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Ricky Chianese



Member Since: 15 May 2009
Location: Perth
Posts: 10

Australia 2008 Defender 110 Puma 2.4 SW Stornoway Grey
Puma Centre Diff Lock Max Speed?
Anyone out there know why the manual says that diff lock is not to be used above 60 Km/hr?

Has anyone done more than 60 Km/hr with centre diff locked on dirt roads without any adverse effects or drive line damage?

In my old TDI, I used to do around 80-85 Km/hr on good dirt roads with the centre diff locked as the vehicle appeared to have better stability especially on long swept corners.

Any comments out there?

Cheers Why do today what you can put off until tomorrow?
Post #39087 26th Aug 2010 4:38am
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AndrewS



Member Since: 10 Apr 2007
Location: Hereford
Posts: 3707

United Kingdom 2013 Defender 130 Puma 2.2 SW Rimini Red
Its probably down to Land Rover covering their asses, therefore if something goes wrong ie you crash as the vehicle wont turn as easy with the centre diff locked they are not to blame. 130's have feeling's as well you know Smile
Post #39092 26th Aug 2010 7:14am
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MK



Member Since: 28 Aug 2008
Location: Santiago
Posts: 2414

Chile 2007 Defender 110 Puma 2.4 SW Chawton White
I did it when I had the front propshaft off for a while. Apparently no problem. Puma 110" SW

.............................................................
Earth first. Other planets later
Post #39102 26th Aug 2010 10:20am
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jst



Member Since: 14 Jan 2008
Location: Taunton
Posts: 8020

 2011 Defender 110 Puma 2.4 USW Stornoway Grey
i reckon its as Andrew says, there is no mechanical reason why it should be speed limited that i am aware of. Cheers

James
110 2012 XS Utility
130 2011 M57 bespoke Camper
90 2010 Hardtop
90 M57 1988 Hardtop
Post #39105 26th Aug 2010 10:47am
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Naks



Member Since: 27 Jan 2009
Location: Stellenbosch, ZA
Posts: 2638

South Africa 2010 Defender 90 Puma 2.4 SW Alpine White
Re: Puma Centre Diff Lock Max Speed?
Ricky Chianese wrote:
Anyone out there know why the manual says that diff lock is not to be used above 60 Km/hr?
Has anyone done more than 60 Km/hr with centre diff locked on dirt roads without any adverse effects or drive line damage?


Did 4000km trip to the Kgalagadi recently, about 1500km of that on gravel roads in the park, all with CDL locked, mostly pottering around at 60kmh.

On normal gravel roads I drive with CDL locked up to 110kmh sometimes, never had any issues, whether on my Td5 or now on the Puma. Thumbs Up
Post #39107 26th Aug 2010 11:04am
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KarlB



Member Since: 08 Feb 2010
Location: Canberra
Posts: 91

Australia 2010 Defender 90 Puma 2.4 XS CSW Rimini Red
To my mind Ricky, the question is why would you want to drive at high speed with the diff locked? You will certainly wear your tyres out faster and put unnecessary strain on your drive train. It is also likely to be less safe with a greater likely hood of the font or rear breaking away as the front/rear wheels need to travel at different speeds through corners. If they can’t travel at different speeds then you either get transmission wind-up or wheel skid. Most of the time this may be an insignificant issue but you only need to have a problem once and you could loose control of the vehicle and the consequence of that may not be nice to contemplate.

Cheers
KarlB
Post #39114 26th Aug 2010 11:24am
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Ricky Chianese



Member Since: 15 May 2009
Location: Perth
Posts: 10

Australia 2008 Defender 110 Puma 2.4 SW Stornoway Grey
KarlB

I agree that excessive speed is asking for trouble especially on dirt roads - done 1000s of kms through Namabia's dirt road infrastrcture in the past. Doing 110 km/hr on their dirt roads can be smoother than 80Km/hr on many sealed roads I have been on in the past. The Defender - even older models can give you a false sense of security as they travel so well over uneven surfaces that lesser vehicles (everything that is not a Defender) can only dream of. To understand this, just ride behind another 4WD and watch the occupants heads bob around like noddy.

I generally do not to do more than 85 Km/hr or so as it is the stopping bit that I worry about - you never know - tyre blow-out, stray domestic stock, wash-outs hiding in shadows etc. Even at 80 odd Km/hr, I have managed to hit a few chickens, goats, cows, cats, geep, sheep and one two legged creature that is not a bird! - better not go any faster then hey!

