How to drive downhill?

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Deleted User 3871

Post by Deleted User 3871 »

It's not just a gearbox or brakes. It's about using them together to reduce the strain on either component. It's also about driving style. Your most probably a good technical driver and looking after all the components of your car, van or truck. There are a lot of people out there who don't understand a vehicle in the same detail as yourself & are probably best suited to an Auto Gearbox and use the brakes to slow down and throttle for go.
gloucester wrote: Fri Nov 26, 2021 1:45 pm I've been driving for 46 years and I've not had a gearbox or clutch fail owing to being overworked. Hence I'll continue to use the gearbox...

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Foffer
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Post by Foffer »

Using the transmission was necessary to assist the brakes on cars in the past to avoid them overheating and fading. Modern cars braking systems are not only capable of stopping or slowing the car under all circumstances but are by far the safer option. All those clever ABS and other intelligent safety systems built into the brakes are bypassed when using the transmission. This is why the Institute of Advanced Motorists advise "Gears are for going, brakes are for slowing".
Current car: 2021 Qashqai Tekna+ DIG-T MHEV CVT
Previous car: 2019 Qashqai Tekna+ 1.3 DIG-T 160 DCT
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gloucester
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Post by gloucester »

Foffer wrote: Thu Dec 02, 2021 8:30 pm
.... the Institute of Advanced Motorists advise "Gears are for going, brakes are for slowing".

I think you're confusing their advice for, say, approaching a junction or traffic lights, with their advice for going downhill which reads to me more like using the gears:

From various sources:

gear.JPG



It is not always possible to apply accelerator sense downhill because gravity often wins the tussle but being in the correct gear will assist greatly and the general rule here is; ‘descend a hill in the gear you would usually select to ascend it’. However, if you do need to brush off more speed as you approach a lower speed limit (for instance, you may have selected 3rd gear but know you will need 2nd gear for a new 30mph limit) consider braking down to around 27-28mph before getting the 2nd gear because by the time you have engaged the new gear gravity will have brought you back up to 30mph.

Driving down hill
Remember a low gear should be selected at an early stage in the descent. When it is necessary to slow down on steep winding descents, brake firmly on the straight stretches and gently on the bends.



Also note:

Believing you will save fuel by coasting in neutral or with the clutch disengaged in any situation is a complete myth in a modern car - and it comes with potential dangers! Keeping the engine of a modern car running and in gear when descending a hill (assuming your foot is off the accelerator pedal) will automatically shut the fuel supply to zero which means that absolutely no fuel will be delivered to the engine - whereas coasting with the car in neutral will actually use fuel in order to keep the engine ticking over. So, drivers of a certain era - be careful; if you teach or adopt the practice of selecting neutral when travelling downhill (or indeed whenever the vehicle is moving) and your engine cuts out, you will immediately lose power steering control and your servo assisted brakes. Just as an added word of warning; you would fail the IAM RoadSmart and RoSPA Advanced Driving Test if you select neutral to travel downhill.
(2015 Nissan Qashqai Tekna DIG-T 1.2 sold 15/6/18) ~ 2018 Suzuki Ignis SZ5 - 2018 Yamaha MT-07 ~ (2024 Volvo EX30 ordered)
Deleted User 3871

Post by Deleted User 3871 »

This is incorrect, it just depends on the car.

Until recently I had a BMW M140i with an auto gearbox. As part of the eco mode, the car would coast, It was a bit like freewheeling, but I don't know the exact details on how this works. It is kind of contrary to what I thought was best practice in general driving as well as fuel saving., but there it is.
https://www.ecosia.org/search?q=bmw%20e ... opensearch

"you will immediately lose power steering control and your servo assisted brakes"
This is total Bullcrap .. servo-brakes will give you several pumps before depleting as there is a NRV to stop the loss of vacuum pressure. Some cars use hydraulic pressure from the ride height system to assist brakes, Citroen CX and probably others.

Power steering usually goes instantly in my experience, but some cars are designed to stop the engine, so again, it all depends on the Car
gloucester wrote: Fri Dec 03, 2021 12:38 pm Believing you will save fuel by coasting in neutral or with the clutch disengaged in any situation is a complete myth in a modern car - and it comes with potential dangers! Keeping the engine of a modern car running and in gear when descending a hill (assuming your foot is off the accelerator pedal) will automatically shut the fuel supply to zero which means that absolutely no fuel will be delivered to the engine - whereas coasting with the car in neutral will actually use fuel in order to keep the engine ticking over. So, drivers of a certain era - be careful; if you teach or adopt the practice of selecting neutral when travelling downhill (or indeed whenever the vehicle is moving) and your engine cuts out, you will immediately lose power steering control and your servo assisted brakes. Just as an added word of warning; you would fail the IAM RoadSmart and RoSPA Advanced Driving Test if you select neutral to travel downhill.
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Foffer
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Post by Foffer »

gloucester wrote: Fri Dec 03, 2021 12:38 pm
Foffer wrote: Thu Dec 02, 2021 8:30 pm
.... the Institute of Advanced Motorists advise "Gears are for going, brakes are for slowing".

