OK to coast downhill in Neutral?

[hampyoung]

I'm still hoping to get the technical explanation of why it could be bad ** for the engine, transmission or whatever. The only thing I know of is the lack of lubrication to the transmission ** but for 1 or 2 miles; is it enough to worry about?
The reasons for why someone likes/dislikes the idea or thinks its right/wrong or worthwhile or not ** those are all another topic.

[cains10]

Had a feature called freewheeling which automatically let the engine go to idle when coasting. You had to bring the revs up to the applicable speed to re-engage the transmission and continue on your merry way. So the car was manufactured to coast with the engine at idle and they had a very safe reputation. Freewheeling could be disconnected (or connected) (double negative???), anyway I know what I mean. And it had a three cylinder engine!

[Dunerunner]

Originally Posted by hampyoung

I'm still hoping to get the technical explanation of why it could be bad ** The only thing I know of is the lack of lubrication to the transmission ** but for 1 or 2 miles; is it enough to worry about.

This car can be towed on all fours with the transmission in Neutral and the engine off, I doubt there would be any lubrication issues with the transmission while coasting. The only issues are the legal problem, the transmission re-engaging at highway speeds and your ability to control the vehicle.

[dennyrex]

DKWs also had free-wheeling.

[shack01]

Originally Posted by whalepirot

No, the drivetrain is turning the engine, so NO fuel is needed to keep it going. Below a certain RPM, probably around 1500, a small amount if fuel is squirted.

As was stated a few times: in neutral, the drivetrain cannot rotate the engine, so idle fuel is consumed, and higher fuel consumption is indicated on the 'Scan'.

Been thinking about this for the last week or so and perhaps you are correct, that the "system" knows that the engine is being turned by the transmission and therefore provides no fuel. That might explain the scangauge mysteries.

tm

[rawlus®]

Originally Posted by Dunerunner

This car can be towed on all fours with the transmission in Neutral and the engine off, I doubt there would be any lubrication issues with the transmission while coasting. The only issues are the legal problem, the transmission re-engaging at highway speeds and your ability to control the vehicle.

from page 278 of the owner's manual.

When towing the vehicle with all wheels on the
ground or the front axle raised, the vehicle
may be towed only for distances up to 30 miles
(50 km) and at a speed not to exceed 30 mph
(50 km/h).

[Karl Roth]

I had a peddle car with a direct drive on the front wheels and we lived on a steep hill. About a quarter of the way down my feet could not keep up anymore and it really started moving. it also started to sway back and forth and the best way to describe the ride was totally out of control. At the halfway mark I hit a storm sewer drain and the front wheels stopped the back keept going as did I. Remember seeing the marker #'s on the phone pole as I flew past. Made a four point landing that turned into five when the chin went in. Still have the scars but haven't had any trouble with coasting since that time.
Brakes have come a long way along with tires since the MG TC. You could stop one hard once and then you needed to let it cool for an hour or so. Still live in the hills and you can see the cars with automatics by looking for the brake lights coming on going down the hills.
have fun karl

[Dunerunner]

Originally Posted by rawlus®

from page 278 of the owner's manual.

Look in the towing sub-forum - Flat Tow ?? YES!!!

I towed my smart 178 miles from the hitch insaller to my home at freeway speeds with no issues and intend to flat tow it behind my motorhome as has been done with the 450's for years.

[bull8042]

Towing a vehicle with the driven wheels on the ground can cause damage to the transmission, IF it has a true automatic tranny. The automatic must be internally rotating, driven by the engine to effectively pump the lubricating/cooling fluids through the moving parts.
A manual transmission however, relies on it's gears being immersed in the oil to "sling" the lube into the moving parts for lubrication.
The manual does in fact state "not above 30 mph", but I am more inclined to believe that is more of a safety concern and an attempt to limit liability rather than a concern about damage to the smart.
I can not think of a way that the vehicle would be damaged by coasting in neutral, engine running or not. My ONLY concern is the effect of re-engaging the gearing without the luxury of a clutch once you reach the bottom.
I am currently designing a machine for Getrag, so if I have the opportunity to "hob-nob" with any of their engineers, I will most definitely pose the question myself.

[hampyoung]

Smart says they're rewriting the towing section of the manual to reflect the actual allowed practice of towing 4 on the ground.