Ok, I put Dana 70 in front and Dana 80 in the rear of my 1500 with 3/4 ton diesel coils in the front. So essentially my truck is now a 2500. What i need to know is what is the largest tire that I can go with without having to do much more than a levelling kit for the front? I'm thinking 315 75 r16 should fit but want some opinions.

 

35's with just a level. Should fit no problems.

 

2500s have different frames and wider leaf spring packs with different GVW. Not to mention different transmissions. But you're close, I guess. One can get 35s on a 1500 with a 3" lift so the taller frame and coils should clear it. Depends on the brand of tires. Some run large, some run small.

 

To my knowledge there is no difference in the frames from the 1500 to the 3500. I know there was no frame difference between a 97 1500 and late 98 2500 from my cab swap. Just curious where you're getting that info.
Otherwise you are correct.

 

Ya the 1500 frame is different than the 2500. 2500 is a lot heavier. At least compared from a 96 2500 to a 01 1500

 

Transmissions are the same too... aside from the diesel, and V-10.....

 

Sorry but they are not different. I cut apart both a 01 1500 and 01 2500 they both have the same frames with the same thickness. What gives you the higher GAVE is the axles, more springs, and usually thicker coils. Now with diesel you get even more ( even the V-10) by heavier engine and even heavier springs. Take the 2500 LD had the same axles as a 1500 with just more springs but same frame. ALL-PAR has an article on where they tear down a 1500 and a 2500 LD and they are the same except some 2500LD did have front D60

 

(Yes, I was referring to V10/CTD HDs trans since who would get an HD for the 5.9/46?)

So apparently, the whole internet has been wrong all these years. All of our posts and various forums (I've been on since 2005 on forums) always claimed that the HDs had bigger/ taller frames. Even my memory says that my ex's 2500 v10 had a much larger frame than mine. There's also people who claim their cummins has a taller frame than their 1500.

This is the only frame dimensions I could find ANYWHERE. Notice it only mentions differences in the chassis/cab 2500/3500:
http://dodgeram.info/2001/dimensions.html

This is the only schematic I could find ANYWHERE:
https://www.dieseltruckresource.com/...rences-326677/

No one has ever recommended or claimed to do a cummins swap in a 1500 until this guy. Notice he completely changed the suspension and modified the frame:

http://www.pirate4x4.com/forum/dodge...mins-swap.html

here he is again on here:
https://dodgeforum.com/forum/2nd-gen...cummins-3.html

Here's a guy that claims the cummins frame is much taller than the gasser, as well as a guy betting that the frame is thicker:
https://www.turbodieselregister.com/...-vs-2500-frame

So apparently, unless we all go and measure our trucks at the same places with calipers for thickness for proof, we were all wrong all these years. Maybe the HD frame had a bit thicker steel, or higher tensil properties, but it sure looks like Dodge used the same frame for all models.

I'm going to go eat my crow breakfast now. . . .

 

It's really good with Ketchup.

 

I scraped a 01 2500 CTD and an 01 1500. Had to cut the frames no title. I have the pictures somewhere I can get for you they are identical and the same thickness with a caliper. They where the same wheelbase trucks. I'm not trying to argue (as I don't know everything) in just trying to let me know what I know or have found out. Isn't that the internet was intended for lol