Hi People, hope you're well
So, I was off roading the other night in my freelander and my bro was in his 110, even though he had diff locks, he very nearly got stuck because he hasn't got traction control, unlike my freelander and I didn't nearly get stuck.
Anyway, I am umming and arrrring about what to get (as my freelander is a bit limited), so, to help me decide please could you answer this question:
Does a Disco 2 have traction control?
Thanks
Neil
Just to clarify. Standard "Diff lock" on a Land Rover is the centre differential only.
What this does is allow you have a 4wd vehicle that you can use on the road. As on high traction surfaces like tarmac, you need to let the front and rear wheels spin at different speeds when turning.
The centre diff allows this to happen. But off road an open diff is of limited use, as the power will follow the route of least resistance. So in theory your 4wd vehicle with an open centre and open axle diffs might end up appearing 1wd only, with only one wheel spinning.
Locking the centre diff means the front and rear prop shafts will rotate at the same speed. This means a standard Land Rover will always send power to the front and rear axles. Although with open axle diffs, you can still end up with only 2 wheels spinning. Most commonly seen when you are "cross axled", i.e. have diagonally opposite wheels slightly in the air and spinning.
The centre diff lock only makes the 4wd = to a 2wd/4wd system used by many Japanese trucks when off road. The advantage of the centre diff is 4wd on the road.
The Freelander uses a completely different kind of driveline and is essentially front wheel drive with a viscous unit that will, when the front wheels spin, drive the rear axle. This isn't completely true, as some power is always transmitted to the rear.
The big advantage is the Traction Control. This detects wheel slip and will brake the opposite wheel on the same axle. This has the affect of loading the driveline. A differential will split torque 50:50, but what you need is power to make the wheel rotate. A wheel in the air has no load on it, so an open diff will just 'send' the power to that wheel, making it spin, but as there is little load, there is almost no power being made at the wheels. The wheel on the ground then doesn't have enough power to rotate. The TCS will load the spinning wheel which will make horse power at the wheels, thus the opposite wheel will rotate.
The TCS on the Freelander works very well as it will generally keep all the wheels rotating. So on surfaces like snow, sand or shale. The Freelander has a distinct advantage. The downside is, the independent suspension has limited travel and doesn't flex or keep it's wheels on the ground like a live axle does. This means the Freelander will lift a wheel very easily and will be much more unstable on rutted and uneven terrain. The TCS will keep the wheels spinning, but if you only have 2 wheels on the ground, you will only have limited traction and stability.
A Discovery 1/2 or a Defender use live axles with open diffs. But the live axles allow far more suspension travel. And the key part is, as one wheel is pushed up, it pushes the opposite wheel on the same axle down. This means you keep all the wheels on the ground far more, allowing for more driving traction and more stability.
On slippery surfaces however, keeping 4 wheels on the ground may not be enough to make all 4 spin. But it usually works well enough, especially on uneven terrain.
To give an example of what independent suspension vs a live axle does off road have a look.
Note, this is independent only on the front, so having IRS as well would make it even worse. But look how much more the IFS truck leans vs the live axle one.
Without TCS the Freelander actually wouldn't be very good off road at all. But with it, it makes it highly capable, especially on specific terrain like snow and sand or even a wet grass level field where suspension travel isn't important.
Off road biased TCS fundamentally works differently to road biased TCS systems. On a road car TCS is there to reduce wheel slip, i.e. to stop the wheel spinning. On an off roader the TCS is there to promote traction, by using the wheel slip. Basically you need to keep a few revs on and keep the wheel spinning, as that is the thing that makes the other wheel rotate. It's not a gung-ho approach, but controlled. But timid drivers and people who let off as soon as a wheel spins simply won't get on with traction control.
With regards to the D2. It's driveline is exactly the same as that on a Defender. However introduced with the D2 was a full 4 wheel traction control system. But for some reason Land Rover decided to do away with the centre diff lock.
As I'm sure you've read, some early D2's only need the linkage and I think last of the line ones have the full diff lock system in place. But some model years have a transfer box that is missing more than the linkage. Make sure you read up and price up the bits you think you'll need.
However I would also advise just trying out a D2 when you get one first and see how you get on. Having no diff lock does not mean it isn't capable. It just means you'll have to work it a bit harder and if used excessively off road will eat through brake pads at a high rate.
For example, on you Freelander when the TCS engages it may well only brake one wheel and at most two.
But the D2 with an open centre diff might brake up to 3 wheels at one time and to keep all the wheels spinning will have to work harder, as to promote power on both prop shafts it has to brake an entire axle, not just a single wheel. This means to get it to work well, you have to be a little more aggressive on the throttle and plan ahead a little more, as you may want to induce the TCS before you need it. The TCS is a 'reactive' traction promoter, i.e. it waits until you loose traction before doing anything. A locking differential is a 'proactive' traction promoter and is working before you loose traction.
And there are many other options to consider too. TCS might be seen as a locking axle differential emulation. Which it sort of is, but as said, it is reactive. Fitting something like some torque biasing limited slip differentials to a D2, will massively improve it's traction off road and work brilliantly with the TCS system. You could look at full diff lockers like ARB air lockers, but that would completely negate and by-pass the TCS. I think for most use LSD's + TCS is a better solution.
One other thing to be aware of, the D2 is great and very capable off road. But they do feel quite bulky and it's the body work at most risk. The long front and rear overhangs can cause issues off road too. I'd probably opt for an aftermarket tube type bumper for the front.
