Steady driving vs Cruise control

[Mic]

None of my 3 cars will allow CC to work, below 30mph. There again, there's nowhere here where 20mph cruising is possible, nor desired

I am not sure any do......do they?......why would you want to choose have settled for a constant speed below three figures?

Mic

 

[The Pan Man]

When you are riding motorcycles it's called throttle control. In a car it's all about controling the accelerator pedal. The key word in both statements is "Control". When you use CC it will maintain a speed but it will always be pushing fuel into the system, when you do this manually you have the choices to make, when and how much. Has anyone else noticed the difference between diesel and petrol when it comes to rolling inertia, is it just because the engine is heavier and mounted at the front.

 

[sailorjim]

On flat motorways - cruise control; on hilly motorways you will use more fuel because, as noted above, the dumb machine cannot read the road ahead. For example, it's better to lose a bit of speed on the uphill stretches and get it back on the downhill bits, like the tube trains do.

Where I have found a considerable improvement with cruise control is at speeds between 30 and 50 mph on our appalling roads. The only reason i can think of for this is that every time you go over a pot hole, bump etc you can't avoid your right foot bouncing a bit on the accelerator, so maybe the system perceives this as the start of a "kick-down" and alters the fuel mixture accordingly? I know that I get about 10% difference (according to the computer, of course) between using and not using on poor roads.

 

[The Pan Man]

Sailorjim, Good point you are also in the next county to me so I know all about the roads. Had a claim off Birmingham City Council about 4 years ago, talk about dealing with numpty and his mates. Did get paid in the end.

 

[hawk20]

Hey people I'm pretty sure that my steady driving on the motorway can achieve better mpg results than cruise control (at the same speed).. Or is that not even possible ?

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Depends what you mean by at the same speed.
Same constant speed? Then cruise is best.
Same average speed? Then you might beat cruise by being that most annoying of drivers who speeds up on every small downhill stretch and slows up on every slight incline.

Cruise will hold a constant cruising speed on long open stretches far more accurately and with less variation than almost all humans. Nobody has perfect concentration. Nobody wants to keep checking the speedo every few seconds. But cruise can do that for you.

It is not possible on our busy roads to do a truly scientific test -tankful to tankful- at a constant speed for very long distances. Traffic always messes up your test. So every time we have this subject raised we get those who say cruise uses less fuel and those who say their amazing skill means they use less. But you can never make the conditions good enough to really know.

Truth is that cruise is wonderfully convenient. It may or may not be a bit better than a human on economy. But it sure is more accurate at holding a constant cruising speed.

I use mine in speed restricted areas every day. Excellent.

Driving 1,000 miles from my home to the South of France on several occasions I have tried some days with cruise and some without on long motorway stretches with little traffic. No real difference that I could detect.

 

[JEZ.S320L]

To echo hawk20, for long distances then CC is easier on the constant speed-checking. I have travelled to and from from Calais, Santander and Bilbao a number of times and every time, have been able to use CC for 95% of the time (thank God for Toll Roads).
At least I can shuffle my feet around and avoid cramp, at the same time just having to steer, view and monitor. Brilliant.
As for fuel consumption, I did manage an almost-unheard-of 17mpg in the Navigator over 500 miles, which is pretty damn good IMHO.

 

[television]

Well you still cannot go by what Hawk says for we do not know how he drives, or anyone else for that matter.

Standard CC cannot anticipate the road ahead, but you can, the same for inclines and every thing else.

CC will force a gear change, that is not good on an economy run, you can drive the car so as to not force a change down.

Sure there probably is not much in it, but CC and distronic is so nice to have to relax with, like turning the aircon off at 30c to save on fuel.

 

[whitenemesis]

I concur with hawk20 and jez, very difficult to be 100% scientific on the affect on mpg because of varying traffic conditions but the convenience factor is indisputable. To keep checking one's speed is tiring and distracting. Distronic is even more convenient to use but fuel saving? Not what I would use it for..

 

[television]

I concur with hawk20 and jez, very difficult to be 100% scientific on the affect on mpg because of varying traffic conditions but the convenience factor is indisputable. To keep checking one's speed is tiring and distracting. Distronic is even more convenient to use but fuel saving? Not what I would use it for..

