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Wheels & Tires Semi-Tech General discussion of wheels and tires for the Ford Ranger.
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  #1  
Old 05-06-2007
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Help me understand gears...

So, I know that 4.11 differential means that the driveshaft has to rotate 4.11 times to turn the wheels once, right? Or am I right? If so, why are 4.11 gears quicker than 3.53? Or I'm probibly way off?

Someone school me!
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  #2  
Old 05-06-2007
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Quote:
Originally Posted by b3kbruiser
So, I know that 4.11 differential means that the driveshaft has to rotate 4.11 times to turn the wheels once, right? Or am I right? If so, why are 4.11 gears quicker than 3.53? Or I'm probibly way off?

Someone school me!

they are quicker if you keep the same tire size, so say if you had two 25 inch tires? and had one spinning with 3.73's and one spinning with 4.11's the 4.11s would spin quicker!
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Old 05-06-2007
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Why would the 4.11 spin quicker? If it takes the driveshaft 3.53 turns to turn the wheel, and the other 4.11 turns, why is the 4.11 quicker? It takes more turns?
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Old 05-06-2007
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Originally Posted by b3kbruiser
Why would the 4.11 spin quicker? If it takes the driveshaft 3.53 turns to turn the wheel, and the other 4.11 turns, why is the 4.11 quicker? It takes more turns?

because theres more teeth on the ring and pinion the driveshaft has to turn, and also when you put numerically higher gears the engine will also top out a lot sooner cuz the driveshaft has to spin that much quicker. so instead of the eninge turning at say 3000 rpm doing 80 mph then engine has to spin faster at like 3700 rpm just to get up to 80 mph.
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Old 05-06-2007
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Old 05-06-2007
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I think things are getting a little confusing. I don't believe it turns quicker for bigger gears.

The way I understand it is this. For ever turn that the driveshaft sends to the diff you get 1 / (gear ratio) in turns out to the wheel.

So if you have a 3.73 diff you get 1 / (3.73) = .269 turns at the wheel.
If you have a 4.10 gear you get 1 / (4.10) = .244 turns at the wheel.

So you will have a higher top end speed (assuming engine power is unlimited but engine revs are capped) with the smaller gear, but more power (since it takes more turns of the engine per wheel turn) with the bigger ratio gear.

Some one correct me if I'm wrong.
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  #7  
Old 05-06-2007
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Originally Posted by SniperX103
I think things are getting a little confusing. I don't believe it turns quicker for bigger gears.

The way I understand it is this. For ever turn that the driveshaft sends to the diff you get 1 / (gear ratio) in turns out to the wheel.

So if you have a 3.73 diff you get 1 / (3.73) = .269 turns at the wheel.
If you have a 4.10 gear you get 1 / (4.10) = .244 turns at the wheel.

So you will have a higher top end speed (assuming engine power is unlimited but engine revs are capped) with the smaller gear, but more power (since it takes more turns of the engine per wheel turn) with the bigger ratio gear.

Some one correct me if I'm wrong.

i believe its the opposite, for every 3.73 turns from the shaft you should get 1 full rotation at the wheel cuz the driveshaft will spin faster than the wheel because of its small diameter.
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Old 05-06-2007
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So... with a 3.53 geared, you get quicker acceleration, but a slower top speed.

With a 4.10, you get more torque, but slower acceleration?

I want my Camino to really burn some rubber and get up to speed quick, top speed doesn't matter to me because I'm not one to drive it to above 90mph for safety reasons... I should go with a lower gear like in the low 3s or 2s? Or is there something lower?
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Old 05-06-2007
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Originally Posted by b3kbruiser
So... with a 3.53 geared, you get quicker acceleration, but a slower top speed.

With a 4.10, you get more torque, but slower acceleration?

