Hey y'all! I saw something in this article I found a little confusing. It was about switching a stock truck with a 3.08 rear and stock tires to 33" ones requires about a 3.73 to get back the stock gear ratio "feel." It also said something like "... and going to a 4.10 would be nice for towing and 4.56 for better wheeling..." My question is are they saying for towing the 4.10 is better than a 4.56 on 33's? If so why? I thought the 4.56's would be equally desirable in a tow vehicle as a pure 'wheelin' ride since it means more torque and better speed control...  

The 4.56s would run too high of rpm at 60 on the road and suck alot o gass too.  

Can you explain to me what 'gear ratio feel' is?  I might also need to understand this question your asking, lol.

I am planning to switch to 33" tires, on my dodge ram 4x4. Since buying this truck, I know I need to find out what I have all the way around, but What do I need to find out beforehand? Before making any mods or switching tire sizes?

I know it'd suck a lot of gas with 4.56's and 33's with a 1:1 3rd gear, but this tranny has the 0.70:1 overdrive making the rpm 1950 @ 60 mph! That sounds like the engine is barely above lugging it to me! With the 4.10's it'd be chugging along at 1753 rpm and 3.73 at 1595. Is the 4.56 still an undesirable choice in this situation?

Cinderz, I meant that with 3.73's it'd run like stock, feeling like stock gears. Other people'd say it'd bring your stock gears back but other people'd argue that gear ratio don't change when you change tire diameter.

If thats the rpm u wana run Id definatly go with the 4.56s if thats what its going to be it would be much more responsive.  

Hey pwrwgn! So are you saying you think the 4.56's sound good for towing with 33's and a 0.70:1 overdrive? I'd like to hear anyone's opinion on what are desirable cruising rpms for towing with a gas engine (or diesel). I've never done it but I guessing anywhere from 1500-3200 rpm is a good cruise rpm...  

Thanks for answering... I just might understand! lol

But from what I am hearing on this topic, it sounds to me like going with the 3.73 makes the best choice, so not to go over or under. You can always change it up later but I doubt you will need to.

Yes I think that any lower rpm would be too low and oout of the power  range for towing, The tranny might keep shifting up and down. Id go with the 4.56's. A diesel is totaly diffrent its power  comes way lower  and would probably be best at about 1200 rpms but dont quote me the only diesels i drive are Army Rigs and they dont hardly go over 2000 rpms, EVER.  

Changing tire size does not change the gear ratio is true to a point. Your ring and pinion gears are the same ratio regardless for tire size, HOWEVER it will change the "effective ratio" that the drivetrain places on the engine. If you have 3.73's with stock tires (30") and you leave everything else the same and just change the tire size to 33's (about 10% increase), the the effective ratio will be about 10% drop in performance. For example say you have 30" tires stock and go up about 10% to 33" the effective ratio will be about 10% less, the truck will feel like it would with stock tires with higher gears (numerically lower) (3.73X.9=3.35) (about 3.42s) A tire size change of less than 10% is usually OK with stock gears. Any larger than 10% and you'll want to swap lower gears.

I had 3.73's and a 5 speed manual overdrive, stock with 265-75R16 (about 29.5" tall) and ran 33's for awhile with no trouble, but when I installed 35's, performance suffered and I swapped 4.56's which work great. Personally, I think 4.56's will be too low with 33's on the highway. 4.10's would probably give you the best compromise for on road towing and off road performance. However, if you have 35" or larger tires in your future, I'd go ahead and swap 4.56's so you don't end up swapping gears twice.

Hey guidolyons! I know people's suggestions about good freeway gearing is mostly relative to each driver's personal preference. Well I dislike driving over 86 mph on public roads. Where I live, most of the time I don't cruise over 70mph. Do you still think 4.10's would be better?  

I spent a lot of time at Randy's Ring and Pinion website gear ratio calculator figuring different tire size, tranny gear, and ring and pinion ratio's before selecting the 4.56s with 35's

http://www.ring-pinion.com/calculators/calculatorsind.html

Don't forget to use the actual tire height, not what's printed on the sidewall to make your calculations. You can figure for different speeds not just 60mph. with 33's, either 4.10 or 4.56 will work, it just depends on what you need your truck for.  With 33's, 4.56's will spin about 300 RPM faster than the 4.10's which is not that much diference.  4.56's will run about 2263 RPM in 5th gear  v/s 2035 RPM for the 4.10's. Ideally cruising in 5th gear should be around 2,000 RPM.

I hope that helps.

What?!? A truck cruises nicely at 2000 rpm? I guess the reason I'm surprised is because I'm used to driving a 1993 Grand Caravan. It weighs 4150 lbs and has a torque peak of 183 ft lbs at 3600 rpm although its horsepower peak is still 147 hp at 4800 rpm. That motor has NO PULL below 2000 rpm. It's just startin' to wake up there! It doesn't make decent torque until 2500 rpm and sadly when you hit the gas off an on-ramp you usually have to wait 3- 5 seconds for it to hit it's peak torque between 3000rpm and 3800 rpm. I hate how peaky that torque curve is on the '93 3.3L V6. (Feel free to poke fun at minivans too!)

I would have thought the ideal general cruise speed was between 2250 and 2800 and the fastest ideal cruise speed between 2450 and 3150 rpm.

2000 rpm ain't slow enough that the tranny might automatically downshift? I know THAT would be bad while towing.