 | Home > Puma (Tdci) > Puma Centre Diff Lock Max Speed? |
 
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| AndrewS Member Since: 10 Apr 2007 Location: Hereford Posts: 3707   
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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
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26th Aug 2010 7:14am |
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| MK Member Since: 28 Aug 2008 Location: Santiago Posts: 2414  
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I did it when I had the front propshaft off for a while. Apparently no problem. Puma 110" SW
............................................................. Earth first. Other planets later |
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26th Aug 2010 10:20am |
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| jst Member Since: 14 Jan 2008 Location: Taunton Posts: 8024  
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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 |
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26th Aug 2010 10:47am |
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| Naks Member Since: 27 Jan 2009 Location: Stellenbosch, ZA Posts: 2638  
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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.  |
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26th Aug 2010 11:04am |
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| KarlB Member Since: 08 Feb 2010 Location: Canberra Posts: 91  
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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 |
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26th Aug 2010 11:24am |
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| Ricky Chianese Member Since: 15 May 2009 Location: Perth Posts: 10 
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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('  ') Why do today what you can put off until tomorrow? |
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26th Aug 2010 12:11pm |
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| MK Member Since: 28 Aug 2008 Location: Santiago Posts: 2414
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Once a One10 V8 had some bolts flying away of the central diff. Puma 110" SW
............................................................. Earth first. Other planets later |
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26th Aug 2010 7:33pm |
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| David128 Member Since: 31 Jan 2010 Location: Melbourne Posts: 30 
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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. |
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13th Sep 2010 12:01pm |
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| David128 Member Since: 31 Jan 2010 Location: Melbourne Posts: 30
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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. |
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13th Sep 2010 12:10pm |
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| JoostKenya Member Since: 31 Jan 2010 Location: Naivasha Posts: 9 
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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 |
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13th Sep 2010 4:40pm |
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| MK Member Since: 28 Aug 2008 Location: Santiago Posts: 2414
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What he said ^^^^^^^^^^^^
Puma 110" SW
............................................................. Earth first. Other planets later |
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13th Sep 2010 7:58pm |
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| Naks Member Since: 27 Jan 2009 Location: Stellenbosch, ZA Posts: 2638
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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 
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. |
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13th Sep 2010 8:06pm |
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| AndrewS Member Since: 10 Apr 2007 Location: Hereford Posts: 3707
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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 but I dont see the advantage of locking the CD or any diff at high speeds.
Good thread keep it up 130's have feeling's as well you know |
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14th Sep 2010 7:40pm |
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| MK Member Since: 28 Aug 2008 Location: Santiago Posts: 2414
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What he said ^^^^^^^^^^^^ Puma 110" SW
............................................................. Earth first. Other planets later |
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14th Sep 2010 10:24pm |
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