How to drive up and down steep mountains in an auto
Discussion
Up, I'm less concerned about (well apart from the distinct lack of power in the Rover) however going down concerns me.
I know typically lower gears are used to maximise engine braking in a manual - does the same principle apply here or will it put the gearbox/torque convertor under excess strain. I'm thinking lock the box in 2(?) (4 spd Auto) and that should be sufficient?
Furthermore, how is it best to apply the brakes. I'm assuming short hard stabs prior to corners rather than more continuous gentle applications to minimise the potential for fade?
Car in question is an auto Rover 820Si.
I know typically lower gears are used to maximise engine braking in a manual - does the same principle apply here or will it put the gearbox/torque convertor under excess strain. I'm thinking lock the box in 2(?) (4 spd Auto) and that should be sufficient?
Furthermore, how is it best to apply the brakes. I'm assuming short hard stabs prior to corners rather than more continuous gentle applications to minimise the potential for fade?
Car in question is an auto Rover 820Si.
yes, use a lower gear, as you would in a manual, to do this just use the "3" "2" "1" options on the gearbox, this forces the box to stay in a lower gear when going downhill, which does stress the torque converter etc, but no more than you would stress the clutch on a manual, and is much better than riding the brakes, then crashing as the hot brakes stop working....
uphill, just use "D" as it will change down as normal, if needs be, slap your foot down so it responds, or if you want you can use the "3" "2" "1" options.
Also "Sport" mode, if it has it, makes it hold onto lower gears for longer, which may be better for uphill!
uphill, just use "D" as it will change down as normal, if needs be, slap your foot down so it responds, or if you want you can use the "3" "2" "1" options.
Also "Sport" mode, if it has it, makes it hold onto lower gears for longer, which may be better for uphill!
Edited by Petrolhead_Rich on Monday 20th September 11:05
Ah. Your post touched a nerve. I've had my clk55 amg since new in 2003 and its performance was great until I tried the one of the steepest of the hairpin bends on Hardknott Pass last year. The road was wet. It's narrow so you don't have a choice of a line to take.... and the car failed to get up/around it. I tried Drive, 2nd and 1st year but I could not get the car to grip and move forward. 
(while other "lesser" front whell ddrive cars passed me).
I had to reverse all the way down/around and back to a please I could turn and find another route (with my tail between my legs)
With regard to braking on down hill sections - low gear + brake in a straight line!
(while other "lesser" front whell ddrive cars passed me).I had to reverse all the way down/around and back to a please I could turn and find another route (with my tail between my legs)
With regard to braking on down hill sections - low gear + brake in a straight line!
g3org3y said:
In terms of the brakes - I'm assuming it is best to brake hard at corners and stay off them all the rest of the time as opposed to continuous medium pressure on the brake all the way down.
I presume you mean brake hard before the corners, not on them. I should have thought that allowing speed to build on the early part of the straights would give you more total energy for the brakes to dissipate - in which case the brakes might overheat sooner, in spite of being allowed some cooling time on the straights. Can a physicist or engineer comment?
In practise, use of lower gears is generally sufficient to control speed on the straights. I have done some swift mountain driving but have hardly ever suffered brake fade on the road since I had a Morris Marina in the 70's.
waremark said:
g3org3y said:
In terms of the brakes - I'm assuming it is best to brake hard at corners and stay off them all the rest of the time as opposed to continuous medium pressure on the brake all the way down.
I presume you mean brake hard before the corners, not on them. I should have thought that allowing speed to build on the early part of the straights would give you more total energy for the brakes to dissipate - in which case the brakes might overheat sooner, in spite of being allowed some cooling time on the straights. Can a physicist or engineer comment?
In practise, use of lower gears is generally sufficient to control speed on the straights. I have done some swift mountain driving but have hardly ever suffered brake fade on the road since I had a Morris Marina in the 70's.
Funnily, the only time I have smelled hot brakes was taking a Marina across the A939 Cockbridge to Tomintoul road, it is a bit hilly, a few years ago we went over that way, and I dropped SWMBO off with her bike for a downhill run, I was following her in the car and she was going over 50mph on some bits!
waremark said:
I should have thought that allowing speed to build on the early part of the straights would give you more total energy for the brakes to dissipate - in which case the brakes might overheat sooner, in spite of being allowed some cooling time on the straights. Can a physicist or engineer comment?
