To coast or not to coast

[FullSack]

So I have something that's really been irritating me. My father-in-law (great guy, not the typical FIL) like to "coast" when driving. If there is a slight down hill grade - even for a 1/4 mile - he slips it into neutral and coasts until the truck starts to slow down. He give it a little gas to bump up the RPMs and then slips it back into drive. :{



He's driving a Excursion with a stroker for what it's worth.



There's more. If he's coming to a stop light. You got it, slips it into neutral and lets the truck coast all the way until he needs to put the brakes on. Every time I drive with him, I have my eyes on the side mirrors expecting ****** off people swerving around us because the coasting can get below the speed limit. It's extremely annoying, but . . .



is there any damage that can occur as a result of this? My biggest concern was slipping the transmission back into gear. Your thoughts?

 

[Hoefler]

You might check your local laws, in most areas, it is not only illegal, it is dangerous. For reasons like you mentioned, the need to accelerate suddenly, you could also set the vehicle into a slide or spin.

 

[keimmmo]

I am not fanitical about it, but I do the same if not in a hurry. It saves fuel. I always try to avoid causing problems in traffic. Most of the time when I do it, I have the road to myself.



I do not believe it damages anything. I have been doing so since before buying either of my Dodge diesels. Both trucks are fairly high milers and have never had any trans problems. I also frequently downshift to engine brake.



Steve Keim

 

[Cummins Pilot]

When I drive rear wheel drive vehicles on ice with an auto I knock into neutral so there isn't any forward force on the wheels. You'd be surprised how much of a difference this can make sometimes when slowing down.



My truck is a stick & I coast all the time. I'd rather replace brakes than to wear out the entire drive train faster. If I'm towing its always in a gear though. As for it being more dangerous I disagree. Someone in FL might argue that driving on ice is dangerous when us in AK do it all the time. Plus I can hit a gear just as fast as it takes an auto to spool up and pull when it is in gear but out of the throttle and at idle.



Commercial trucks must always remain in gear due to regs. I have never heard of that for personal vehicles. And how would you prove that anyways????

 

[WBusa]

Coasting in neutral whenever possible has been the accepted norm among many European drivers for generations. Done properly, it saves fuel.



In my manual transmission vehicles I coast when I can, but "when I can" means when it is not particularly unsafe to do so... for example, when nobody's behind me and the road is dry and visibility is excellent. Also, in my gassers I won't coast downhill if doing so would require me to use my brakes a lot to maintain speed.



As has already been noted, coasting could in principle be unsafe if an emergency situation required a burst of power, so one has to use one's head. Also, pretty much every state's laws require the driver to be in "full control" of the vehicle at all times, and a cop can interpret coasting in neutral to be a lack of full control. I've never heard of anyone getting popped for it, but if you were in an accident and they found your wrecked car's transmission in neutral, you'd prolly hear about it.



In my auto-transmission Dodge CTD, I certainly do a lot of takin' my foot off the go-pedal as early and often as I can. That's a different kettle of fish entirely. When I first got the Dodge I had to train myself to drive further ahead of my nose than I used to, originally because the truck is heavier than what I was used to driving, so requires more stopping distance, but ultimately because I just hate roaring up to a light that changes in front of me, requiring me to slam on the brakes and dump all that momentum I just paid for.

 

[DragonflyDriver]

Don't have any automatics but I am an avid coaster. Got where I don't give a hoot what anybody thinks that is behind me, especially when the light ahead is red. Can never recall needing to accelerate to get out of a situation (haven't robbed a bank) but I'm sure it happens. If it happens frequently then the problem may be "you".

 

[DiTrani]

Most diesels don't fuel the engine at all when over-running (e. g. coasting down a hill in gear), so if you have to use the brake to slow down when coasting in neutral, you are probably using more fuel than coasting in gear.

 

[JFaulkner]

Saves fuel?? WTH! That has to be one of the biggest long shots I've ever heard! That's like saying you could see a noticeable difference in fuel economy by washing your truck! (sure you did) Theoretically yes, in the real world no! A good gust of wind would eat that up. I'd be willing to bet that the same people who "Coast to save fuel" are the same people who find it absolutely mandatory to let their truck idle and burn fuel for 3 minutes to let the turbo cool 30 more degrees.

