I know i know, it's like asking "what is the function of the steering wheel?".... but yes... i kinda understand but i want to KNOW.

 

in very simplistic terms lockers will force both wheels on an axel to turn at the same rate with power distributed evenly between the 2 tires. without a locker, the wheels on the same axel will turn at different rates depending on direction of travel and resistance on the wheels. If you were to spin your tires without lockers, the tire with the least amount of traction would spin and the other tire would not move. now add lockers and both tires on the same axel would spin. in a vehicle equiped with open diffs (Rubicon), in 2wd only 1 of the rear tires actually gets power to propel your vehicle. in 4wd only 1 rear and 1 front tire recieve power to propel your vehicle (this is a 100% traction addition over 2wd). with lockers front and rear, all 4 tires recieve power (this is a 100% traction addition over 4wd!). it ultimately is alittle more complex than this when taking into account substrate, vehicle weights, limited slip differentials, brake lock differentials etc... but this is a very simplistic explanation.

 

Great, exactly what i was looking for, and that's kinda 'exactly' what i thought it was... with one difference... i didn't knew that when in 4WD (i assume 4HI or 4LO is the same) only one wheel on every axle gets power...

Now, i still have a doubt... if with lockers, both wheels on same axles are LOCKED, why do i see wheels spinning differently in this video, exactly in time 01:09 and 02:20 notice how one rear tire stops and the other one spins. (i assume that lockers are needed and engaged at that moment)

https://www.jk-forum.com/forums/show...awhammer-Trail

 

I don't really think its that stupid of a question. While most people realize a locker gives them added traction, the specifics of the torque distribution is a little unclear...

With a locked differential (for simplicity, assuming a RWD vehicle), the sum of the traction available between the two rear tires is available to move the vehicle forward (assuming the powertrain can provide it). The tires will also always spin at the same speed, and the torque can be split between the tires depending on the traction available to each.

An open differential, IMO, is more complicated to understand. The tires can now spin at different speeds (for turns, slipping tires), but the torque split is always 50/50, no matter how good or bad that is.

What I mean by bad is this: if for example the right tire is in the air, and there is only a bit of dragging loss (from bearings, seals, etc.) of say 10 ft-lb, then only 10 ft-lb is available to the left tire to move the vehicle forward. If its not enough (which it likely isn't), then the vehicle will not move (the tire in the air will spin, the one on the ground with traction will not).

A locked differential in this situation is able to send the torque to the tire that has traction. So the right tire will still see the 10 ft-lb, but the left tire with traction can react a much higher amount and move the vehicle forward. Once again assuming the powertrain can provide the amount needed.

Hope this helps.

 

Its possible with an open differential to only have power go to one tire... such as when a vehicle is stuck in snow and only one tire spins. Driving down the road, with both/all tires having good traction, power will go to every tire.

 

Not true. Both wheels on each axle will split the torque. It just so happens that the differential will always send most (if not all) torque down the path of least resistance; the wheel with the least amount of traction will get more torque ... because it's the path of least resistance. If you read up on differentials, you will see how/why this happens.

Unfortunately, the path of least resistance is usually a tire that's in the air, in mud, in snow, in ice, and so on. That means that all of the power is being sent to something that has no traction and can do nothing with it. The wheel/tire *with* traction literally gets robbed.

The locker forces the differential to send equal power to each wheel on that axle; it takes out the "path of least resistance" factor. The wheel/tire *with* traction will then get 50 percent of the available torque ... and hopefully has enough traction to move the vehicle.

I hope this helps.

-Dawn

 

I think you have torque and power mixed up in a few places...

Open differential will always split the torque 50/50 to the tires, but not necessarily the power, as the tires can spin at different speeds.

Locked differential will always spin the tires at the same speed, but not necessarily split the torque or the power evenly.

 

Lockers were not engaged at 2:20 in the video, unless they were engaged literally just as/before the Jeep regained forward momentum. The right rear wheel had less traction, so it spun more freely and received more torque than the left wheel. But yeah, this is definitely a case where lockers would make a difference.

 

If you want to get more technical, you have a few things mixed up, too. I'm too busy to go there though. The point here is to explain the function of lockers to a noob more than the physics. I think he now has what he needs to know.

 

I guess I'd like to know what I have wrong so I can fix it?

To the OP: summary is open and locked differentials are both ideal in certain situations. On-road the open diff is simple, cheap, and gives good performance for the average driver. Off-road lockers are ideal in many situations to get power to the tire(s) that have good traction.