The amount of potential energy that needs to be dissipated is down to gravity acting on the mass of your car over the drop.If you freewheel your brakes will need to dissipate the same amount of energy, as heat, whether you apply a constant drag to maintain a constant speed, brake as hard and as late as possible or anything inbetween.
waremark said:
In practise, use of lower gears is generally sufficient to control speed on the straights. I have done some swift mountain driving but have hardly ever suffered brake fade on the road since I had a Morris Marina in the 70's.
Using a low gear on a trailing throttle means that some of the energy your brakes would otherwise had to deal with is dissipated by drivetrain and pumping losses.Gunning it between hairpins needs big brakes. ...and balls.
g3org3y said:
Up, I'm less concerned about (well apart from the distinct lack of power in the Rover) however going down concerns me.
I know typically lower gears are used to maximise engine braking in a manual - does the same principle apply here or will it put the gearbox/torque convertor under excess strain. I'm thinking lock the box in 2(?) (4 spd Auto) and that should be sufficient?
Furthermore, how is it best to apply the brakes. I'm assuming short hard stabs prior to corners rather than more continuous gentle applications to minimise the potential for fade?
Car in question is an auto Rover 820Si.
If its a big mountain and an old auto box, select a low gear and don't let the car change gear too often on the way up. Hold gears all the way, but just don't let it select gear after gear as you will overheat the gearbox in short order. Trouble with older cars is that their cooling systems are shot for the most part, and everyone always overlooks the cooling for the auto boxes.I know typically lower gears are used to maximise engine braking in a manual - does the same principle apply here or will it put the gearbox/torque convertor under excess strain. I'm thinking lock the box in 2(?) (4 spd Auto) and that should be sufficient?
Furthermore, how is it best to apply the brakes. I'm assuming short hard stabs prior to corners rather than more continuous gentle applications to minimise the potential for fade?
Car in question is an auto Rover 820Si.
On the way down there is no easy answer.
However, if your brakes are below par and you let speed build and you scrub the speed with heavy braking you will probably heat them up much quicker, than if you keep the speed down on the way down.
Also, depending on the state of your front discs and pads will give you some clue as to how to come down the other side. Worn discs (like mine) will have you choking on fumes at the bottom of a mountain even coming down sedately. So wear is a big factor on big declines.
Generally, the moment you smell your brakes you need to calm it down.
tinman0 said:
If its a big mountain and an old auto box, select a low gear and don't let the car change gear too often on the way up. Hold gears all the way, but just don't let it select gear after gear as you will overheat the gearbox in short order. Trouble with older cars is that their cooling systems are shot for the most part, and everyone always overlooks the cooling for the auto boxes.
On the way down there is no easy answer.
However, if your brakes are below par and you let speed build and you scrub the speed with heavy braking you will probably heat them up much quicker, than if you keep the speed down on the way down.
Both wrong.On the way down there is no easy answer.
However, if your brakes are below par and you let speed build and you scrub the speed with heavy braking you will probably heat them up much quicker, than if you keep the speed down on the way down.
Changing gear does not cause heat generation in the gearbox. (Well, not unless the brake bands are way out of adjustment and slip like mad at every change, in which case you'll probably be lucky to get up anyway.) Heat is generated by friction in the gearsets and slip in the torque converter; more heat will be generated in too high a gear as there will be more slip (cf. overheating the transmission by "winding it up" at the lights for a rapid launch). So on the way up, just leave it in D and let it do its job. (Which it will probably interpret as changing into the lowest gear and staying there anyway.)
On the way down, lock it into the lowest gear - it may be necessary to slow right down before it actually changes into the lowest gear, it won't on mine unless you nearly stop - and use intermittent braking. Same as a manual. Coming down something like Porlock Hill in a Morris Minor the brakes will fade with continuous braking, and the way to avoid this is to stay off the brakes and let the speed rise until the noise from the engine and box becomes too grating on the mechanical sympathies and then brake down to a near stand, repeat until you get to the bottom.
Pigeon said:
Changing gear does not cause heat generation in the gearbox. (Well, not unless the brake bands are way out of adjustment and slip like mad at every change, in which case you'll probably be lucky to get up anyway.) Heat is generated by friction in the gearsets and slip in the torque converter; more heat will be generated in too high a gear as there will be more slip (cf. overheating the transmission by "winding it up" at the lights for a rapid launch). So on the way up, just leave it in D and let it do its job. (Which it will probably interpret as changing into the lowest gear and staying there anyway.)
