Left-foot braking is the act of using your left foot on the brake pedal, while simultaneously using your right foot on the throttle. Left-foot braking is a finesse skill to use in four-wheeling, specifically in 4wd low range circumstances and especially if you drive an automatic transmission.[Not a valid template]
Application and practicality issues vary by make of vehicle, and can be detrimental to weaker-axle vehicles or vehicles with disproportionate quantities of torque. Therefore, I will speak to left-foot braking as it pertains to Jeeps and their fabulously tough front ends.
Left-foot braking can give you some finesse over obstacles, reducing both the chance of banging undercarriage as well as the amount of stress on your passengers. If you are traversing a rocky outcropping, you are most likely applying some power to climb over it. No matter how careful and nimble you are, as your center of gravity crests the apex of the hill, gravity will want to make you lurch down the other side in that brief moment it takes to move your right foot from the throttle to the brake. If your left foot is already there, there is no delay and no lurching. What’s wrong with lurching, you ask?
First, ask your passengers what style of ride they prefer. Then ask your Jeep. Left-foot braking reduces the momentum that compresses the suspension, causing not only extra wear on suspension components, but also damage to expensive undercarriage parts when they get smacked on rocks.
Left-foot braking can reduce roll back and increase control on gnarly climbs. Do you make every hill climb you attempt the first time? Me neither, but it sure is a lot more comforting to have the control of stopping the Jeep before it starts to roll back. For those of you driving rear drum brakes, it is especially important to not get any rollback momentum started as hitting the brakes after momentum has started usually results in a slide.
Left foot braking can also give you a traction advantage when wheels start spinning. Sure, those of us with the Axle Lock feature, standard on all Rubicons, can just hit that “get out of jail free” button, but if the situation is moderate or we don’t have the luxury of axle lock differentials (a.k.a. “lockers”), we can still affect a “posi-“ or “limited slip” action by using left-foot braking. With open differentials, the power transfers to the tire with the least resistance, meaning your power is NOT going to the tires that actually have the most traction. By applying the brakes with your left foot, then slowly building up some throttle with your right foot, you are creating resistance to the spinning tire, thereby getting some power to transfer to the other wheel that actually has traction. It may not be much, but it can be enough to get you moving again.
The Traction Control System (“TCS”) on 2007 and newer “JK” Wranglers exhibits limited-slip characteristics by utilizing the ABS brake system to automatically apply brakes to the spinning wheel and effect some power transfer to the wheel with good traction. With vehicles equipped with limited slip “Trac-Loc” differentials or TCS, some good left-foot braking by the driver can actually effect better traction than the Jeep will by itself (though the 2011 and newer Wranglers have an improved TCS that often outperforms the left-foot braking capabilities of most drivers).