Do you believe coasting in neutral (in a manual transmission) is safe?

If NO - why not? The only answers I've heard is - "because it isn't" and "it can pop back into gear"...

 

I dont see why it would be unsafe. If it did pop back into gear it would grind, thats it. Unless youre holding it in a gear while its grinding it wont go back in.

Only reason why I wouldnt do it is because its a waste of gas. You save more gas when slowing in gear. Its also less ware on brake components.

 

how would keeping it in gear save more gas? seems like the higher revs would use more gas...?

 

There is absolutely no way a modern syncromesh transmission can go into gear by itself ever. There are mechanical detents that prevent movement without physical intervention and the blocking rings of the syncros also prevent movement because of their interference fit on the FORCING cone on the gear set that's why it's called the forcing cone it needs force to move because the blocking ring is being FORCED onto it's surface.

There is no mechanical harm done to the transmission or any other part of the vehicle.

That being said it is illegal in most state. Either outrightly or as an element of reckless driving statute in some states. The reason it is banned is that you loose engine braking while in neutral. The laws were first legislated way back in the old days because in the real old cars you could go faster coasting in neutral than with the engine engaged and the greater speeds achieved over ran the ability of the old mechanical brakes to stop the car at those higher speeds BUT the bottom line is the laws haven't been repealed and are still enforced. The other problem is liability if you crash going down hill in neutral for no explainable reason the insurance company can apportion blame and the onus would be on you to prove a valid reason why you were in neutral and violating the law.

 

i dont see how it is super unsafe... prolly not the smartest idea... but hell your not gonna do ne damage to ur car (unless u dont brake and u hit something) i just leave it in gear to get engine braking dont see a reason not to leave it in gear.

 

The only time more gas is injected is when you press the gas pedal. Read up on wiki on how it works: Engine braking - Wikipedia, the free encyclopedia - Friction from the road is causing the RPMs to increase, so more fuel is not injected during these higher revs unless you gas it.

 

When slowing down IN GEAR the throttle is closed. This tells the ECU to throw almost NO fuel; therefore saving gas. Down shifting actually saves gas when you do not rev match. However dragging the clutch to downshift to the next gear eats the clutch slightly. I still do it....

I have a wideband o2 on my Mx-6. I will tell you slowing down in gear the gauge goes blank. Thats leaner than 17.0 AFR's, thats damn lean.

 

Whether it is safe or not depends on the speed you are going. I have never coasted in neutral with my Fit, but I used to do it on a nightly basis on one particular stretch of road with my previous vehicle, while driving home from work (around 2 AM). The road was a freeway offramp about 1/3 mile long, level ground, at the end of which was a traffic signal that would remain red until a vehicle tripped it's sensors. That was totally safe in neutral, because my car did not accelerate; however, I would never even think of having it in neutral while descending a steep hill. That would be totally unsafe .

 

how would that be unsafe?

i think most of you are a bunch of pussy's if you think coasting is dangerous....or, at minimum YOU'RE that bad of a driver that it is.

just like sitting at a stop light in gear....WAAAAAAAAAAAA they say you're in danger of a car hitting you from behind while stopped....um...if a car's coming up at you and you ARE in gear...and you react by dumping the clutch and stomping the gas (you would...i would...it's NATURAL human instict to do that) you're just gonna bog teh car, kill it, and also be in gear so the impact will worsen.

this is a stupid argument

/thread

 

Not a stupid argument to the guy who posted the first question...

I often coast in neutral when there's a red light ahead or a stop sign, if there's nobody behind me.

It means I can stop pumping in gas earlier because there's no engine braking so I can coast farther than if decelerating. I also coast into my parking spot in front of my house, easy covering 100+ metres in glide mode and I have it timed perfect that I hardly need to touch the brake.

Nothing wrong with it.

Who mentioned coasting downhill? That's a good point against coasting, because you lose engine braking, but other than that there's no real downside.

Coasting with the engine off, that's another matter, as well!

EDIT: As for the "not leaving it in neutral at a traffic light" the reason was that if you are the first and only car stopped at the lights, and somebody bumps you from behind, they would push you into the stream of traffic that is zooming across your nose on their green.

However, I agree it's a pretty narrow application and not much to worry about.

 

I voted that its not safe, but I do it myself. For me the reason why its not that clever to do it, especially in traffic is because if there is a sudden situation that you need to get yourself out of ie. accelerate past someone, or around someone/something to avoid getting hit/hitting someone, I dont think your reflexes are fast enough to quickly snap it back into gear (first to assess which gear would be best for the speed that you are doing) and then swerve. Hope that makes sense.

 

Agreed, if it's a manual, use the engine compression as a brake, just be carefull when you downshift and don't over-rev the little guy.

but I see Suzi's POV too.

 

I think your rude and need to grow up,,,,,,,,
The reason you put a MT in nuetral at a stop is to save the throw-out bearing,,,
To add to the debate,,,
The reason you don't coast is,,, it's illegal and your not in complete control of your car when coasting,,,( if your found at an accident that kills someone, and you were in nuetral coasting your prolly facing manslaughter charges)
That said we prolly all do it , myself included,,but you need to use common sense. Coasting to a red light or into your driveway would seem OK as stated above,,,Coasting a steep hill is moronic and dangerous,,,,
So it's a complex answer to your question,,,not just a yes or no,,,I voted to not do it (but I do sometimes),,,,,
read more here,,
https://www.fitfreak.net/forums/eco-...low-15mpg.html

 

Agreed. That's an ad hominem attack. (Insulting the person, as opposed to the argument.)

It's akin to the following:

Person 1: "Global warming has no real sound scientific basis, as per the following sources..."
Person 2: "Yes it does! You're a poo-poo head!"

Person 2 did an ad hominem attack. It's not polite, and it certainly doesn't make sense.

 

Those are the times I do it as well. As far as selecting a gear quickly if I need to GO... it's easy. I am always, in the back of my mind, paying attention to my speed so I know which gear I would need to go into for good power output without over-revving the engine. It's just all about knowing the max speed for each gear.

 

Coasting is safe I do it fairly often, ONE exception on the safety issue.

I wouldnt coast down a long steep hill that required me to be on the brakes quite a bit to keep the speed fairly legal. Why? Because hot brakes fade (boiling the brake fluid) and you could burn up the pads even.

 

It's safe. I've done it in all my cars. I don't do it in the automatics, though I believe they now have electronic lockouts to keep you from engaging reverse!

The throttle closing doesn't make any sense to me. When I glide, the car is at idle. That's the minimum amount of gas it's going to use just to stay running...

 

I think this comes down to what is the definition of safe is?

Generally speaking I don't see a lot of harm in coasting, however the ability to gear down gives you considerably more control over just mushing the brake to stop. It also means your brakes are working less hard and therefore less prone to brake fade from heating up too much.

So back to the first question; if you definition of safe is not flying out of control and crashing as a direct result... then coasting is safe.

However if your definition of safe is more preventative then really the safest way to drive your car is by gearing down to stop and remaining in gear at highway speeds.

Personally I would sooner people go after the a$$hole on his cell phone all the time than even bother with somebody who is coasting.

 

I can't think of any reason that it is unsafe! That's the way I was told to drive back in drivers education. This was over ten years ago. So maybe stuff has changed?

 

I can't think of any reason that it is unsafe! That's the way I was told to drive back in drivers education. This was over ten years ago. So maybe stuff has changed?