Heat is generated regardless, but leaving it in D on an older car can be asking for trouble, and I know this from experience as I shepherd god knows how many crappy old cars over nearly ever Swiss pass 3-4 times a summer. But hell, what do I know about going over mountain passes and heat?? 
Interesting topic.
I've found the ZF tiptronic box in mine handled the worst Scotland could throw at me very well, locked down no problem, although it could have done with a one and a half gear at times lol.
I too used sports mode for going up very steep hills.
My poor mate, who has a genuine yanky chrysler people carrier warped his front discs, as that car has no lock down facility
I'd also guess that still driving a "modern" rover also deserves some kind of award !
I've found the ZF tiptronic box in mine handled the worst Scotland could throw at me very well, locked down no problem, although it could have done with a one and a half gear at times lol.
I too used sports mode for going up very steep hills.
My poor mate, who has a genuine yanky chrysler people carrier warped his front discs, as that car has no lock down facility
I'd also guess that still driving a "modern" rover also deserves some kind of award !
Modern autos tend to have a torque converter lock up facility above 2,000 rpm to save fuel. Hence you don't get any heat generated.
I have a Croma with the Tiptronic which coped without any drama with all that the Alps and the Dolomites could throw at it last year.
I also used to use it for holding it in gear up hills too as I found it would change gear about 40 yds from a corner or if I had to lift off slightly.
I know your Rover doesn't have tiptronic, but I used to have a V6 Modeo some time ago which had a standard 3 speed auto with overdrive. I used the box in the same way on that and it was ok.
I have a Croma with the Tiptronic which coped without any drama with all that the Alps and the Dolomites could throw at it last year.
I also used to use it for holding it in gear up hills too as I found it would change gear about 40 yds from a corner or if I had to lift off slightly.
I know your Rover doesn't have tiptronic, but I used to have a V6 Modeo some time ago which had a standard 3 speed auto with overdrive. I used the box in the same way on that and it was ok.
Use a lower gear, and if you need to supplement it with the brakes, do so. I'm not sure I'm a fan of the "rush down the hill and stamp on the brakes just before the corners" idea. I would try and control the speed all the way down.
Most modern cars have plenty of spare braking capacity, so don't be concerned about the brakes stopping the car. A good idea would be to change your brake fluid before you go, and check you have plenty of wear left in the discs and pads.
Most modern cars have plenty of spare braking capacity, so don't be concerned about the brakes stopping the car. A good idea would be to change your brake fluid before you go, and check you have plenty of wear left in the discs and pads.
Edited by Mr Grayson on Wednesday 6th October 21:39
Mr Grayson said:
...... A good idea would be to change your brake fluid before you go,
Sorry I have to disagree with that. I am a stickler for keeping my cars maintained, but this is one of the biggest myths perpetrated by the trade to part the motorist with his cash. Yes brake fluid is hydroscopic, but the real danger only lies in areas of very high humidity (and I am talking rain forest type humidity) or if the car is used very infrequently.In 30 odd years of car ownership and nigh on 700,000 miles I have only ever known the water in brake fluid boil once, and that was in 1975 on an 8 year old VW fastback which had been stood idle for two years.
By all means have the brake fluid checked for water content (Kiwik fit will do this as part of their free brake check) but don't go having it changed just for the sake of it.
I live on the coast, and the water content of the fluid in my five year old Croma is only slightly more than when it was a year old.
Before the Croma I kept a Chrysler Neon for seven years and Volvo 850 for 8 years without once changing the brake fluid, and you know what? In the whole time I never even experienced brake fade, let alone failure.
Edited by radlet6 on Wednesday 6th October 22:50
And then jacking the car up, taking off all the wheels, flushing the system etc etc.
Unless you are a competent mechanic this is not a job I would advise anyone to do at home. Plus some of the more complex systems with ABS cannot be bled in the normal fashion and require specialist equipment.
So for most people this job has to be done by a garage at £40 plus vat (minimum). No I don't know about you (and call me tight if you want) but I don't like to spend £40+ every two years without good reason.
Unless you are a competent mechanic this is not a job I would advise anyone to do at home. Plus some of the more complex systems with ABS cannot be bled in the normal fashion and require specialist equipment.
So for most people this job has to be done by a garage at £40 plus vat (minimum). No I don't know about you (and call me tight if you want) but I don't like to spend £40+ every two years without good reason.
Edited by radlet6 on Wednesday 20th October 17:38
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