I don't give a hoot what anybody thinks that is behind me

That my friend unfortunately is the perfect recipe for a good road rage beating. (not that I would ever condone such a thing ) If I can tell that the person behind me is in a hurry (for whatever reason) and I'm not (which never is the case) I'll at least try not to do anything dumb like not paying attention at a redlight and being a little slow on the draw. It's called "courtesy". Is "urinating" everyone off behind you at every stoplight worth the $. 00004 you'd spend extra to actually step on the brake rather than be continuously slowing down for a 1/8 of a mile? If it is I'd like to offer a piece of advice, stay off all state hwy's. Stick to the backroads, please. Some people do have things to do and places to be and the cost of being late or time lost being stuck at that redlight because you didn't want to have use the brakes, could be just enough to push some over the edge, like it or not.

 

[klenger]

I do it all the time (well not exactly all the time), but it's easy to do with a manual trans. I think it's one of the reasons that I can get 21 MPG around town.

 

[DragonflyDriver]

Saves fuel?? WTH! That has to be one of the biggest long shots I've ever heard! That's like saying you could see a noticeable difference in fuel economy by washing your truck! (sure you did) Theoretically yes, in the real world no! A good gust of wind would eat that up. I'd be willing to bet that the same people who "Coast to save fuel" are the same people who find it absolutely mandatory to let their truck idle and burn fuel for 3 minutes to let the turbo cool 30 more degrees.



Quote:

I don't give a hoot what anybody thinks that is behind me



That my friend unfortunately is the perfect recipe for a good road rage beating. (not that I would ever condone such a thing ) If I can tell that the person behind me is in a hurry (for whatever reason) and I'm not (which never is the case) I'll at least try not to do anything dumb like not paying attention at a redlight and being a little slow on the draw. It's called "courtesy". Is "urinating" everyone off behind you at every stoplight worth the $. 00004 you'd spend extra to actually step on the brake rather than be continuously slowing down for a 1/8 of a mile? If it is I'd like to offer a piece of advice, stay off all state hwy's. Stick to the backroads, please. Some people do have things to do and places to be and the cost of being late or time lost being stuck at that redlight because you didn't want to have use the brakes, could be just enough to push some over the edge, like it or not.

Dang, ain't you the jumper to conclusions! Who said I was slow off the light?

But it is nice to finally "meet" one of the dumbarses that perform maximum braking to every red light. You friend, are in a hurry to go nowhere! You also probably never notice how drivers like myself pass your *** when the light is once again green! Learn to look beyond the bumper in front of you. Chances are, it's not the guy in front of you that is slowing you down, it's the traffic light. So when you punch it to get around me and then slam on your brakes, do you really feel like you made a good move? These questions are rhetorical cause you won't ever understand it. From horses, to motorcycles, to trucks, and aircraft, I know when speed will get you somewhere and when it is better to just be patient and "wait it out". Unless you have a flashing light on your vehicle, you're gonna sit at the light like everybody else.

 

[EKlem]

I am a believer in proper coasting when driving a manual transmission vehicle. Putting the truck in neutral then braking hard doesn't make any sense at all. You may as well spin the engine with the kinetic energy of the vehicle rather than turn that kinetic energy into heat with the brakes. However, if coasting would mean that you didn't have to apply fuel to maintain a given speed, it should be employed(obviously keeping in mind that it must be safe to do so).



Coasting is just one of the things done by people who think about how they are driving and are trying to maximize their fuel economy. Bigger differences can be made by properly anticipating stop lights so that you don't fuel right up to the point where you have to brake hard. Another big one is how fast you accelerate. F=ma, so the harder you accelerate, the worse the mileage is. As far as I am concerned, coasting is great when done properly.



One thing that is often overlooked in fuel economy debates is your action's effects on others. To absolutely maximize your own economy, it would hurt others. You must make a decision as to whether you are trying to help the environment or just your pocket. If the answer is the environment, remember that sometimes accelerating a little harder may save 20 cars from having to brake real hard and waste a lot of energy.

 

[Cummins Pilot]

JFaulkner, what difference does it make if I see a light turning red up ahead and I knock it out of gear to begin slowing down? Not only do I stop using fuel to maintain speed I'm also bleeding off speed which will save brakes instead of maintaining speed until I absolutley need to brake. I'm not in a race where I'm trying to drive it in deep. We still arrive at the light and stop. We haven't lost anytime. And a lot of times I cost down knowing the light will go green and people like you that went by, got to the light & stopped are sitting dead still as it goes green and I'm still doing 20mph. I'll wave as I go by. If your the retard that passed by me and got in my lane and IS STOPPED at the light as it goes green and I have to slow because of you I get irritated. So lets recap. I stop maintaining speed sooner (fuel & brakes saved), I still have some rolling speed when the light goes green so I don't have to accelerate as much nor did I have to stop the truck. Hmmm more fuel and brakes saved. I've got places to be also, your not the only one.

