4.11 Gears??? (1 Viewer)

[5280Hawk]

I did search this before i posted, and had no luck. I've seen folks on here that have them or have talked about them.

What are 4.11 gears, exactly? I am assuming it is a differential gear.

What does the 4.11 mean?

Why do I want it?

Where do I get it?

How do I install it?

 

[Mace]

it is the axle gear ratio.

Stock you have 3.70's. If you go to a 4.11 you will increase your RPM at any given speed. Nice if you need more power at highway driving, climbing hills, restarting at stoplights etc..

4.11's make your truck "feel" like you have more HP from stoplight to stoplight and pulling hills. But, you will lose the rubber overdrive (engine RPM drop for any given speed that comes with larger tires).

Any diff shop can get you a set and install them.

4.11 means the driveshaft has to turn 4.11 times for every single revolution of your tires..

 

[brokenparts]

4.11 is a gear ratio.. basically it means that the the pinion or driveshaft will turn 4.11 times for each rotation of the tires. The higher the ratio, the more times the the the engine, transmission, transfer case, etc turns to make the wheels spin which yields less top speed but more low end torque (usually).

When you put a larger diameter tire on the wheel the ratio is thrown off and going to a numerically larger diff ratio gets the ratio closer to what it was before the tire increase. Does that make sense?

You want it to get the power back after switching to larger tiress

There are many vendors who sell diff gears... Open up any 4wd magazine and you'll see the ads.

On just about every toyota the "third member" has to be pulled, and without getting too techincal the pinoin and ring gear are removed and the new set usually needs to be shimmed and replace back onto the axle. Probably want to have it professionally done...

how'd I do?

 

[Dynosoar]

4.11 gears are in the differentials. The number 4.11 represents a ratio such as 37/9 where the ring gear has 37 teeth and the pinion gear has 9 teeth. 37 divided by 9 equals 4.1111111111 this lower gear (higher numericaly) will allow the tires to turn more time per revolution of the drive shaft. (4.11 ring and pinion will turn the tire 4.11 times per single revolution of the drive shaft.)

Dynosoar

 

[5280Hawk]

Thanks for all the responses!

So it's More Turtle, less Rabbit.

I want to go the 33 x 10.50's eventually so that will help.

Does it effect the Gas mileage?

Is there a Kit?

 

[Dynosoar]

you guys type fast

 

[Stumpalama]

It will affect fuel mileage... sometimes for the better as your tire size is matched better with your gear ratio.
4.11 means approximately 4.1 turns of the driveshaft for one turn of your ring gear (read axle).
Much like a bicycle, changing gears changes the ratio of pedal cranks to tire rotations and the difficulty there-of.
Larger tires are easier to turn with "taller gears", but with taller gears comes higher RPM's for tire rotation.
"Search" should have much information on gear ratios vs. tire size. Check the other forums, like 40-55 etc...
HTH

 

[Mace]

So it's gearing down. More Turtle, less Rabbit.

Does it effect the Gas mileage?

Yep,

Depending on how badly your motor is out of range you can either increase or decreade mileage with a change of gear ratio.. There is not a simple answer. It all depends on what setup you are currently running, and how that setup is compared to the "ideal" RPM's of the motor..

 

[5280Hawk]

If you change the back differential to lower gear ratio does it mess up the front Differential?

 

[brokenparts]

So it's gearing down. More Turtle, less Rabbit.

Does it effect the Gas mileage?

it can... lower gear ration numbers will give you less power but better gas mileage especially on the highway. Lots of times you will hear people refer to ratio's like 3.73 or 3.55 as "highway gears". The best way to think about it is like riding a mtn bike. In the front it has 3 rings... a small one, a medium one, and a really large one (forget about the rear gears for simplicity). When you have the chain on the small gear you can climb hills really well and its fairly easy but you have to pedal pretty fast in order to not put your foot down... putting your foot down would be like stalling. This type of ratio is very efficent when "power" is needed but not very effiecent say if you wanted to ride to friends house that is miles down the street. Having it on the small gear up front would be like 5.29 gear ratio or 4.88 or something like that.

Now, if you want to get to friends house now that you got up that hill you'll wanna get there without having to pedal endlessly in that ratio so you switch to the Large or medium ring. It takes more effort to pedal while that chain is on those rings but you gain more distance each time you pedal... but once your up to speed it take little effort to keep going as long as there is not hill or obstacle to go over... hence the better gas mileage.

this making sense? This is pretty oversimplified but it should give you an idea?

 

[5280Hawk]

I just found this @ SOR - $233.00

 

[5280Hawk]

BP - that makes total sense. It would be just like installing a "bigger cog" in the back of your Mountain bike - or smaller in front.

More torque but less speed.

Thanks

 

[brokenparts]

just remember... you have two that need to be done. You have to change both the front and the rear if want it to run in 4wd without problem. You will also need an master install kit.

 

[Mace]

Broken has it.

Always do them as a pair..

Silly odd things happen if you have two different ratios front to back (do you want the rear tires trying to catch up to the front tires???)

 

[brokenparts]

BP - that makes total sense. It would be just like installing a "bigger cog" in the back of your Mountain bike - or smaller in front.

More torque but less speed.

Thanks

yes for the most part but also no... more torque faster which CAN mean faster speed intially but less TOP speed overall. Like mace said. The higher ratio will make it faster from street light to street light (and going up hills) but wont be as fast on the highway without excessive RPMs.

 

[5280Hawk]

Right, more torque and acceleration, but less (Speed/RPM) is a better way to say it.

So i would need Two 4.11 Ring Kits, and Two of these as well....

That's $706.00 at SOR - Wont be doing that for a while.

 

[Mace]

Add install to that price as well.

(no offense but if you have to ask these questions you want someone else to do it the first time)

 

[5280Hawk]

Is it that much harder than -say- the Knuckle rebuild? I just did that enitire thing myself.

Im not opposed to having someone else do it - better that than screwing it up.

 

[Captain23]

thats pretty fantastic, i was going to ask the same question this morning, and now a hour or two later, its not only answered, thoroughly,

MUD rocks!!

 

[Tinker]

IMHO you want an experienced FJ gear guy to do it every time.