Front/Rear End Ratio

[LarryG]

I'm only 3700 miles into dieseling so I need to know everything. I accepted the dealer's inventory which included 4:10 rear/front end. Thought I could accept it. But, while I'm not towing anything can I go to larger (19") wheels/tires to slow down the RPM's/get better mileage? Are they available for the 2500? Truck is telling me I'm getting 14. 5 mpg combination highway/local commuting I figure it's probably cheaper/quicker than changing out differentials. Truck is stock 2002 Ram 2500 QC SLT Lariat, 4WD, auto, SB , 24V Cummins. Love my truck.

 

[klenger]

I have about 6500 miles on my truck. Doing mostly city local and city freeway driving, my overhead computer will tell me I'm getting about 15. 9 MPG. When I calculate the actual milage, it's usually about 17. 3 MPG. I figure that's not too bad for a truck with 4. 10's and city driving. I think it's better than my '98 Grand Cherokee 5. 2L V8 got.

 

[MCummings]

if I recall correctly most 19. 5" rims (The popular size) are speed rated to only 65MPH.



Just a heads up.



I priced 19. 5" for my 6 wheeled truck and came out to be $4,500

a differential change out with a front locker should be about $2,500

and an Overdrive unit shoud be around $2,000



BTW you could go all the way to a 3. 23 rear-end ratio,, there is a good company that carries that gear ratio for the Heavy Duty Dana's (70-80 series) I can't recall the name, but the gears are special order and have about a 3 week or was that 3- month? backorder/special order waiting time.



I think the compnay name was Reider racing. reiderracing.com ??



Merrick Cummings Jr

 

[LarryG]

Thanks, I guess I was wrong about costs. And while I'm full of questions, does anybody use breakaway hubs on 4WD's anymore? I don't recall seeing them on the newer trucks.

 

[Pit Bull]

If you are thinking about doing either of these changes to save money it is not a good idea. If you changed diff's and picked up 2 mpg, it would take your 20 years to break even if you averaged driving 20,000 miles per year I would suggest that you wait until you need a new set of tires and then go to the 19. 5's. They will last for around 150K miles and give you the better ratio.

 

[Diesel Dan]

Igould,

the easiest and cheepest way to achieve this lowering of rpm's is to go to 295/75r/16's they fit purfectly on the stock rims and will lower the ratio to apx 3. 73 and they look awsome. When i got my truck i didn't get home from the dealer before going to my tire guy for 295's this will drop you apx 200 rpm on the freeway. i recommend bfg's ATKO's they are a great all around tire with excellent street traction and great offroad traction in everything except gumbo mud and how oftem do you play in gumbo?hopefully not much in our heavy tanks. also you can trade in your spare while you are at it and replace it with a mostly used (apx 25% left) tire and it will barely slide up under the back. mine has apx 1/8 th of an inch gap between the rails. and is already tested



Best of luck



DD