80, my builder just got it edited and you can watch it on Facebook or YouTube. Just search Stratemann Automotive. Bring some popcorn you gonna need it.

Oof 16” tires…

 

Cant run 3rd Gen brakes with those.

On 2/5/2025 at 9:30 PM, Mace said:

Oof 16” tires…

 

Cant run 3rd Gen brakes with those.

Wouldn't wanna. 3rd Gen brakes add more rotational mass. Yeah I'm trying to fix my 3rd Gen right now it barely gets 14 MPG empty. 

Edited February 9Feb 9 by Mopar1973Man