Engine/Transmission (1998.5 - 2002) What mods are needed to run a set of 38's or 40's

[BRI7070]

I am looking into running a set of 38's or 40's on my truck and I was wondering how much lift would I need, what gear to run so my effective ratio would be around a 3. 73-3. 91 what performance mods to use, engine/transmission, for this set up? I would start with the engine/transmission upgrades, play with that until I save for the lift, gears, and tires to be installed at the same time.



early 01 2500 QC LB 4X4 auto 3. 54

 

[GotDodge]

Ok I can help but I need to no more info. What are you going to use your truck for? Like just show some offroading or what?Second! The stock power and transmission can move 38 or 40 with the right gears . So how fast do you want to get up to speed is going to determine how much power. Third! How much money do you what to spend. The reason I ask these questions is there is a lot of variables.

 

[tgbol]

a step ladder

 

[emjay]

As far as gearing goes, it's easy to figure out:



(new tire diameter/old tire diameter) * gear ratio = gear ratio needed to maintain current gearing. Similarly:



(old tire diameter/new tire diameter) * gear ratio = effective gear ratio if tires were stock.



For instance, say your stock tires are 30", and you want to put on 38" tires:



new gear needed = (38/30) * 3. 54 = 4. 48; 4. 56 is close



effective gear with new tires = (30/38) * 3. 54 = 2. 79



Keep in mind that there is a change in diff carriers at a certain ratio, i. e. carrier for 3. 54 and numerically lower may be different than a carrier for 3. 73 and numerically higher. I don't know off hand where the break is.

 

[csutton7]

skyjacker's new 7" lift claims you can run 40" tires---chris

 

[BRI7070]

GotDodge



What I am thinking about is a set of 22. 5" rims from a concrete truck. Machine a set of adapters to fit them and keeping the OEM center caps. Talked to some mechanics at the local concrete batch plants and they are getting over 60,000 miles on then and with my trucks total weight less than the weight on the front axle of their trucks I beleve that a 100,000 miles should be no problem. I looked into the cost of a set of those tires and they are around $275-$325 depending on size. As for the rims I saw a site that listed a price for Alcoa's at about $300. 00 each. Yes $2400. 00 is a lot but ,when replacing tires every 40,000 miles at $700. 00 a set... . wont take long to balance the cost. . Also 22. 5" rims would look cool



As for off road 15% of the time. but I am a speed freak so would need to get there quickly i. e. low 15's in the quarter.



emjay.

Thanks for the math formulas that will help. also thanks for the info on the carriers.

 

[Stefan Kondolay]

I run 37" super swampers SSR radials with a skyjacker 4. 5" lift and rear air bags. I have no clearance problems but 40's may be pushing it.



I run:

Diesel Dynamic Custom Huge Injectors

Edge Drag Comp

Diesel Dynamics HX40 w/16cm housing

stock exhaust manifold

Diesel Dynamics Cam

Pump Relocation Kit

Stock Lift Pump (after smoking several aftermarket ones)

DTT Transmission w/billet shafts

Custom Nitrous System



=12. 93 @ 109mph



and lots of:--)



My truck weighs 7975lbs. (last time weighed)

I had 3:54 gears / now have 4:10 gears (much better know)



I have found that all it takes is money. Have fun, I did.

 

[Oxjockey]

Check out this thread.



Bryan