The question was "Steady driving vs Cruise control" and the answer is steady driving through all the reason stated,,, you have a brain, CC does not

 

[teabag]

Same average speed? Then you might beat cruise by being that most annoying of drivers who speeds up on every small downhill stretch and slows up on every slight incline.

I endorse that comment 100% as this behaviour drives everyone else nuts.

 

[television]

I endorse that comment 100% as this behaviour drives everyone else nuts.

You mean like a 40 ton truck, now I wonder why, and some litle cars have no choice

 

[whitenemesis]

The question was "Steady driving vs Cruise control" and the answer is steady driving through all the reason stated,,, you have a brain, CC does not

This always annoys me.. Cruise Control will provide the ultimate "steady driving" i.e. steady speed. CC does have a "brain" in as far as any automated device has a brain. Humans will drift, will slow uphill and allow the car speed up down hill. Concentration on speed will not be 100% and so it shouldn't. There are many other driving related concerns that demand attention. CC is never distracted from the task of maintaining a constant speed.

Whether it makes any difference to mpg is not clear cut, simply because any "test" on the public road will have too many variables to be 100% reproducible.

 

[teabag]

You mean like a 40 ton truck, now I wonder why, and some litle cars have no choice

No Malcolm, I'm talking about the person who slows down from 70 on the flat to 60 on a slight uphill incline and allows you to overtake him just to come past you at 80 on a downhill stretch and start the whole sequence again at the next gradient.

 

[television]

No Malcolm, I'm talking about the person who slows down from 70 on the flat to 60 on a slight uphill incline and allows you to overtake him just to come past you at 80 on a downhill stretch and start the whole sequence again at the next gradient.

This still has nothing to do with CC bring more economical than the user.

Plus this has been going on since the motorways were first started.

As I said many cars slow down on inclines if they are loaded and have a small engine and require a lot of throttle, if the owner does not want to go up in a lower gear so they just keep going the best they can and make up for it on the down going side.Its OK for us in powerful Mercs to be able to hold a more steady speed, with or without CC.

You may have noticed what it says in some handbooks, "a car will use more petrol going up hill than going downhill, I wonder why

 

[Naraic]

You may have noticed what it says in some handbooks, "a car will use more petrol going up hill than going downhill, I wonder why

...because there are some very stupid people out there...they need to be told.

 

[television]

...because there are some very stupid people out there...they need to be told.

But really the things that are being talked about are not what was asked, believe me I have driven a 1.4 fiesta along 400km of motorway and there was no way that the car would go faster than 90kph up some of the long inclines, so I just made up for it going down the other side, this will always go on and it has nothing to do with your CC.

 

[Naraic]

But really the things that are being talked about are not what was asked, believe me I have driven a 1.4 fiesta along 400km of motorway and there was no way that the car would go faster than 90kph up some of the long inclines, so I just made up for it going down the other side, this will always go on and it has nothing to do with your CC.

That must have been some time ago...and even then, my Renault12ts in the 70s had no problem sustaining high speeds (and 90kph is only 52.5mph, so not even a high speed), and it was a 1300. I also had 1300 Alfas and Vauxhalls...no problem there either.

 

[television]

That must have been some time ago...and even then, my Renault12ts in the 70s had no problem sustaining high speeds (and 90kph is only 52.5mph, so not even a high speed), and it was a 1300. I also had 1300 Alfas and Vauxhalls...no problem there either.

Nope just a few years back and a 1995 car for the record 90kph is as near as dam it 56mph

 

[whitenemesis]

Pretty sure any Mercedes (and this is a Mercedes forum after all) with cruise control would have no problem maintaining a constant speed up hill...

 

[st4]

Pretty sure any Mercedes (and this is a Mercedes forum after all) with cruise control would have no problem maintaining a constant speed up hill...

Driving fast up hills is their speciality. I mean most cars on here are over 2litre and a good chunk over 3litre so they go well.

Slowing down on hills is for slow lorries and buses.

Charging up a steep hill and watching the needle swing past 120mph (in germany) is one of these all time automotive delights....LOL