Lockers? Well thinking about them..but? - Off-Road Forums & Discussion Groups
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post #1 of (permalink) Old 06-19-2002, 08:55 PM
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Lockers? Well thinking about them..but?

What the hell are they LOL.. sorry, I aint never done anything like it, i know what locking hubs are, but what are lockers? How expensive? with they go with IFS?
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post #2 of (permalink) Old 06-20-2002, 01:55 AM
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Re: Lockers? Well thinking about them..but?

In a nut shell, most stock axles use what is called an "open" differential. This refers to the gears inside the big round part at the center of the axle housing. With "open" diffs, when you hit the pedal, only one wheel gets the power and spins. It can be either wheel at different times while driving. This setup is used so that the wheels will turn smoothly at different speeds while cornering. A locker replaces the "open" gears with a new unit that literaly locks the two axles (wheels) together so when you hit the gas, both wheels turn. Presto!, twice the traction while off-road. The down side is often clunking on turns, uneven tire wear because one tire always drags around corners and different driving characteristics. Most people get used to these quickly.
post #3 of (permalink) Old 06-20-2002, 01:12 PM
 
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Re: Lockers? Well thinking about them..but?

<font face="Comic Sans MS">Lockers are devices that mechanically lock both shafts together in an axle in order to transfer power *equally* to both tires on that axle.

Limited slip has a system of clutch packs that transfers some of the power to both axles, although is in my opinion nearly worthless. If you ever lift a tire chances are a limited slip will *not* cut it.

Open differential, 100% of the power just goes to whichever tire has least traction. This can get you stuck...

If you drive frequently on ice or snow you *will not* want a front locker and "might" not want a rear locker. Front you can just forget about for any somewhat slick surface where you'd need 4wd, it'll cause you to push right thru intersections if the clutch is not depressed or tranny in neutral (the wheels will slip, rear will then propel forward)... Not good for turning on most surfaces and since we do not have lockable hubs it's not all that great anyhow...</font>
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post #4 of (permalink) Old 06-20-2002, 05:57 PM
 
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Re: Lockers? Well thinking about them..but?

Not exactly correct.....In a stock open differential axle, the power is divided in inverse proportion to the traction at each tire, meaning that the tire with the most "slip" will receive that amout of power proportionly. If it were true that any difference in traction shifts ALL the power to the slipping wheel, then a normal rear drive axle would slip in every turning situation and the car would never be able to turn. Unfortunately, an open differential cannot tell the difference between a turn and a loss of complete traction at one or other of the tires. The way the system works is that the slipping/spinning tire
gets all the power and the one with traction just sits there with none. Sometimes you are able to "fool" a slipping open axle by applying the parking brake to simulate traction to the slipping tire and get the tire with traction some power.

This is true for any stock 4x4 with 2 open axles. The explanation gets a bit more complicated when you start to consider how power is distributed by the transfer case. Transfercases can also be "open" or "locked".

"Lockers" and "Limited Slip" differentials minimize this trouble inherent in open axles.[img]images/icons/smile.gif[/img]
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post #5 of (permalink) Old 06-20-2002, 06:36 PM
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Re: Lockers? Well thinking about them..but?

so really a locker is a no go? Or well worth it?!
post #6 of (permalink) Old 06-20-2002, 06:50 PM
 
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Re: Lockers? Well thinking about them..but?

Well, that depends on what level of off road driving you want to do. If you are just starting out, then you can probably learn how to drive your Jimmy off road in stock form first. If you don't go to extreme, then the 4wd part time with open differential axles would do just fine. I've driven my 1986 Jeep Cherokee XJ that way for 16 years now.

Later on, if you wish to get into rock crawling or something where you will definitely be lifting tires off the ground, then a locker will be essential for your truck. Good Luck!![img]images/icons/smile.gif[/img]
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post #7 of (permalink) Old 06-20-2002, 08:03 PM
 
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Re: Lockers? Well thinking about them..but?

<font face="Comic Sans MS">I don't quite see why this: <blockquote><font class="small">In reply to:</font><hr>

If it were true that any difference in traction shifts ALL the power to the slipping wheel, then a normal rear drive axle would slip in every turning situation and the car would never be able to turn. Unfortunately, an open differential cannot tell the difference between a turn and a loss of complete traction at one or other of the tires. The way the system works is that the slipping/spinning tire
gets all the power and the one with traction just sits there with none.

<hr></blockquote> differs from what I had said above.

If you ponder it, the outside wheel is the one that goes faster, therefore that would be "seen" as the differential as being the wheel that's slipping. We know the outside wheel *must* be the one that's moving faster since it has to cover a larger radius on the arc... Therefore it's easy to see how you can turn... Since one wheel still gets the power to propel the vehicle...

And essentially unless traction is similar on both wheels, you can get away with saying all power goes to the side with no traction...


As to whether a locker is worth it, tell us what the heck you're planning to do with it and we'll tell you our opinion on the matter... Bottom line is if you've gotten by without it, chances are you will not need it... As a generalization... But if you're pushing against the limits of the differential type you have now (open) then you're better off upgrading... </font>
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post #8 of (permalink) Old 06-21-2002, 09:46 PM
 
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Re: Lockers? Well thinking about them..but?

Well, Tim, not to put too fine a point on it, you posted that the wheel with the least traction gets 100% of the power in your first post reply. This is true when one wheel has zero traction. When one wheel has lets say 20% more traction than the other, the one with the less traction gets more power, to be sure, but the high traction one still receives some power. In the turn, the outside wheel gets more but the inside gets some, not none.

Where both tires have no traction, then both will get 50% of the available power to the axle because the differential only reacts to the relative resistance between the two wheels. Since both are zero (in this case) each tire receives an equal amount of power, just as they would if the vehicle were traveling straight down the road with a good grip in each tire. This is the reason that 4wd part time high can be dangerous on icy roads; the zero traction in each tire of the axle will cause each to spin equally and that will cause the rear (or front) of the vehicle to slide sideways. This is also true of a fully locked driveline, namely a locker and a locked up transfercase. This is why a center open transfercase (full time 4wd) is safer to drive on icy surfaces and a fully open system (t'case plus axles) are best for safe icy travel.[img]images/icons/smile.gif[/img]
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