I want my Camino to really burn some rubber and get up to speed quick, top speed doesn't matter to me because I'm not one to drive it to above 90mph for safety reasons... I should go with a lower gear like in the low 3s or 2s? Or is there something lower?

to get good acceleration most musclar car guys put 4.11's cuz its quick off the line, good acceleration but then you do lose out at top speed, unless you have an overdrive gear. dpeneds on the tire size you want to run aswell.
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  #10  
Old 05-06-2007
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Originally Posted by blackbetty
to get good acceleration most musclar car guys put 4.11's cuz its quick off the line, good acceleration but then you do lose out at top speed, unless you have an overdrive gear. dpeneds on the tire size you want to run aswell.
Yup, 4 speed overdrive. So I should go for 4.11s, even though I have no idea how it works
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  #11  
Old 05-06-2007
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okay, the higher the ratio (ie. the number 4.11, 3.37) the more mechanical advantage your engine is gaining throught the drivetrain out to the wheels (that means higher torque numbers, quicker off the line, but a lower top speed).

The lower the ratio the less advantage the engine has through the drivetrain. (this means that you will see lower torque numbers, a little slower off the line, but have a theoretical higher top speed).

I hope this helps clear things up


If you think about it, you see threads all around here that talk about guys, (and girls) PC , wanting to change out their gears for larger ones because they need to turn larger tires. so basicly if you are looking for more torque you are lookin for a larger number gear set, and if you are looking for a higher top speed the you want a lower numbered gear set.
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  #12  
Old 05-06-2007
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Here's a reference most people can understand: Think of riding a bicycle with gears, the first (lowest) gear is the easiest to pedal on with the quickest acceleration but you quickly get to a top speed. Then think of starting out in the highest gear (smallest wheel sprocket), it's hard as crap to get that bike going and it puts more strain on you, but you can easily get to a higher top speed once you get it going.


With that said, the first (lowest) gear would be the 4.10's, while the highest (smallest sprocket) is the 3.73's and YOU'RE the engine. The 4.10's put less strain on the motor but limit the top speed. The 3.73's put more strain on the motor but in the end it gets you to the higher speeds.
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  #13  
Old 05-06-2007
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the lower the gear like 4.56s will get you off the line quick but with 25" tires you will get a low top speed. with 3.73s and same tires you will get a slower acceleration but a higher top speed.
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  #14  
Old 05-06-2007
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Ok for 4.10 gears for every one turn of the drive shaft your tires will have rotated a complete 4.10 times. With 3.73 gears your tires will have rotated 3.73 times. So with the 4.10's you will have better acceleration but a lower top speed but seeing as how we have a truck your top speed is going to be limited by your horsepower. So 4.10's are better gears to have.
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  #15  
Old 05-06-2007
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Quote:
Originally Posted by DaGGer
Ok for 4.10 gears for every one turn of the drive shaft your tires will have rotated a complete 4.10 times. With 3.73 gears your tires will have rotated 3.73 times. So with the 4.10's you will have better acceleration but a lower top speed but seeing as how we have a truck your top speed is going to be limited by your horsepower. So 4.10's are better gears to have.
You got what turns at what rate turned around. With 4.10's, that's how many times the driveshaft turns before the wheels make one full rotation. If gears worked how you said we'd all be going over 300MPH.
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  #16  
Old 05-06-2007
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Quote:
Originally Posted by DaGGer
Ok for 4.10 gears for every one turn of the drive shaft your tires will have rotated a complete 4.10 times. With 3.73 gears your tires will have rotated 3.73 times. So with the 4.10's you will have better acceleration but a lower top speed but seeing as how we have a truck your top speed is going to be limited by your horsepower. So 4.10's are better gears to have.
You've got it backwards.

It takes 4.10 revolutions of the driveshaft to cause the wheels to complete one full rotation. This gives you the mechanical advantage as was explained earlier by applying more torque to the wheels. This will give you better acceleration because it allows the motor to start the wheels spinning more easily. Lower gears are also ideal for off-road applications because it allows more torque to help get those bigger, heavier tires spinning or to give you more torque to pull you up and over the next rock.