 

[ezcurra]

I only drive sticks. I'm a believer in always being in gear and to use the engine to slow down when needed. Having the truck in gear makes the engine act as brake anti-lock device, and makes decelerations much more progressive and controllable. Also, if you are in neutral and the engine dies, you lose power steering and power brakes. Usually not a good thing. So no coasting in neutral for me

 

[PKozlowski]

Dang, ain't you the jumper to conclusions! Who said I was slow off the light?

But it is nice to finally "meet" one of the dumbarses that perform maximum braking to every red light. You friend, are in a hurry to go nowhere! You also probably never notice how drivers like myself pass your *** when the light is once again green! Learn to look beyond the bumper in front of you. Chances are, it's not the guy in front of you that is slowing you down, it's the traffic light. So when you punch it to get around me and then slam on your brakes, do you really feel like you made a good move? These questions are rhetorical cause you won't ever understand it. From horses, to motorcycles, to trucks, and aircraft, I know when speed will get you somewhere and when it is better to just be patient and "wait it out". Unless you have a flashing light on your vehicle, you're gonna sit at the light like everybody else.

I have to agree, it's so funny how the people in the Big Hurry, cutting people off and causing wrecks etc. You always catch right back up to them but

THEY THINK they're getting somewhere. If they paid just a little more attention they'd see they're not getting anywhere any faster.

and is that 4 seconds you saved worth it?

Yippee. you got one parking spot in front of me.

I just laugh and get in they're way as much as I possibly can. (not)

 

[PKozlowski]

Another thing that is funny is the speed limit is the same speed

in all the lanes. It's not 95 in the left and 75 in the right.



Chill out. Relax. What are you in such a hurry for anyway? LOL!

:-laf



(this should really start a war)

 

[WDaniels]

I'm not saying anyone is wrong or flaming anyone but ezcurra and Hoefler are right. It is illegel to drive a vehicle if it is not in gear. If the shifter is in gear but you have the clutch pushed in and are coasting, the law considers it out of gear. That is because there is no transfer of power through the power train to the drive wheels. And when there is no power to the drive wheels, you are not fully in control of you vehicle. Now I can see a bunch of you guys gritting your teeth and getting to jump all over my can, But wait a second, I speak from experience(thusly said... . "Almost got a ticket for doing it but squeeked, and I mean squeeked by with a warning instead")

WD

 

[PKozlowski]

I do think if we all read the books that it's illegal for any vehicle to

"coast". Probably in all states and not just the big trucks.

Have to agree with you.

 

[JFaulkner]

If the light is already red I don't have a problem with you coasting. It's the moroons that start slowing down (like I said) an 1/8 of a mile before the intersection in anticipation of a red light just to save brakes. If you want to save brakes that bad stay home!



I started my rant with the BS statement of "fuel savings". If any of you actually believe that coasting to a stoplight vs leaving it in gear is going to show ANY fuel savings then you are dillusional at best!

Dang, ain't you the jumper to conclusions! Who said I was slow off the light?

Maybe YOU should re-read what I wrote again! I didn't say YOU were slow off the light. I said "I'll at least try not to do anything dumb like not paying attention at a redlight and being a little slow on the draw. " For example, there are a few lights around here (turn lanes) that only let about 4 or 5 cars through, UNLESS the guy at the front is asleep (or dreaming up another "snake oil" way to save fuel :-laf ) then only about 3 can make it and the next 5 have to run the red or wait about 3. 5 minutes for another chance.

But then again these statements are rhetorical and you won't ever understand them. :-laf

Another thing that is funny is the speed limit is the same speed in all the lanes. It's not 95 in the left and 75 in the right.

It's been determined that the safest speed is the average speed of traffic, reguardless of what that may be. (if you don't believe me drive 50 in a 75 and see how many accidents you cause)

 

[PKozlowski]

Have to agree with you.

 

[rbattelle]

I'm a believer in always being in gear and to use the engine to slow down when needed. Having the truck in gear makes the engine act as brake anti-lock device, and makes decelerations much more progressive and controllable. So no coasting in neutral for me

Me too. It's pretty rare that I coast in neutral. In my opinion, it's more efficient to compression brake (saves fuel and service brakes), especially downhill.



Ryan