Anyway, thanks for your comments, much appreciated.javascript:emoticon('Mr. Green') Why do today what you can put off until tomorrow?
Post #39119 26th Aug 2010 12:11pm
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MK



Member Since: 28 Aug 2008
Location: Santiago
Posts: 2414

Chile 2007 Defender 110 Puma 2.4 SW Chawton White
Once a One10 V8 had some bolts flying away of the central diff. Puma 110" SW

.............................................................
Earth first. Other planets later
Post #39162 26th Aug 2010 7:33pm
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David128



Member Since: 31 Jan 2010
Location: Melbourne
Posts: 30

Australia 2015 Defender 110 Puma 2.2 CSW Zermatt Silver
I use the centre diff lock at any speed provided the surface is loose, the wheels are travelling at the same speed & I going in a straight line. Generally I do not go above 80 kmh on dirt roads. I have done this with all Land Rovers.

I feel safer with both axles getting equal drive as opposed to all drive going to one wheel on a poor road surface or bad corrugations.
Post #40395 13th Sep 2010 12:01pm
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David128



Member Since: 31 Jan 2010
Location: Melbourne
Posts: 30

Australia 2015 Defender 110 Puma 2.2 CSW Zermatt Silver
I use the centre diff lock at any speed provided the surface is loose, the wheels are travelling at the same speed & I going in a straight line. Generally I do not go above 80 kmh on dirt roads. I have done this with all Land Rovers.

I feel safer with both axles getting equal drive as opposed to all drive going to one wheel on a poor road surface or bad corrugations.
Post #40396 13th Sep 2010 12:10pm
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JoostKenya



Member Since: 31 Jan 2010
Location: Naivasha
Posts: 9

Kenya 
That concept of “equal drive” is a misunderstanding of physics.

If the diffs are un-locked every wheel is getting the same torque / drive force. The speed of the output shafts are variable and adjust each other to the corner. Vehicle dynamics will be predictable.

If the diffs are mechanically locked the speeds of the output shafts are the same but the torque / drive force is unpredictable!
The drive force will be dependent on the road surface conditions and may be different on all four wheels. This could potentially make it tricky to recover a vehicle from an instable driving situation (heavy oversteer) with the centre diff locked. Driving forces are disturbing lateral tyre forces and the yaw motion.

Based on the previous I don’t see a benefit of locking the differential at high speed. I only see a higher risk of accidents, more tyre wear and strain in the drive train.

But maybe locking can introduce some extra damping on the yaw-motion because of the additional friction losses when cornering reducing overshoot. Maybe that is the benefit people are finding.
Let me find out on our dirt roads in Kenya. Joost
Defender 110 Puma 2.4
Tornado TD5 Racer
Defender 110 V8
Defender 136'' 300Tdi Safaricar
SIIA V8 Hybrid
Post #40413 13th Sep 2010 4:40pm
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MK



Member Since: 28 Aug 2008
Location: Santiago
Posts: 2414

Chile 2007 Defender 110 Puma 2.4 SW Chawton White
What he said ^^^^^^^^^^^^ Thumbs Up Puma 110" SW

.............................................................
Earth first. Other planets later
Post #40433 13th Sep 2010 7:58pm
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Naks



Member Since: 27 Jan 2009
Location: Stellenbosch, ZA
Posts: 2638

South Africa 2010 Defender 90 Puma 2.4 SW Alpine White
JoostKenya wrote:
Based on the previous I don’t see a benefit of locking the differential at high speed. Let me find out on our dirt roads in Kenya.


The first rule of LR training is: lock the CDL when you are off sealed surfaces. I find it very strange that you have been driving on dirt roads without locking the CDL Shocked

Personally, I would not drive on any gravel/dirt road without locking the CDL - it makes the vehicle so much more stable, and will actually reduce oversteer.

We should also qualify 'high speed' - I do not drive > 80kmh on gravel roads, no matter how good they are. Doing otherwise is just a recipe for disaster should you encounter an animal, pothole or burst a tyre.
Post #40434 13th Sep 2010 8:06pm
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AndrewS



Member Since: 10 Apr 2007
Location: Hereford
Posts: 3707

United Kingdom 2013 Defender 130 Puma 2.2 SW Rimini Red
Taken from Land Rover Info

CENTRE DIFFERENTIAL LOCK prevents drive being lost to both axles at the same time.

The centre differential lock literally locks out the differential action and forces drive to be split equally between each axle for maximum traction.

So a centre diff lock helps to maintain drive to some of the wheels even if one axle has lost traction.

The centre differential lock should be engaged whenever there is a risk of losing traction.


No expert and each to their own Thumbs Up but I dont see the advantage of locking the CD or any diff at high speeds.

Good thread keep it up Thumbs Up 130's have feeling's as well you know Smile
Post #40503 14th Sep 2010 7:40pm
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MK



Member Since: 28 Aug 2008
Location: Santiago
Posts: 2414

Chile 2007 Defender 110 Puma 2.4 SW Chawton White
What he said ^^^^^^^^^^^^ Puma 110" SW

.............................................................
Earth first. Other planets later
Post #40520 14th Sep 2010 10:24pm
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