View Poll Results: Is it safe to coast in neutral in a MT?
Yes - it's safe
95
76.61%
No - it's unsafe
15
12.10%
I really don't have a clue
14
11.29%
Voters: 124. You may not vote on this poll
MT - Coasting in Neutral Safe?
#61
08-06-2008, 04:47 PM
Ok, Ok.
In the theoretical world where you can engine-brake down some eternal hill, MAYBE the car would use less fuel under engine-braking than idling in neutral, since the wheels would turn the engine.
In the more realistic world, we can get better mileage by coasting down many hills and letting the inertia of the speeding car carry us up the next incline better, faster, farther.
On that theoretical eternal downhill slope, you could turn the engine completely off, or better yet, ride a bicycle. No need to use any gas at all.
In the more realistic world, we can get better mileage by coasting down many hills and letting the inertia of the speeding car carry us up the next incline better, faster, farther.
On that theoretical eternal downhill slope, you could turn the engine completely off, or better yet, ride a bicycle. No need to use any gas at all.
Last edited by Steeldog; 08-12-2008 at 10:01 AM.
#62
08-06-2008, 11:47 PM
I'm with the "coast in high gear" crowd, to maximize fuel efficiency.
That said, I've started downshifting out of 5th since I notice the car will start lugging (choking) a bit below 35 km/h as the RPMs drop below the 5th gear's minimum operating level.
I leave it in neutral when stopped, even turn the car off if I know it'll be red for at least half a minute... IIRC starting modern cars consumes the equivalent of 9 seconds of gas while idle.
That said, I've started downshifting out of 5th since I notice the car will start lugging (choking) a bit below 35 km/h as the RPMs drop below the 5th gear's minimum operating level.
I leave it in neutral when stopped, even turn the car off if I know it'll be red for at least half a minute... IIRC starting modern cars consumes the equivalent of 9 seconds of gas while idle.
#63
08-10-2008, 02:22 PM
Shifting in to gear adds response time to performing emergency maneuvers. Not always braking! So coasting in neutral is generally a bad idea, but I'm a gambling man. Do what you want. It is more dangerous, but only slightly.
#64
12-20-2008, 05:36 PM
Well I just got some information (learned a new thing or two..) about the disc brakes vs drum brakes and brake fading;
When braking for a long time with drum brakes, the drum got hot and when metal get hot it expands, when the drum expand the brake fades and you have to press the pedal in further to get the same amount of braking.
When braking for a long time with disc brakes, the metal disc expands and therefor gives more braking power and actually slow down the car faster.
And because of this fact more and more cars is equiped with disc brakes today. But disc brakes is a bit more expensive...
But this topic was about coasting in neutral...
I still dont think on it as unsafe to coast in neutral, but it is more logic to use the engine to brake (coasting in gear) for you to save the brakes, and get lower fuel usage at the same time.
When braking for a long time with drum brakes, the drum got hot and when metal get hot it expands, when the drum expand the brake fades and you have to press the pedal in further to get the same amount of braking.
When braking for a long time with disc brakes, the metal disc expands and therefor gives more braking power and actually slow down the car faster.
And because of this fact more and more cars is equiped with disc brakes today. But disc brakes is a bit more expensive...
But this topic was about coasting in neutral...
I still dont think on it as unsafe to coast in neutral, but it is more logic to use the engine to brake (coasting in gear) for you to save the brakes, and get lower fuel usage at the same time.
I don't know where you got this information from but it absolute BS. A few reasons for disk over drum are ,
Disks cool-off better than drums,,,,
Disk DO give better braking mostly because you are applying friction to the turning rotor at a place further from the center of the axle. This larger diameter gives the brake pad/caliper more leverage to stop the turning rotor. Kinda like the difference of prying with a 2 foot bar is harder than prying with a 10 foot bar) The drum system is generally a smaller diameter on the same vehicle.
The other good reason for disk brakes is they are much easier to work on in most cases. Not alot of little springs and other crap to work with.
Now about why brakes fade. The story about the larger gap on hot drum brakes making them fade has got to be minimal. And there is NO WAY that the hotter the disk brake gets the better they work, pure BS!!!! ( although disk brakes TOLERATE heat better, and will work better for longer at a higher temp than drums,)The reason either brake system fades is the building of heat in the two componnets that touch eash other,,,,the drum or disk and the brake pad,,,pure and simple,,,heat them up and they lose the ability to resist the movement of the rotateing wheel,,,(less friction) they just start grinding each other away with little stopping power to the wheels.
Now all that said there are MANY more factors that effect braking. There are metal based brake pads that DO get better at stopping after reaching a higher temp,,,,but they fade like all the rest when they get to hot.
