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stuart123

Member Since: 03 Apr 2017
Location: Manchester
Posts: 207

2009 Defender 90 Puma 2.4 CSW Aintree Green

Questions on left foot breaking for traction control

I have a 2.4 Puma (with anti-stall, I assume)!

Not used in anger previously but in anticipation of towing a boat along across an area soft sand where I have previously been stuck in an old series lightweight on a slight gradient whilst towing.

Q1.... I've not tried but I think I am right in saying that if I left foot break whilst crawling it won't stall...? If so, should I be gently applying the brakes whilst crossing any soft sand, assuming i'm crawling, in 1st, with diff lock engaged? There is little opportunity in this area to gain any momentum.

Q2- low ratio or high?!

Never tried left foot breaking in the lightweight but will definitely give it a go, but am assuming it is more of an art and more difficult without anti-stall...!

Cheers

Stuart

28th Jun 2017 9:30am

LandRoverAnorak

Member Since: 17 Jul 2011
Location: Surrey
Posts: 11324

Surely the whole point about anti-stall is that it won't stall anyway? There's a well known video of a Puma 90 pulling an artic on gravel at tickover that demonstrates it.

Left foot braking can overcome a spinning wheel to maintain momentum in a non-electrikery equipped vehicle, but will more likely hinder the whole process in a later one. Darren

110 USW BUILD THREAD - EXPEDITION TRAILER - 200tdi 90 BUILD THREAD - SANKEY TRAILER - IG@landroveranorak

"You came in that thing? You're braver than I thought!" - Princess Leia

28th Jun 2017 9:44am

stuart123

Member Since: 03 Apr 2017
Location: Manchester
Posts: 207

Yes, i've seen that video - but nobody is pressing the brake pedal.

If there is a no traction control why would left foot braking hinder the process?

28th Jun 2017 9:53am

blackwolf

Member Since: 03 Nov 2009
Location: South West England
Posts: 17450

2007 Defender 110 Puma 2.4 DCPU Stornoway Grey

The TDCi engine management system knows when the brake pedal is pressed and will behave differently under different condtions.

If you brake hard with no throttle input, the anti-stall will fight the brakes but you can certainly stall the engine (I suspect that after a few second the AS will shut down in this case).
If you brake hard at low speed with throttle input, you can stall the engine more easily.
If you brake at all for more than a few seconds at a speed over 10mph with throttle input, the ECM will cut the throttle input to the engine and you can stall easily.

You can however brake *gently* under any conditions without problems.

it is of course essential that you can stall the engine with the brakes since this may be necessary under emergency conditions, and I suspect that it is a requirement for type approval.

Crawling on soft sand is a good way to get well and truly bogged. Actually, just being on soft sand is a pretty good way to get bogged! How soft is soft?

28th Jun 2017 10:05am

Naks

Member Since: 27 Jan 2009
Location: Stellenbosch, ZA
Posts: 2645

2010 Defender 90 Puma 2.4 SW Alpine White

As far as possible, tow in low range to overcome an obstacle.

I have applied left-foot braking when driving offroad many times, especially in slow & tricky situations where you don't want high rpms and/or wait for the traction control to kick in.

By applying a very light braking, you're just making sure that you have traction at very low speeds/rpm.

But I'm sure you won't need to with the Puma, as long as you deflate tyres down to 1 bar (or even to 0.

for soft sand

--
2010 Defender Puma 90 + BAS remap + Alive IC + Slickshift + Ashcroft ATB rear
2015 Range Rover Sport V8 Supercharged

Defender Puma Workshop Manual: https://bit.ly/2zZ1en9
Discovery 4 Workshop Manual: https://bit.ly/2zXrtKO
Range Rover/Sport L320/L322/L494 Workshop Manual: https://bit.ly/2zc58JQ

28th Jun 2017 1:54pm

discomog

Member Since: 09 May 2015
Location: Notts/Lincs Border
Posts: 2530

2015 Defender 90 Puma 2.2 XS CSW Santorini Black

I was extremely concerned when I read that you were contemplating crossing soft sand whilst crawling. Soft sand is the most difficult terrain to master and can be a beginners nightmare. Soft sand will sap your power and you must at all costs keep the momentum going, left foot braking will reduce the power and consequently your momentum. You also have the added problem of towing a boat and up a slight gradient. You have to ask yourself the question - will the trailer tyres float on the surface of the sand or will they dig themselves in, again this is another reason to keep momentum.

I certainly wouldn't want to be applying the brakes on an incline. A golden rule for soft sand is not to stop and if you do, make sure you are facing downhill. You are also going to have to consider deflating the tyres to improve flotation, down to 1 bar has been suggested above - you can go lower but then you run the risk of the tyre breaking the bead. Also be aware that steering becomes more difficult with ultra low pressures.

I think if I were you, having been stuck once and knowing that you do not have enough space to build up momentum then I'd be looking for another solution. Defender 90XS SW
Mini Countryman Cooper S
Morgan Plus 8

28th Jun 2017 3:15pm

stuart123

Member Since: 03 Apr 2017
Location: Manchester
Posts: 207

blackwolf wrote:
The TDCi engine management system knows when the brake pedal is pressed and will behave differently under different condtions.

If you brake hard with no throttle input, the anti-stall will fight the brakes but you can certainly stall the engine (I suspect that after a few second the AS will shut down in this case).

If you brake hard at low speed with throttle input, you can stall the engine more easily.

If you brake at all for more than a few seconds at a speed over 10mph with throttle input, the ECM will cut the throttle input to the engine and you can stall easily.

You can however brake *gently* under any conditions without problems.

it is of course essential that you can stall the engine with the brakes since this may be necessary under emergency conditions, and I suspect that it is a requirement for type approval.

