Posted by Nay on April 02, 01 at 14:53:58:
In Reply to: Still... posted by Marty on March 26, 01 at 15:03:05:
Read the quote - the wheels are locked except when you turn. That means the standard state of these units is locked, just like if you had a spool. As it says, neither wheel can spin. These units can simply allow differentiation by *unlocking*. And they can only unlock in coast mode.
I'm not trying to define a locker, I am just explaining how these things work. They do not activate under wheelspin. They do not allow wheelspin that is generated by torque going to the wheel with the least traction, and then lock up. They split torque 50/50. It is only by coasting that they allow differentiation, and coasting is by definition the absence of torque. When you stop coasting, the unit will lock again. If you get on the gas going around a corner, that thing will lock just like a spool, and it won't need one millimeter of slip to do it. Offroad, this can make tight corners difficult because it will want to go straight (what I have called "pushing"), often necessitating 3 point turns where none was required before.
I know a lot of people who are just putting spools in the rear axle because they like it better than the locking/unlocking mechanism of the automatic locker. It is simply more predictable even if it forces tire scrub around corners, and it will drive identically on the highway or in basically a straight line.
There is a lot of misrepresentation that goes on in this area by OEMs. Audi would have you believe that one axle cannot lose traction completely with their Torsen center diff, and this is simply untrue. With a Detroit locker, however, both wheels will turn at the same rate all the time unless you can coast. Put one in a front axle with a locked transfer case and you have a constant 4 way spit of power to the wheels, which is something Auburn, Eaton, and device that can allow slip, cannot do. This is why they are so popular with fourwheelers, and this is true fourwheel drive. The only other way to get it is with spools or manual lockers like ARB's, which are not lockers as much as selectable spools.
Nay
: I am troubled by your definition of a locker. Please explain the following quote from the Tractech website:
: "...They keep the wheels locked together (except when turning) so that together the left and right wheels always deliver maximum traction to the ground; neither wheel can spin out. They allow different wheel speeds in a turn by disconnecting the faster - moving wheel (usually the outside wheel which is ground - driven faster throughout the turn), driving the vehicle with the other (inside) wheel."
: Under your definition, the locker would enable the axle to be a spool anytime you were on the gas. This is not so. You must first lose traction, by whatever small degree of slip, for the locker to engage. The locker is classified as a no-slip because it engages within one revolution or less.
: >Nay wrote: I think you misread my post - I was not pitching the Detroit as a spool. The torque loaded state of an automatic locker is locked 50/50. It has to unlock to allow differentiation, which it does *only* in coast mode. It does not lock when it "detects" wheel slip; it unlocks when you let off the gas. I was responding to Andrew who stated that from the website he was looking at the Detroit would only engage when there was wheel slip. That is categorically incorrect. There is no such thing as wheel slip with a Detroit. The Detroit will allow differentiation in coast mode. You have to completely lose traction at both wheels to get wheel spin.