Re: RE: Re: RE: Lockers
houdel said:
Any thoughts as to which performs better, Detroit Lockers or Air Lockers?
Yeah, lots of thoughts. Here's the basic's however.
Starting with a conventional differential, which is open, and requires both wheels to have traction. It sends rotation (not power) to each wheel. If one wheel wishes to move slower, it will send the extra rotation to the other wheel. Great on road, not so great off road. (Actually, just fine off road too, until you find a situation where one wheel on any axle looses a signifigant amount of tracton.
A locked differential would be just that, locked. No differentiation, the axles are locked together. You can do this by locking (welding or otherwise modifying) your differential, or by adding a "spool" which is pretty much just a solid block that holds the axle shafts together while providing a place to mount the ring gear. good off road, difficult to steer in front applications, tears stuff up driving on the street.
The Detroit locker (or others, I don't know which are available) has NO differential like above, but it's not truely "locked" so it's more streetable, however unlike a differential it will NEVER allow a wheel to stop unless the transmission stops. It is kind of an interlock that will always allow any axle (which is of course hooked to the wheel) to "freewheel" faster than the driveshaft input, however will NEVER allow any wheel to rotate slower than the driveshaft input. This prevents "dragging" tires in cornering and makes a "locked" vehicle much more streetable, easier to steer in the front, but it's downfall is that unless you're going perfectly straight, the second wheel won't start pulling until after the first one has "broken traction". In multiple axle applications, especially long ones, it takes quite a bit of sliding to get all the wheels to pull, and of course in heavy trucks the tires pull better before they slip, as opposed to trying to "chew" your way through anything.
And then there was the "air locker". Pretty simple in operation, IMO the best option, but pricey and not always as strong, and does require operator input. It is a conventional differential, however there is an added mechanism that when activated (by switched air pressure for an "air locker", or by electric or mechanical cable means), will stop the differential from differentiating, and "lock" the axles shafts (and wheels) on that axle together so that you have (most of) the best of both worlds
Of course, if you're not talking about standard half to one ton pickup axles, then everybody and their brother might not offer fifteen different options for what to do for extra traction, so availability and price might be a key deciding factor in adding these things.
If you've not been into one (or have but can't picture just how it all comes together), check out howstuffworks.com as they have a great animated picture of a differential in action. (search for "differential", they're all great information, but the first one (open differential) should be seen first. That makes the rest of the modified differentials much easier to follow.
