[ganeshram]

I have of late seen many Manual transmission cars offering cruise control. A simple question - If the vehicle electronics cannot change gears because it is a manual transmission, what sense does the cruise control make? If you have to change the gears to maintain the speed, then absolutely no point in having a cruise control in the first place.

I asked one of the sales executives accompanying me in a test drive - whether CC actually makes sense in a MT car and he just smiled.

Point I am trying to make - Does CC in a MT car mean just accelerator hold? I have driven cars in the US, where the resume button would make sure that the gear shifts are made in the right possible manner to achieve the last set speed.

Comments welcome!

[Mpower]

My goodness yes! I've had CC on my manual cars since 10+ years (2 different cars)

Yes you have to intervene more often because it cannot change gears (like when you hit an upslope) but like it says its just a 'cruise control' to relax your foot.... not robotic drive.

[mjumrani]

I think it is good even in a manual car.
I use it almost every day for atleast 40kms of the 90kms I drive daily.

Civic's CC slows acceleration and deceleration from the panel itself, so many a times they suffice.

Especially a boon when the foot starts hurting.

[SS-Traveller]

Originally Posted by ganeshram

Does CC in a MT car mean just accelerator hold?

What else can it function as? My right foot is happy that CC exists to just do that, when I drive extra-long distances.

[dhanushs]

Cruise control is mainly a comfort feature, and does not substitute a driver on extreme situations like steep inclines, negotiating traffic where you slow down and the cruise control accelerates the car back to the set speed.

Most of new gen cars gears have good power/torque mated with good gearing to give a nice range (~50-~150kmph in 5th?), for cruise control to act and hence help us ease our right foot.

I think that is all what Cruise Control is aimed at, and not really substituting the driver to propel the car.

[lamborghini]

Cruise control just maintains the speed of the car at a constant. This allows the driver to relax a little bit on long drives, as opposed to keeping his foot on the accelerator at a particular level to maintain his speed on long drives.
Unless it is adaptive cruise control, which slows down if the car ahead slows down as well, I have never experienced the gears needing to be changed with it (regular cruise control) activated, as the speed doesn't change - and given this, it should hold on a MT car as well.
From my experience, climbing a slight slope, or moving down a gentle slope, the cruise control maintains the speed and the gear (with a little variation on the speed), without changing the gear (unless the rpm falls too low - which is something that shouldn't happen if the slopes are gentle, and if it is slightly hilly terrain, avoid cruise control completely IMO - this is where a MT is most fun to drive, so why use cruise control, right? ).

[VCheng]

Cruise control is intended for steady conditions only. Most cars have ample reserves of torque at cruising speeds to maintain speed with wider throttle. Automatics have an advantage that they may change gears by themselves if the throttle opening is insufficient, but that also implies that the grade is quite steep. In addition to brake cancel switches in both types, manual also has a clutch cancel switch.

Most auto manufacturers will have a built-in safety feature that will cancel cruise even in an automatic if more than a set percent change in fuel flow, depending on vehicle type and gearing, is needed to maintain set speed.

Similarly, if a downgrade is so steep that a downshift is not able to hold the increase in speed despite providing increased engine braking, cruise control is cancelled.

Bottom line is that cruise is a convenience feature for both manual and automatics and should be used as such, with constant attention to road conditions.

[Sanjunair5]

Well actually it does. I drive a MT Ford Fusion with CC on it. And I too was curious the way you are about how it functions. So one day I experimented a bit and found this;
1. CC does not come 'on' on any gears below 3
2. CC does not come 'on' below 30 MPH
3. It does not warn you in any way if you set CC at (say) 80MPH in 3rd gear. CC will happily run the engine at 5000 RPM for maintaining 80MPH in 3rd gear. So you need to be a good, informed and alert driver and shift to a higher gear, unlike in the case ATs where the AT does the gear selection.

But once you are in 5th and have a clear road in front of you just switch to CC and relax. And it is very convenient.

[libranof1987]

Given that cruise control would try to maintain speed *on the same gear* on a MT, engaging cruise control would hence result in a lower FE than on an AT, right?

[Sanjunair5]

Originally Posted by libranof1987

Given that cruise control would try to maintain speed *on the same gear* on a MT, engaging cruise control would hence result in a lower FE than on an AT, right?

That is right, to extract maximum efficiency one should engage CC when truly 'cruising' on top gear, not in lower gears and, not when one expects to change gears. I use the step up/down control to change CC set speed when I need to vary speed without changing gears.

[mayankjha1806]

It does make sense for me, as on highway when one is doing a long and almost constant speed CC helps in giving the right foot some much needed rest so when the traffic areas come it can work better. Offcourse if the situation on the roads demands slowing down to crawling speeds (like a speed breaker) then it might be more painful to engage CC.

In the CC of my Civic i can alter speeds (up/down) depending on the situation on the highway or the speed limits enforced on the highway. Have used it decently on our drive to Raipur and reduces the pain, especially in the day time (At night time i have not used it as it has a tendency to induce sleep).

[DudeWithaFiat]

Originally Posted by Sanjunair5

Well actually it does. I drive a MT Ford Fusion with CC on it. And I too was curious the way you are about how it functions. So one day I experimented a bit and found this;
1. CC does not come 'on' on any gears below 3
2. CC does not come 'on' below 30 MPH
3. It does not warn you in any way if you set CC at (say) 80MPH in 3rd gear. CC will happily run the engine at 5000 RPM for maintaining 80MPH in 3rd gear. So you need to be a good, informed and alert driver and shift to a higher gear, unlike in the case ATs where the AT does the gear selection.

Is that a common CC feature? Its like that in all the other cars equipped with CC or its just a Ford feature? I believe it should be that way with all the other CC'd cars.

[androdev]

What no one mentioned is the use of CC to stick to "speed limits". It is super convenient to drive with CC on roads that have strict speed limit enforcement, you just do +/- as you move across different speed limit zones and don't have to keep looking at the speedo to adjust the A-pedal. I make lot of trips to airport in Bangalore where they strictly enforce 80kmph speed limit and I used CC with MT all the time. Of course, the road is all dug up now for construction and they don't have to enforce any speed limits

If there are no speed limits and you have the freedom to choose your speed, I don't find much use with CC.

[StarrySky]

I'm usually a sedate driver and keep to 70-80kmph during my trips on the highway (Cochin-Thrissur). I feel safe at this speed and it also returns great FE. The downside is that keeping a constant speed for long time on the 4-lane sections is a pain in the right leg, literally. That usually makes me wish I had CC in my car.

[iliketurtles]

The short answer to your question would be a yes. As many have pointed out, it makes sense to engage cruise control only when you are going at a steady speed on an open stretch. If you're doing a lot of city driving only, then cruise control would make no sense whatsoever given the serpentine traffic we face in all our metros. On the highway, however, Cruise Control is a definite boon.

So yes, it does help to have Cruise Control in a manual transmission car, but not if you're just a city slicker whose drive involves tons of traffic and very little else.