I think you're confusing their advice for, say, approaching a junction or traffic lights, with their advice for going downhill which reads to me more like using the gears:

From various sources:


gear.JPG


It is not always possible to apply accelerator sense downhill because gravity often wins the tussle but being in the correct gear will assist greatly and the general rule here is; ‘descend a hill in the gear you would usually select to ascend it’. However, if you do need to brush off more speed as you approach a lower speed limit (for instance, you may have selected 3rd gear but know you will need 2nd gear for a new 30mph limit) consider braking down to around 27-28mph before getting the 2nd gear because by the time you have engaged the new gear gravity will have brought you back up to 30mph.

Driving down hill
Remember a low gear should be selected at an early stage in the descent. When it is necessary to slow down on steep winding descents, brake firmly on the straight stretches and gently on the bends.



Also note:

Believing you will save fuel by coasting in neutral or with the clutch disengaged in any situation is a complete myth in a modern car - and it comes with potential dangers! Keeping the engine of a modern car running and in gear when descending a hill (assuming your foot is off the accelerator pedal) will automatically shut the fuel supply to zero which means that absolutely no fuel will be delivered to the engine - whereas coasting with the car in neutral will actually use fuel in order to keep the engine ticking over. So, drivers of a certain era - be careful; if you teach or adopt the practice of selecting neutral when travelling downhill (or indeed whenever the vehicle is moving) and your engine cuts out, you will immediately lose power steering control and your servo assisted brakes. Just as an added word of warning; you would fail the IAM RoadSmart and RoSPA Advanced Driving Test if you select neutral to travel downhill.
I have spent some time looking at what is advised by all sorts of different organisations and conclude that the advice seems to be mixed! Using a low gear for going downhill appears to be the right answer in today's theory test, so I must acknowledge that you might be right!!
Current car: 2021 Qashqai Tekna+ DIG-T MHEV CVT
Previous car: 2019 Qashqai Tekna+ 1.3 DIG-T 160 DCT
Qashowner
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Post by Qashowner »

From reading most of the above, I think it depends on how old we are. I am 70 and was taught totally differently on the use of gears than my children. For example, approaching a junction we were taught to change down through the gears so we were in the rights gear to pull away if the road was clear, my children mutter on about block changing, but they are happy to drive my auto :D

Driving down hill we were taught to use a low gear and not rely on the brakes, in the 50's and 60's brakes had a habit of fading through over use and most of the time we did not have servos.

In my auto I sometimes engage the speed limiter to assist in keeping the car below the speed limit, some autos will just keep accelerating down hill under gravity using the highest gear available, more modern autos, and certainly my experience with CVT boxes tend not to do this and will use engine braking.

I guess there is no right or wrong way to drive down hill short of driving like a maniac to see how fast you can go :D
Past cars Mercedes B Class, S Class, E Class Estate, E Class Coupe, G Wagen, 260E interspersed with Peugeot 406 and Audi Coupe.
Deleted User 3871

Post by Deleted User 3871 »

I'm agreeing all the way here, Just adding a little to the braking with "with CVT boxes tend not to do this and will use engine braking. "

The BMW M140i I previously owned could apply the brakes when going downhill on cruise control where the engine was not able to keep the speed within 1 or 2mph. Quite a fancy setup that was a tad annoying as I usually allow the car to speed up some to gain the maximum benefit from going down a hill. So going down steep hills I would disengage cruise as I did not want the car breaking for me.

Qashowner wrote: Sun Dec 05, 2021 5:53 pm From reading most of the above, I think it depends on how old we are. I am 70 and was taught totally differently on the use of gears than my children. For example, approaching a junction we were taught to change down through the gears so we were in the rights gear to pull away if the road was clear, my children mutter on about block changing, but they are happy to drive my auto :D

Driving down hill we were taught to use a low gear and not rely on the brakes, in the 50's and 60's brakes had a habit of fading through over use and most of the time we did not have servos.

In my auto I sometimes engage the speed limiter to assist in keeping the car below the speed limit, some autos will just keep accelerating down hill under gravity using the highest gear available, more modern autos, and certainly my experience with CVT boxes tend not to do this and will use engine braking.

I guess there is no right or wrong way to drive down hill short of driving like a maniac to see how fast you can go :D
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