I'd like to know the source of your new found knowledge, because I think it's bogus,,,but that's just MHO
PS don't take this as a personal attack...I'm sure you mean well ,,,we just don't agree with each other and that's allowed here I think,,,
peace
#65
12-21-2008, 02:48 PM
OK this statement has got me posting here after I told myslef that I would'nt,,,,,( I know it's been an ongoing battle but it all in good fun right? exchange of information is a good thing)
I don't know where you got this information from but it absolute BS. A few reasons for disk over drum are ,
Disks cool-off better than drums,,,,
Disk DO give better braking mostly because you are applying friction to the turning rotor at a place further from the center of the axle. This larger diameter gives the brake pad/caliper more leverage to stop the turning rotor. Kinda like the difference of prying with a 2 foot bar is harder than prying with a 10 foot bar) The drum system is generally a smaller diameter on the same vehicle.
The other good reason for disk brakes is they are much easier to work on in most cases. Not alot of little springs and other crap to work with.
Now about why brakes fade. The story about the larger gap on hot drum brakes making them fade has got to be minimal. And there is NO WAY that the hotter the disk brake gets the better they work, pure BS!!!! ( although disk brakes TOLERATE heat better, and will work better for longer at a higher temp than drums,)The reason either brake system fades is the building of heat in the two componnets that touch eash other,,,,the drum or disk and the brake pad,,,pure and simple,,,heat them up and they lose the ability to resist the movement of the rotateing wheel,,,(less friction) they just start grinding each other away with little stopping power to the wheels.
Now all that said there are MANY more factors that effect braking. There are metal based brake pads that DO get better at stopping after reaching a higher temp,,,,but they fade like all the rest when they get to hot.
I'd like to know the source of your new found knowledge, because I think it's bogus,,,but that's just MHO
PS don't take this as a personal attack...I'm sure you mean well ,,,we just don't agree with each other and that's allowed here I think,,, peace
I don't know where you got this information from but it absolute BS. A few reasons for disk over drum are ,
Disks cool-off better than drums,,,,
Disk DO give better braking mostly because you are applying friction to the turning rotor at a place further from the center of the axle. This larger diameter gives the brake pad/caliper more leverage to stop the turning rotor. Kinda like the difference of prying with a 2 foot bar is harder than prying with a 10 foot bar) The drum system is generally a smaller diameter on the same vehicle.
The other good reason for disk brakes is they are much easier to work on in most cases. Not alot of little springs and other crap to work with.
Now about why brakes fade. The story about the larger gap on hot drum brakes making them fade has got to be minimal. And there is NO WAY that the hotter the disk brake gets the better they work, pure BS!!!! ( although disk brakes TOLERATE heat better, and will work better for longer at a higher temp than drums,)The reason either brake system fades is the building of heat in the two componnets that touch eash other,,,,the drum or disk and the brake pad,,,pure and simple,,,heat them up and they lose the ability to resist the movement of the rotateing wheel,,,(less friction) they just start grinding each other away with little stopping power to the wheels.
Now all that said there are MANY more factors that effect braking. There are metal based brake pads that DO get better at stopping after reaching a higher temp,,,,but they fade like all the rest when they get to hot.
I'd like to know the source of your new found knowledge, because I think it's bogus,,,but that's just MHO
PS don't take this as a personal attack...I'm sure you mean well ,,,we just don't agree with each other and that's allowed here I think,,,
peaceDefinitely bull shit about significant metal expansion! Good correction.
Last edited by MPGASAP; 12-21-2008 at 02:51 PM.
#66
12-21-2008, 05:55 PM
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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.
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.
obviously its risky so no comments just stating that is dangerous plz
#67
12-21-2008, 05:59 PM
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with the engine off u get infinity mpg!!!
#68
12-21-2008, 06:06 PM
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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 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.
#69
12-21-2008, 06:07 PM
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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.
#70
12-21-2008, 06:14 PM
Ugh, I had hoped this thread had died.
Having the car in gear while holding the clutch in for longer than needed puts unnecessary wear on the clutch.
Having the car in gear while holding the clutch in for longer than needed puts unnecessary wear on the clutch.
#71
12-25-2008, 03:58 AM
it is save if u know how to drive, and have quick thinking and respond! i usually do it. Coasting in neutral about 200 feet from red light or turn, downhill, and leave the gear on neutral on red light (for this one, u gotta be quick to put the gear in when the light turn green).
ps: been through 8 cars and all were m/t, and now driving GD3 m/t sport.
ps: been through 8 cars and all were m/t, and now driving GD3 m/t sport.
#72
12-26-2008, 07:57 PM
My 1971 Saab 99 had a "freewheel" transmission that gave the driver the option of pulling a lever to allow the car to freewheel if the car was going "faster" than the engine. If you were idling, such as going down a hill, the car would coast. You could step on the gas to bring the engine revs back up and the drive train would smoothly re-engage and you would just drive normally. You didn't have to use the clutch at all. If you pulled back on the lever next to the gearshift (manual transmission), then the transmission and clutch worked conventionally.
