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What gears work best??

3K views 11 replies 5 participants last post by  snrusnak 
#1 ·
I have a '12 Ram 1500 and am looking into changing the gears in the rear end based on advice from this forum it seems like this will help me with acceleration and overall low end torque. I currently have the 3.55 gears and want to know what gearing I should look into for my application? I dont do alot of towing but do occasionally once a month tow a 20 ft. boat but my main driving is around town and highway miles.
 
#2 ·
if you don't tow or run big tires I see no reason to spend the money on a gear change. I don't think the results will outweigh the costs.

main reasons for changing gears are guys who run big heavy tires to help turn them better or guys that are modding their truck to be fast at the track.
daily driving I don't think you'd be satisfied with a gear change. that's just my opinion and something to think about. plus if you are 4wd then you have to change front and rear gears and I think a gear swap in a 2012 is a bit complicated and more expensive because of the carrier.
 
#3 ·
if you don't tow or run big tires I see no reason to spend the money on a gear change. I don't think the results will outweigh the costs.

main reasons for changing gears are guys who run big heavy tires to help turn them better or guys that are modding their truck to be fast at the track.
daily driving I don't think you'd be satisfied with a gear change. that's just my opinion and something to think about. plus if you are 4wd then you have to change front and rear gears and I think a gear swap in a 2012 is a bit complicated and more expensive because of the carrier.
Thanks for the quick response! I see what you mean about maybe not being worth it now within the next 3 months I will be towing @ a 10ft enclosed trailer on a regular basis with tools so I'm trying to get ideas for the future on what might make that an easier job for my truck besides swapping a HEMI in it! :LOL:
 
#8 ·
"It's the ratio of how many times the drive shaft turns to how many times the axle turns and is set up by choosing how many teeth are on the ring and pinion gears.

Bottom line, the higher the ratio, the more power (Torque actually) at the rear wheels, also the higher your engine runs (RPM's) and the poorer your gas mileage.

btw - higher ratio is reffered to as lower gearing (geared down) and lower ratio is reffered to as higher gearing ... nice and confusing eh?

example, with a 4.10 gear set, the ratio is 4.10 to 1 so for every 4.1turns of the driveshaft, the rear axle will be turned one time and you will have a torque advantage of 4.1x
On the flip side for every say 10 turns of the wheels, your drive shaft will turn 41 times & your engine has to turn 41 times in high gear (not overdrive).
With a 3.70 gear, your Torque advantage is 3.7 times but now if your wheels turn 10 times, your drive shaft and engine will only turn 37 times. As with everything auto, always a trade off."

-disclaimer, not my words. explanation from someone else
Holy crap thats confusing:LOL:
BTW: thanks for trying lol
 
#9 ·
#11 ·
Example: I changed from the stock 3.92 to 4.56. My around town mileage went up a bit (when I can keep my foot of it...) because the engine isn't working as hard to get the truck moving. When I get out on the highway, mileage suffers because now to maintain the same speed I did before, the engine is spinning faster (higher rpm). It's always a trade off, unless you can adapt another OD gear to it lol.
 
#12 ·
Basically you need to decide if you care about mpg or not, and if so, how much do you care?

3.55 give pretty good mpg on the highway. 3.92/4.10's won't be horrible at 70mph but you will likely lose a little mpg. Now if you cruise at 80 or higher with that gearing you will get bad mpg. 4.56 mpg on the highway really suffers, and if you cruise at 80+ you'd be getting terrible mpg.

With my 3.55, I can cruise at 70mpg and get over 20mpg easily. At 80 mph I can still sometimes get 20mpg, depending on conditions. And even at 85, 90 mpg(yes I sometimes drive that fast) I will still get anywhere from 17-20mpg again depending on conditions(mainly how windy it is). Keep in mind too this is all unloaded, not hauling or towing any weight. At 70mph though, the truck can feel a bit sluggish cruising when you pass someone, sometimes it has to kick down a gear to really get up and go.

I've experimented locking out the 6th gear and cruising around with the 5th gear on the highway, which is effectively the same as having 3.92 or 4.10 in the 6th gear(don't remember which one off hand without doing the math). What I found was that probably 75% of the time I still got 20mpg or higher pretty easily, unless it was very windy. When you start going over 70mph, mpg drops off pretty quickly. The truck had way more power on demand though, which I really liked.

Personally, I would never go as high as 4.56's, but I drive on the highway occasionally. I don't do highway driving a lot, but we go half way across the country a few times a year, and that gearing would really put a damper on those trips. If I was only around town, then yeah I'd regear to 4.56, as it's only going to help. If you do highway driving, I wouldn't recommend anything higher than 4.10, and even with that you're limited to around 70mph cruising if you want to see any decent mpg.
 
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