Home Forums Hunting & Shooting Hunter's Campfire gear ratio, rear axle in pick up

I am probably the only guy on this board that does not understand this.

What impact will different rear axle ratios have on a pick up.

I am about to buy a new one and can get 3.08 or 3.42 rear end ratio.

Thanks

In Minnie Soda, I'd go 3.42, in Tx. 3.08.

Lower # less rpm's per given miles per hour.

and just to be clear, higher # is better towing and acceleration

ked

I would go 3.42 regardless of were you live.Everything has overdrive nowdays.It all boils down to how many times the driveshaft has to turn to turn the tires once.a 4.11 means the shaft turns a little over 4 times to turn the tires once,and a 3.07 means the shaft only needs to turn a little over 3 times..The higher the munber of your gear ratio the lower geared you actually are .Low gears give more power,and higher gears give you reduced rpm..

I just notice were you live .I would try and get a limited slip rear differential .

What's the rest of the info on the truck (make/model/engine)? Do you plan to tow? If yes, what?

Well I am in Texas, and have a 3.73. Good for pulling power, but a bit taller than I really need. Ford sells them with 3.55's and I wish I had held out for that ratio. The engines revs at a given speed are proportionately less.

3.55 is what i like.

3,55 is good for a street rod also.

I think both our '14 F150's are 3.55, both are 5.0.

The 3.42 ratio will have your engine turning more rpm's at a given speed than the 3.08 ratio will. For example, say at 60 mph in top gear your engine is turning 2200 rpm's with the 3.42 ratio, it would run at 2000 or so with the 3.08 gears. This means that the 3.42 gears would pull a little better when towing since the higher rpm's put you more into the engine's power band. The downside is that it'll likely give you a little less fuel economy than the 3.08's.

If you're planning on putting bigger tires on the truck then you want the 3.42 gears since going to a bigger tire effectively reduces the gearing. To get an informed answer we need to know what truck, engine, and transmission you're talking about though. Everything's a compromise with gearing and what's good for one combination isn't good for another. The final drive ratio of the transmission matters as much as the rear end gearing.

As one poster said, always get the limited slip or e-locker type rear end, don't buy a truck without that.

My old super duty 250 with 5.4 has the 4.11s with 5 speed,and I run it 75,and 80 on the interstate..My Ranger has 3.73s and I wish it had a lower gear because it only has a 3.0,they do both have the limited slips though.

Definitely 3.42, especially if you need to haul anything. Bigger number means higher rpm's and more pulling power. You "might" get better mileage with 3.08s but with overdrive transmissions you'll probably downshift on the slightest of hills negating any gain.

What the number means is the number of revolutions the drive shaft will make for each revolution of the axle. There are a limited number of ratios because of how the gears mesh, 3.08, 3.55, 3.73, etc. The higher the number, the faster the driveshaft has to turn and the lower the gearing.
Since the driveshaft, hence the engine, turn faster at the lower ratios, you get more power but less fuel mileage and road speed for a given engine speed.

I appreciate all the comments

Other info-
It will be a Chev Silverado
5.3L engine
4WD
I don't tow anything
Use will be highway and hunting
The hunting will be off road but nothing extreme, farm fields etc

Don't get the 3:08 gears.

If you have need for a 4x4, then you wouldn't be satisfied with the 3:08 gearing.

3:42 is a happy medium.

I disagree, with a transfer case and low range 3.08 will be fine especially if your not towing anything. Been there had 2, a Blazer and a K1500 with 2.73 rears and 305 V8 and had no issues off road in Maine with either. YMMV

[bleep] i drove my dodge dart around with 4.88s but it would turn 8 grand no problem.

running a 28 inch tall tire.

I have run pickups with gears ranging from 2.72 to 5.42. With today's overdrive transmissions, I will never own another truck with taller gears than a 4.10. But I use a truck for hauling and towing, sometimes up to a combined gross weight approaching 20,000 lbs.

If a guy never throws more than a ton in the back of his pickup, and never pulls a heavy trailer, he could get along quite well with today's high output engines and a five or six speed tranny combined with 3.08 gears.

Just shift it into low range when you leave the road.

Run 3.55 in my dodge v8 4x4 w/low range and with the over drive it is a great highway cruiser. I do a lot of off-road driving in the Sierra's and would like the 3.90 option next time.