Why is 'hard' braking bad for fuel economy ?

[slurp812]

Originally Posted by Cd

So if I understand correctly, braking has no effect on FE. It is just the fact that you are wasting your momentum and having to rebuild it up again once you apply the brakes.

Just as I thought. ( Seems like common sense really )

To us it does! I watch so many people, with automatics ride each others bumpers, and brakes like crazy. It just drives me nuts! When I first realized that also, I thought of it as conserving momentum...

[guudasitgets]

Dale Jarrett commentating in the ESPN booth at the Bristol NASCAR race in 2007; "The biggest fuel waste is that pedal right in the middle"

[SilverCrown9701]

As a Hypermiler, you want to learn to "drive without brakes"...meaning use just enough acceleration and coasting to get you between stops on your destination. If you have to constantly brake hard between starting and stopping then you are over accelerating and under coasting.

However, "hard braking" has its place. The entire basis of hypermiling is to maintain as much momentum as possible. Let's say you are driving 45 MPH and the light ahead is still green...then all of a sudden, it changes to red. You quit accelerating and begin coasting but you realize that you're still going too fast and will have to stop ahead. INSTEAD, you can "brake hard" with a few hard brake pulses, reducing your speed to 25-30 MPH. You can extend your coasting time and hopefully make it through the light.

It takes much less energy to accelerate from a few MPH versus a dead stop. You also have to keep in mind your SAFETY and the wear and tear on your vehicle.

Braking hard and taking sharp turns at higher speeds increases wear on your suspension, tires and brakes. It also causes the gasoline to splash around inside your tank, which can offset your numbers.

All of this takes patience, timing and practice but once you master them then you will be that much better a driver.

Remember...NEVER ever risk your safety or your vehicle for a couple more MPGs. Your life is much more valuable than fuel economy.

[gone-ot]

Think about the following events that occur when BRAKE is pressed:

• DISTANCE coasting is reduced.
• TIME engine not loaded is reduced.
• MOMEMTUM is being converted into HEAT (by brakes).

[SilverCrown9701]

Originally Posted by Old Tele man

Think about the following events that occur when BRAKE is pressed:

• DISTANCE coasting is reduced.
• TIME engine not loaded is reduced.
• MOMEMTUM is being converted into HEAT (by brakes).

I completely agree. Momentum should always be the first on a hypermiler's list. The less you have to stop, the more efficient your results. My only point was when faced in a particular certain situation, never compromise safety or the well being of your vehicle for fuel economy.

Keeping this in mind will make you a more conscious and efficient driver by ensuring that you take the additional care to give yourself plenty of space, time and patience.

[XYZ]

Originally Posted by SilverCrown9701

I completely agree. Momentum should always be the first on a hypermiler's list. The less you have to stop, the more efficient your results. My only point was when faced in a particular certain situation, never compromise safety or the well being of your vehicle for fuel economy.

Keeping this in mind will make you a more conscious and efficient driver by ensuring that you take the additional care to give yourself plenty of space, time and patience.

A Q&A:

Why is hard braking bad?

Because it stresses and degrades your brake drums and shoes and/or disc pads and rotors faster than soft braking does. Your brakes will wear faster and that sucks $$$ out of your pocket faster. So don't make a habit of doing it.

Some of us here are only interested in saving fuel, at any cost. Some of us are primarily interested in saving $$$. Some are interested in both. It's your car, your money, and your choice.

Is all braking bad?

As others have said, all braking does is that it simply reduces momentum. A hypermiler's wet dream would be never to have to brake at all. But that's a fantasy - it's not real life in the real world. So let's be realistic and compare braking to '"when nature calls": when you gotta go, you gotta go. And when when you gotta stop (immediately, as in emergency situations) stopping is much better than NOT stopping.

[Xist]

Metro mentioned the numbers game. When I drove Bacon, if I needed to stop while on a road trip, I shifted to neutral and waited it out, but when my Ultragauge showed GPH below my overall goal, I came to a stop and turned off the engine. It has an automatic transmission, so EOC was not an option. It was frustrating because I wanted to use the last of my momentum, but it just did not seem worth the fuel used while idling.