Higher gears (numerically lower) will allow the tires to spin closer to the speed the engine is spinning, providing a better top speed at the expense of usable torque.
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  #17  
Old 05-06-2007
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Oooookay I get it now, with the 4.10s the engine doesn't have to work as hard, so it end up going faster... Right?
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  #18  
Old 05-07-2007
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I had 3.55's stock in my 4.0. I then replaced them with the 4.10s because it gives you more low end torque and modifys your torque curve. This gives you better off the line power and better low end torque making it easier to off road assuming your driving around in 4 low and first gear for example. Being that it is a truck also I am not worried about top end. Mostly I wanted a quicker 0-60 and I got that with 4.10s. Also I get a little better gas mileage as my engine does not work as hard to keep with traffic. Bascially a huge difference is when I push the gas just enough to make the auto trans shift at 2 grand everytime. Even at 2 grand 95% of the time I pull away from everyone at the light.

Its because of the bama chip and the 4.10s.

Personally if you want a quick car from 0-60 Id maybe think of 4.88s depending on how the tranny is geared.
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  #19  
Old 05-07-2007
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Originally Posted by IR0NS1N
Personally if you want a quick car from 0-60 Id maybe think of 4.88s depending on how the tranny is geared.

Stock 4 speed overdrive Hydra-matic... Not sure of the gearing
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  #20  
Old 05-07-2007
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Quote:
Originally Posted by Oh5Edge
Here's a reference most people can understand: Think of riding a bicycle with gears, the first (lowest) gear is the easiest to pedal on with the quickest acceleration but you quickly get to a top speed. Then think of starting out in the highest gear (smallest wheel sprocket), it's hard as crap to get that bike going and it puts more strain on you, but you can easily get to a higher top speed once you get it going.


With that said, the first (lowest) gear would be the 4.10's, while the highest (smallest sprocket) is the 3.73's and YOU'RE the engine. The 4.10's put less strain on the motor but limit the top speed. The 3.73's put more strain on the motor but in the end it gets you to the higher speeds.

That's a good analogy. Never even thought about a bike, but it makes perfect sense.
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  #21  
Old 05-07-2007
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Quote:
Originally Posted by Oh5Edge

With that said, the first (lowest) gear would be the 4.10's, while the highest (smallest sprocket) is the 3.73's and YOU'RE the engine. The 4.10's put less strain on the motor but limit the top speed. The 3.73's put more strain on the motor but in the end it gets you to the higher speeds.
so that means with two stock Rangers...the one with 3.73's will go faster than the one with 4.10's in the end?
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  #22  
Old 05-07-2007
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Quote:
Originally Posted by buzzair
so that means with two stock Rangers...the one with 3.73's will go faster than the one with 4.10's in the end?
Yes, the Ranger with 4.10's will beat the other off the line but the Ranger with 3.73's can get to a higher top speed in the end.
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  #23  
Old 05-07-2007
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Quote:
Originally Posted by Oh5Edge
Yes, the Ranger with 4.10's will beat the other off the line but the Ranger with 3.73's can get to a higher top speed in the end.

yeah, so if you are on a long road race, the 4.10s will beat the 3.73s off the line, but theres a chance the 4.10s will max out their top speed and then the 3.73s can catch up and pass
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  #24  
Old 05-08-2007
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Originally Posted by SniperX103
That's a good analogy. Never even thought about a bike, but it makes perfect sense.
It's the same with a transmission. In first gear, you have a lower gear ratio which multiplies the torque to get you started moving. That's why you can only go like 30 mph in 1st, where your ratio is low, but in 5th (overdrive) your driveshaft is actually spinning faster than the engine, which means you can cruise the highway at lower RPMs. That's also why you really have to floor it to start off in higher gears like 3rd or 4th.
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  #25  
Old 05-08-2007
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Man i understand gearing fine. But this thread is enough to confuse anyone.
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