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Old 05-10-2007, 08:45 AM
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Lightbulb Locker Basics

Locker Basics:

Hum Where to start.
When People say lockers they can mean many different things.
So I am going to start with Axle differential options and break it down from there.

Your basic Stock axle is what is called Open.
This means that there is a set of spider gears that take the power from the Ring and pinion and transfer it to one wheel. (The wheel with the least amount of resistance.) If both wheels have the same amount of resistance it kinda splits the power between them but as soon as one wheel looses traction it get all the power and the other one gets nothing.

Your next upgrade that most manufactures offer is called a Limited slip or Posi locker.

This means it either has a set of tapered gears or clutches to split and transfer the power more evenly to each wheel. So as long as both tires have some resistance they will both get power. But the Clutch type wears out over time. And if say a wheel is lifted off the ground due to say crossing a ditch. You will loose complete traction from the wheel left on the ground due to slipping. These are used a lot in drag racing and provide very good on road characteristics compared to full lockers.

Next upgrade is to what is called a locker. These are split into two groups. Your Lunch box locker (like the EZ locker or Loc-rite) and your Full lockers like the Full Detroit.

Lunch box

Full Locker (cable actuated Ox locker)
The Full lockers also come in several varieties. An automatic version which just sits inside the pumpkin and is always engaged or a selectable locker that you can control from inside the vehicle by either air, electric or a cable. But when engaged they all work the same.
They have a set of gears that lock together under spring tension. This spring allows for some differential in tire speed as you go around corners but creates a popping or clicking noise in the process. But if you are going in a straight line or do not create enough force to release the gear teeth. Both tires will spin at the same speed. Even if one of them is 3 foot in the air and the other under mud. This puts a LOT of tension on the axle shafts. Hence the development of the Selectable locker so you can disengage the locker and go back to an open or limited slip type setup. Very poor on road handle but great for off-road traction.

The last option I'm going to talk about is called a SPOOL.

This is similar to a Locker but does not release at all. This also comes in several varieties. A mini spool is like a lunch box locker. It goes inside of an open carrier in place of the spider gears. The difference is that it is milled out of one piece of metal. The full spool is similar except it is one piece of metal that replaces the whole carrier and is VERY strong. This is used a Lot in drag racing and off-roading because it permanently locks the wheels together. Now way without breaking to spin at different speeds. Note in most states it is illegal to drive these on public roads.

There is one more note I would like to make.
Some of the selectable lockers are not really lockers they are Selectable spools. What this means is that when they are engaged they take on all the properties of a spool but when released either act like an open or limited slip.
The ARB air locker is one of these. It acts like a Spool when engaged and an open when not engaged which makes it great to run on multi use rig or in a front axle where you want to be able to release the tension on the axle.

Okay this was the long version.
I am sure I missed a LOT of stuff but hopefully others can fill in the blanks.
Also this information is available all over the web. Pirate4x4 is a great source of knowledge for off-roading.

note pictures borrowed from Tellico4x4 and http://www.4wheeloffroad.com/.
"Nothing Free is ever Cheap." -Dion

"The Pleasure of what we enjoy is lost by wanting more." fortune cookie


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