I have heard that for 33's, a 4.56 ratio will bring you close to, let's use a stock FX4 with 4.10 and 31's for example.

I currently have 4.10 on 33's. At 65 I'm at @ 2500rpm, and that's in O/D on my manual tranny. If I were to go to 4.56, math says I will be close to 2800 at 65mph. But 4.56/33's would be "closer to stock" than my current 4.10/33's, thus reducing drag on the engine and drivetrain compared to what I have now. So if I got 4.56, would my mileage go up or down? Seems like it could go either way, given the factors.

BTW, Is a stock Ranger with 4.10s and 31's really doing 2,800rpm at 65mph? I think someone here reported @2300 at 65mph on their 31's/4.10s. This is where I get confused.

 

My truck has 4.10's and 30's if I remember right. At 65 mph I'm doing about 2400 or so.

 

Keep in mind a manual and automatic transmission will end up at different rpm, even if they end up at the same ratio due to the slip in the torque converter. Also keep in mind that not everyone has proplerly calibrated speedometers so the numbers you hear will typically vary by a couple hundred.
Your mileage could potentially go either way. Generally I would say it would increase but driving habits and terrain will make a bi difference. A person in a very flat area who drives easily and doesn't tow/haul/off road much might benefit more from 4.10s but I would say that is the exception.
Either way the cost of regearing doesn't make up for mileage, you re-gear more for performance of to decease stress on the drivetrain IMO.

 

Yeah. So on 31's you'd be slightly lower, prob 2250-2300. But if I were to drop down to 31's, I'd be hitting like 2800 on my 4.10's, since I'm currently at 2450-2500 on 33's at that speed. I'm ultra confused.

Yea thats why Im confused, I figured my RPMs would be even lower due to the manual trans. And I do compensate for the speedo difference when I arrive at these numbers. At 65mph my speedo says ~58. At 80mph my speedo says 65. lol. And yeah I'm just wondering about this because I'm considering going to 4.56 or 4.3 when I get a locker

 

On my truck 33s/4.10's is the same as stock. IDK how big my tires were but I had 3.73 gears factory. My speedometer is like literally 100% accurate now that I put the 4.10 rear end in it. What gears did your truck come with factory?

 

You probably had somewhere around 255's or 30 - 30.5's.
Stock I had 3.55. I briefly had my 31's with my 4.10's but it was so brief I can't remember what my rpm's were on the freeway. Speedo was inaccurate as hell with 3.55's and 31's. When I regeared to 4.10 it was decently accurate again with the 31s, I remember that much. Now with 33s it's so inaccurate it's funny.

 

Yeah mine was around 15% too slow if I remember right with the 3.73's? 4.56's is probably what would be ideal for you. You're lucky you live a Cali too since thats like prerunner ranger heaven theres axles with 4.56's already installed always for sale on the forums and stuff.

 

So you didn't have to get a programmer or anything to get your speedo 100% accurate with your 33's and 4.10's?
4.56 would be cool on my truck but I don't really want it anymore, I'm on the highway alot these days. I'm even kinda reluctant to do 4.3 but I really would like to get a little low end back. Hoping it'll work out perfect.

 

Nope, just got lucky I guess lol

 

thats fawkin rad. I'm jealous

 

when my speedometer says 55 going down the freeway im really doing 65 and my rpms are i think around 2700, maybe its been a while since ive driven on the freeway lol and ive got 4:10s

 

do u remember what it was with the 31's?

 

Normally I would say just go for the 4.56 gears. But being a regular cab 2wd, 4.30s would be okay as well I think.

A gearing calculator says that coming from 31s and 4.10s, you would need 4.36 gears for 33" tires. So 4.30s would be nearly identical aside from the extra weight and drag from the 33s.

 

No I don't... And I drove on the freeway yesterday and looked and I was actually around 2300-2400 when my speedo said 55