Here is a link to a Wikipedia article on the car: Saab 99 - Wikipedia, the free encyclopedia
I got used to using the freewheeling. It never worked after a shop rebuilt the transmission following a failure (like everything else on the Saab). I didn't notice anything particularly unsafe about it. The car was quirky, but had front-wheel drive, unusual in its day. It broke down all the time, but my long-suffering wife allowed that the car had the most comfortable seats to sit in while we waited for the tow truck.
Here is a link to a Wikipedia article on the car: Saab 99 - Wikipedia, the free encyclopedia
I got used to using the freewheeling. It never worked after a shop rebuilt the transmission following a failure (like everything else on the Saab). I didn't notice anything particularly unsafe about it. The car was quirky, but had front-wheel drive, unusual in its day. It broke down all the time, but my long-suffering wife allowed that the car had the most comfortable seats to sit in while we waited for the tow truck.
#73
12-26-2008, 08:34 PM
Way too much going on here for such a simple concept.
When at a red light, I'm in NEUTRAL.
When slowing down, I'm in GEAR until 15-20mph then NEUTRAL because the car starts to hiccup if you leave it in gear with clutch OUT.
That's all anybody should be doing. You could add in some heel-toe if you want, that's fine. I don't downshift to a stop, just to pass, and I don't match revs. It's hard to do that for me in the Fit.
When at a red light, I'm in NEUTRAL.
When slowing down, I'm in GEAR until 15-20mph then NEUTRAL because the car starts to hiccup if you leave it in gear with clutch OUT.
That's all anybody should be doing. You could add in some heel-toe if you want, that's fine. I don't downshift to a stop, just to pass, and I don't match revs. It's hard to do that for me in the Fit.
#74
12-26-2008, 10:24 PM
My 1971 Saab 99 had a "freewheel" transmission that gave the driver the option of pulling a lever to allow the car to freewheel if the car was going "faster" than the engine. If you were idling, such as going down a hill, the car would coast. You could step on the gas to bring the engine revs back up and the drive train would smoothly re-engage and you would just drive normally. You didn't have to use the clutch at all. If you pulled back on the lever next to the gearshift (manual transmission), then the transmission and clutch worked conventionally.
Here is a link to a Wikipedia article on the car: Saab 99 - Wikipedia, the free encyclopedia
I got used to using the freewheeling. It never worked after a shop rebuilt the transmission following a failure (like everything else on the Saab). I didn't notice anything particularly unsafe about it. The car was quirky, but had front-wheel drive, unusual in its day. It broke down all the time, but my long-suffering wife allowed that the car had the most comfortable seats to sit in while we waited for the tow truck.
Here is a link to a Wikipedia article on the car: Saab 99 - Wikipedia, the free encyclopedia
I got used to using the freewheeling. It never worked after a shop rebuilt the transmission following a failure (like everything else on the Saab). I didn't notice anything particularly unsafe about it. The car was quirky, but had front-wheel drive, unusual in its day. It broke down all the time, but my long-suffering wife allowed that the car had the most comfortable seats to sit in while we waited for the tow truck.
"A freewheel also produces slightly better fuel efficiency and less wear on the manual clutch, but leads to more wear on the brakes as there is no longer any ability to perform engine braking." This is why I say on bigger hills if you are using alot of brake pressure to slow you down it's prolly not a good time to be coasting,,,,,,
Great artical and an interesting car,,,thanks for the post!!
#75
12-27-2008, 03:26 AM
In my old 1979 Fiesta, I used to coast down long downhills (southbound 101 near San Luis Obispo, CA, traffic permitting) with the engine off! This was possible because the car did not need engine vacume because it did not have power brakes. I could easily start it my letting the clutch out in top (4th) gear and it wasn't for a prolonged period like being towed behind an RV. With my 2008 Fit Sport MT, I coast (traffic permitting) on slight downhills whenever possible with the engine idleing as long as I don't have to use the brakes to control my speed. I think the danger would be if the engine died then you'd loose the vacume which I think powers the brake assist. According to the Scan Gauge, the engine shuts off fuel to the engine when the engine is used for braking. On a steeper downhill, in this case. no fuel is consumed and you save your brakes a bit.
On another note, I was wondering why Honda used rear drum brakes. Cheaper? Or is it that the pads do not contact the drum unless the brakes are applied. With disc brakes, on the other hand, the pads are always in contact with the disc. Any thoughts?
On another note, I was wondering why Honda used rear drum brakes. Cheaper? Or is it that the pads do not contact the drum unless the brakes are applied. With disc brakes, on the other hand, the pads are always in contact with the disc. Any thoughts?
#77
12-27-2008, 10:10 AM
I hate having my foot on the clutch. I do not sit at a light with the clutch in. My foot gets all weird and tired. I hate being in cars with people that love to ride the clutch. I don't say anything because I don't want to start shit but damn...clutch is only for shifting. Not braking.
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