OKoffroad.com — 4x4 Editorial|
Is Parallel Power Really Easier?|
by Bill Burke |
reprinted with permission
Although both my D-90 and my Range Rover have lockers, I want
those that I am training to understand how to drive without using, or actually getting used to,
lockers. Granted ARB lockers are great; switch them on whenever you need them and the rest of the
time they are off!
I have always taught that it's best to learn how to negotiate the terrain without lockers so
you get the finesse of 4-wheeling down.
Understand the dynamics of the vehicle and its handling characteristics on- and off-highway, then
start to add the goodies. Yes, I own Air Lockers now but I cut my teeth on posi-traction and
Detroit Lockers. Try driving Detroit's front and rear with 35's and no power steering!
While you negotiate rough terrain, the suspension and your "line" will not always allow you to
have smooth contact with the ground. At some point, the tire will catch air or lose full
proximity with the ground, causing the tire to spin. Remember Murphy's Law, the tire with the
least amount of traction gets the most amount of power. You will hit moguls, come off rock ledges
with two tires and attempt hills with very loose soil. This is where lockers really come in handy.
Once you've purchased a set of lockers and had them installed, here is a short course on how and
when to use them. Whether you have air, electric or mechanical lockers, limited slip,
posi-traction or whatever, the techniques are generally the same.
First: be careful on side angled (off-camber) hill sides; i.e., the vehicle is traveling
on a side slope. If it is mucky, icy, snowy or any other type of slippery-slidey side slopey
slope, use open diff, if possible. Lockers will tend to "walk" you sideways down slope. This is
because both wheels are rotating at the same speed. If one wheel is "static" and the other is
rotating, the static one will act as an anchor or stabilizer that will keep the rig from
slipping sideways. When on these side slopes, let the vehicle idle across, giving the tires a
chance to dig in and get the best traction.
Second: when going up hills or any incline, aim straight up. The weight shift to the rear
will give you added traction so the locker in the rear is advantageous. WATCH OUT for the front
end, though! The tires will have a tendency to catch ledges and occasionally loose soil and
"walk" the front end around either left or right, causing the rig to get sideways on a hill. Then
if you PANIC, give it gas, and don't come out of lock, you could roll over.
I usually get lined up for the ascent, approach cautiously, engage the rear locker and start the
climb. Depending on the terrain, rock ledges, sand, loose granite, mud, etc., I will then engage
the front locker once I feel control of the steering and front end traction have been attained
(gut feeling!). About halfway up the incline, I'll engage the front locker. If you don't have air
lockers, be careful of the front end walking! No matter how hard you try to steer, with the front
end being light due to gravity pushing on the rear, you MUST modulate the throttle carefully.
Remember, minimal tire spin. Soft tires (low pressure) helps here.
reprinted with permission
Third: when going downhill, be careful that the rear end does not swing around and meet
you in front! I like using both front and rear when going down hill. It allows all tires to have
traction, resisting the "breakaway" feeling. Engine braking is very important here and having all
four tires helping makes a big difference. Sometimes when in open-diff rigs going downhill, the
two tires (1 front, 1 rear) that are holding the rig back, hit loose soil or get air, allowing
the rig to "lurch" forward--I call this the "lurch effect"--and it'll scare the heck out of you.
Sometimes light pressure on the brake pedal will work, but I don't like using the brakes on the
trail unless absolutely needed. Using engine compression with lockers is most advantageous 'cause
all 4 tires are adding traction and resistance.
Fourth: steering is hard to do especially on hard surfaces like slick-rock, granite faces
and boulder outcrops. When you are on a "bind" (no not binge!), the lockers will hinder your turn.
You need to disengage the front end (ARB) and "bump" the throttle to allow slack in the gears to
disengage the lockers. With mechanical, you need to play the throttle softly to allow the turn.
Sometimes when I come out of an obstacle, the rear end will "steer" me straight even if the front
is unlocked. So, if I can I will disengage (ARB) the rear as well. The Detroits will clank and
bang, the Lock-Right will click and clack, but it's the best you can do. When I did have
mechanical lockers, I would run the front end unlocked, the hubs free, in 4WD low using only the
rear end and the mechanical locker in the rear. Then when I needed to "get to it," I would lock
the hubs in! In mud and soft dirt/sand, the rear locker will steer you straight, even though you
are turning the front tires! Again, throttle steer using some of the finesse at the foot. Let the
tires slow down, then blip the throttle to "pull" the front end around.
Note: Air lockers can be engaged anytime they're needed. Just don't be spinning the tires.
Engage them moving or not; disengage them anytime, but you need a moment of slack to make sure
they unlock. Having lockers means you need to pay more attention to the vehicle and its handling
characteristics. Add big tires aired down to 12 psi and it takes some finesse to make turns and
keep the vehicle aligned. Driven responsibly, lockers are a great help. They actually reduce
environmental abuse due to all four tires helping, not just two spinning.
Bill Burke's 4-Wheeling America
Fourwheeling for me: "Having the ability and skill to venture from the paved corridors
using primitive roads and 2-tracks to explore the world that is seldom seen and see nature at its
(Thank you from OKoffroad.com)
Fourwheeling for me:
"Fun friends & four wheel drives - who could ask for more."
Fourwheeling for me:
"My escape from the working world, all the stress from the rest of life, thank goodness for