see the pepole that are saying 4.88 also have a 5.2 you have about 30 horses more than them (stock)

 

You will notice a huge improvement with the 4.56's if you decide to go that way because you are so far undergeared right now. However, the 4.88's are the best choice in my opinion. The increase in unsprung weight and wind resistance due to the increase in height are factors that gearing charts just don't show you, but have real world influences on your available power. Alsothe difference between 4.56's and 4.88's at 65 mph is only 189rpm.

The other factor to consider is that you have already increased your tire size from the stock 30" tires to your current 37" size. You have the "Mod" bug. You probably cannot honestly say to yourself that 37" tires are where you plan to stay....can you?

So 4.88's may look a bit steep when looking at a chart, but with your truck being bigger and heavier the extra gearing can and will be helpful. Plus the 4.88's will work well with 38.5" - 39" tires (where the 4.56's will seem undergeared). Paying to regear twice is something you definetely don't want to do.

Go for the 4.88's!

As for availablity of gears, while 4 Wheel Parts is a large aftermarket 4wd accessory store, they don't sell anywhere near as many gears as Randy's Ring an Pinion, or even Performance Off Road Center does. Check with both of those sources and I am sure you will find that the 4.88's are available. The 4.88's were a recent new offering for the Dodge 9.25 rear axle just a year ago, so depending on when other guys were looking for them, they could have just been introduced and we all know what it is like to get a high demand new product. But they have been out for enough time now so I'm sure Randys or PORC has them.

Ask Silver how he likes his 4.56's with his 35" tires....lol

 

Whats the "Mod" bug? And yes I plan at staying with 37's, no need to go bigger with what gas milage im getting, and how much gas is, and will be up to next summer. Was even considering 35's at one time when I eventually buy new tires [Wont be for a year or two, these tires are fairly new]

So looks like 4.88 it is.

 

NOPE, stick with those 3.55's,those are MINT!

 

on the other hand if you do go down to 35' swith 4.88's you will be over geared like nhlbillsaid there is only 189 rpm diffrence between 4.46 and 4.88 and i belive thats in drive not OD, OD will be even less, talk to tose guys see what they tell you but you really do half to think of what dirrection you are going to take your truck, if you go opt got the smaller tires, or get bigger in the future is soething you really need to consider too

 

Yeah ryan is very right here. Make sure you know what your doing in the future for tire size berfore you choose what gearing you want to go with. If you are going with a 35" tire, 4.56 is beautiful. I have 4.10 gearing right now with 35" tires, and I feel like there are absolutely no issues, BUT..I'm sure if I drove it one day with 4.56's, I'd be a sad man. So unless I'm getting 4.56's, I'm pretending they do not even exist. But if you are concerned about gas, then I don't know if you want to stick with 37's or possibly bigger man. I mean don't get me wrong, big tires look sick, but if gas is an issue for you, then I'd suggest going down to like a 35" tire when you change. In my view, 35" is probably the best middle of the road tire. It's very big, yet is probably the biggest tire you can put out on the street while still having some realistic driving results. Any bigger, and your kind of subjecting your truck to a primarily offroad vehicle, which can be tough if its your daily driver. Besides, 35" defiantly is not small. Mechanics already hate me as is because they are very hard to balance and rotate and get allignments with, so they are tractor tire as is. The fact guys around here drive their trucks with anything bigger is amazing, because thats BIG lol.

 

There are lots of guys with daily drivers that have bigger than 35" tires.

I'm one of them. I have 38.5" tires and it's my primary source of transportation. I get 13mpg in the city which really isn't that much worse than what it got with 265's and 3.55 gearing (I got 16 once, but mostly it got 15mpg in the city). So 2 mpg is not a huge concern for me. As far as ride goes, my truck rides better now with 38.5" tires and long arms than it did with 35" tires and a short arm suspension. In fact it rides all most as nice as it did originally.

I think the biggest financial concern with lifting your truck is in the hard parts. Everything costs more on a larger truck. tires, wheels, the suspension, shocks, steering components, maintenance as parts wear out fast, etc....

So if your not financially preparred to purchase, install and maintain a lifted truck with tons of mod's (modifications for those asking what a mod is), then that is where it becomes exspensive to own and operate a big truck. I know of a few guys with bigger 2nd gen trucks than I have and with the proper engine mods are getting 16mpgout of them, so it's not the gas milage, considering 2nd gen Rams suck in that department right from the factory.....

 

That's a good point, although you are the extreme because you've basically transformed your truck in a 2500 lol. Most people aren't going to full out. The reality is, most people will big tires don't account for everything else, they just kind of whip the tires on and go with it, which is just going to make EVERYTHING treacherous if you don't do the right stuff. Obviously Nhlbill, you've done it all right, but most people wouldn't do the right things you have done ya know??

 

As for the rpms, check this site out. http://www.accuautoparts.com/#
Click on the "Calculators" tab towards the top on the right, and this will give you very realistic numbers. My truck runs at around 2,100 rpms at 70mph in OD now with the 37" (36.5") tires and 4.56 gears. This chart is fairly accurate. It was very helpful for me when I had my gearing done. Hope this helps.