Crawling on soft sand is a good way to get well and truly bogged. Actually, just being on soft sand is a pretty good way to get bogged! How soft is soft?

Thanks for that, all very helpful. Perhaps might be slightly more than crawling but there's limited area for any extra speed or run up sometime...

The defender stays away from the water but there's a gap between the area of hard sand and tarmac that is inevitably soft and little space for a run up etc.

28th Jun 2017 3:27pm

stuart123

Member Since: 03 Apr 2017
Location: Manchester
Posts: 207

discomog wrote:
I was extremely concerned when I read that you were contemplating crossing soft sand whilst crawling. Soft sand is the most difficult terrain to master and can be a beginners nightmare. Soft sand will sap your power and you must at all costs keep the momentum going, left foot braking will reduce the power and consequently your momentum. You also have the added problem of towing a boat and up a slight gradient. You have to ask yourself the question - will the trailer tyres float on the surface of the sand or will they dig themselves in, again this is another reason to keep momentum.

I certainly wouldn't want to be applying the brakes on an incline. A golden rule for soft sand is not to stop and if you do, make sure you are facing downhill. You are also going to have to consider deflating the tyres to improve flotation, down to 1 bar has been suggested above - you can go lower but then you run the risk of the tyre breaking the bead. Also be aware that steering becomes more difficult with ultra low pressures.

I think if I were you, having been stuck once and knowing that you do not have enough space to build up momentum then I'd be looking for another solution.

Thanks for that. It's not an impossible situation when I go get stuck as there's people around and it's not remote... just recently heard off left foot breaking and wonder whether its something I should be trying in that situation... might be more than crawling but still only going fairly slowly....

Trailer tyres definitely dig in!

28th Jun 2017 3:54pm

Tiger

Member Since: 06 Jul 2012
Location: Wales
Posts: 2265

28th Jun 2017 4:13pm

LR90XS2011

Member Since: 05 Apr 2011
Location: bickenhill
Posts: 3645

2011 Defender 90 Puma 2.4 XS CSW Galway Green

has your defender got traction control?

if so i would have thought low range diff lock and a bit of throttle and it would sort itself out (lower tyre pressure if required) DEFENDER 90 TDCI XS,

I hope everyone is well and your land rovers make you happy

28th Jun 2017 5:08pm

Devon-Rover

Member Since: 22 Jan 2015
Location: South Devon
Posts: 917

2014 Defender 110 Puma 2.2 USW Aintree Green

As already mentioned the key to sand is LOW tyre pressure and a momentum preservation, Anti stall will aid in getting going as the drag in softer sand is quite considerable and towing won't help Whilst not knowing the exact situation and the size of your setup then use of 2nd low with the anti stall to get you moving then building on that to increase speed enough to still have control yet not risk the drag pulling you to a halt.

If you have space then consider using the technique of before traversing a bad patch to go forward and backwards gently a few times in the same spot a vehicle length or three to compress the sand and give you a firmer runway to help in that initial 'launch' as you can accelerate harder then just on virgin sand.

28th Jun 2017 5:53pm

Naks

Member Since: 27 Jan 2009
Location: Stellenbosch, ZA
Posts: 2645

I forgot to add that I only use left-foot braking on rocky obstacles, where precise control and low speeds are required

--
2010 Defender Puma 90 + BAS remap + Alive IC + Slickshift + Ashcroft ATB rear
2015 Range Rover Sport V8 Supercharged

Defender Puma Workshop Manual: https://bit.ly/2zZ1en9
Discovery 4 Workshop Manual: https://bit.ly/2zXrtKO
Range Rover/Sport L320/L322/L494 Workshop Manual: https://bit.ly/2zc58JQ

29th Jun 2017 7:14am

VVS210

Member Since: 12 Nov 2016
Location: Hampshire
Posts: 953

discomog wrote:
I was extremely concerned when I read that you were contemplating crossing soft sand whilst crawling. Soft sand is the most difficult terrain to master and can be a beginners nightmare. Soft sand will sap your power and you must at all costs keep the momentum going, left foot braking will reduce the power and consequently your momentum. You also have the added problem of towing a boat and up a slight gradient. You have to ask yourself the question - will the trailer tyres float on the surface of the sand or will they dig themselves in, again this is another reason to keep momentum.

I certainly wouldn't want to be applying the brakes on an incline. A golden rule for soft sand is not to stop and if you do, make sure you are facing downhill. You are also going to have to consider deflating the tyres to improve flotation, down to 1 bar has been suggested above - you can go lower but then you run the risk of the tyre breaking the bead. Also be aware that steering becomes more difficult with ultra low pressures.

I think if I were you, having been stuck once and knowing that you do not have enough space to build up momentum then I'd be looking for another solution.

What he said + if you feel you have to use low ratio then use 2nd as 1st is just likely to spin the wheels up & dig you in - personally I would use as high a gear as I thought I could get away with & slip the clutch a bit to get things moving. Your boat & trailer will be acting like a huge anchor dragging behind you. Good luck & make sure you post pictures when you're bellied out on the beach...

29th Jun 2017 7:45am

stuart123

Member Since: 03 Apr 2017
Location: Manchester
Posts: 207

Thanks for all the comments! I'm probably making the situation sound really bad - it's not... just wanted to make life a little easier if possible.

LR90XS2011 - I don't have traction control (other than my left foot!!)

Devon-Rover - prefer to leave the tyres pressures normal as it's only a small stretch on soft sand and then the rest is road. Appreciate if I get in a pickle though it's an option! Does anti-stall work in all of the low range box then?

29th Jun 2017 9:25am

blackwolf

Member Since: 03 Nov 2009
Location: South West England
Posts: 17450

Anti-stall works in all gears (12 F, 2 R) but only when there is no throttle input.

29th Jun 2017 11:40am

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