Defender vs Patrol

[Herrie]

I did the Bridgestone Fundi Challenge at Bass Lake last night and at obstacle 9 you go down a hill and you left front wheel must go in to a hole and you must stop when you right rear wheel will be the highest of the ground.

I got ZERO points!!!!

I stopped when i thought that the wheel will lift - it did not!!! I went through the whole obstacle and the wheel never left the ground!!!

The higher you rear wheel left your ground - the more points you get!! This is redicules!!! You need to keep all your wheels on the ground for good traction and this keep you safe. The beter your articulation the more points you should get

[dieselfan]

I got ZERO points!!!!

The higher you rear wheel left your ground - the more points you get!!

So why didn't you ramp?! You'd have all 4 off the ground...you might also find the scuba divers exploring your car

Seriously though I've beginning to see the differences with some of the vehicles and as for the D3 vs HB goes you can see clearly the front left wheel doesn't compress enough in the the wheel arch as the HB does.

I'll be taking both my fathers' D3's offroad soon and hope to do a direct comparison. PS Where is the most sand type obstacles around Gauteng / NW / NP? Ie not too far from Jhb?

[Tinus lotz]

@dieselfan just go to hennops but make sure its wet very wet . Me and piet saw the D3 and Pumas not going up a 1.5 m little slope and that was under the watchful eye of their trainer .At the dam there is some nice twisters to . O yes give me and piet a call to we can take his GQ and my GU and then U can see for yourself

[Peter Connan]

Dieselfan there is very little sand in Gauteng. The only real sand I have come across is at the McCarthy club's grounds, where they have built a sandpit, but you can't just go there and play, as the track is only done under supervision. I think uncle Mac can help you with contact details, but be warned it is not deep or soft enough to really be able to test a vehicle. I drove on it in 2h and with my tires at 1.8 Bar without any problems, and the only way I could get it to dig in was to pull away sharly with the steering on full lock. I have heard that Land Rover in Midrand has a sandpit, and there is probably one at Gerotech, but I have no idea how to get a chance to play there?

Gerrit if you look at that picture carefully you will see that the rear wheel on high ground is actually pushed out further than the one in the hole. This is not a suspension kit's fault but in my opinion can only be a turque effect twisting the suspension. It can probably on only be caused by applieng power on a reasonably grippy surface.

Kobus I had wondered why the Patrol never seems to do well in Fundi Challenge, now I know. How can you penalize a 4x4 for being better than the competition?

[Herrie]

LA Sport in Gezina also have a sandpit!

[Sias]

I did the Bridgestone Fundi Challenge at Bass Lake last night...

Kan enige iemand inskryf op die dag, of moet mens die hele reeks doen en voor af inskryf?

[Gerrit Loubser]

Gerrit if you look at that picture carefully you will see that the rear wheel on high ground is actually pushed out further than the one in the hole. This is not a suspension kit's fault but in my opinion can only be a turque effect twisting the suspension.

I think the strange reaction of the Defender is due to the fact that it is not crawling through the twister like Grant's Patrol, but is being driven through at a higher rate of knots, resulting in some bucking and rocking on the way through.

On the live-axle coil-sprung Landies (Defender, disco 1 and 2, and older Range rovers), the axle is located transversely (side to side) by a triangular member connected to the top of the axle casing by a balljoint. Therefore the roll centre of the rear axle is at this ball joint. This results in a vertical seperation between the torque centre and the roll centre. The effect of this is that when torque is applied through the rear axle, it tries to overturn the vehicle to the right when going forward or to the left when in reverse.

The steeper the hill, therefore the more torque needed, therefore the worse the effect.

On the Patrol, the axle is located by a panhard rod connected on the axle centreline vertically.

Peter, I read your theory, but I don't agree with it.

Let's assume that only the rear axle is in play, to keep things simple (let's say a front wheel has lifted and the center diff is locked, so all drive torque is transmitted via the rear axle).

The driveshaft applies torque (a couple, actually, because the torque is generated without any resultant force in any direction) to the rear axle and an opposite torque (couple) is therefore applied to the transfer case (and hence via the mountings to the chassis). The result would be that the chassis would want to roll relative to the rear axle. This rolling motion is countered by the coil springs and the anti-roll bar (if fitted), not by the A-frame that locates the axle laterally. That A-frame is attached to the axle via a spherical joint, so it can only transmit forces to the axle housing and not torque. This would mean that it could only counter propshaft torque if there were another lateral locating member to provide an equal and opposite force, so that the resultant would be a couple (torque with no resultant force).

Because of the above, it does not really matter whether the axle is laterally located by means of an A-frame or Panhard rod attached above, in line with or below its axis, at least not in terms of body roll on the suspension in response to applied torque.

I hope my explanation is understandable.

[Peter Connan]

Dieselfan this thread seems to be becoming more of a comparison between the Disco3/4 and the Patrol. Both try to reach approximately the same goal, but from opposite starting points. These vehicles are probably two of the most rounded all-purpose 4x4's on the market. There are vehicles on the market better suited to obstacle courses than either, and there are vehicles on the market better suited to driving to your destination.
I doubt though that there are vehicles better suited to loading a family of four and all their camping kit, and then driving to hellandgone over sometimes rough roads and off-road in for example the dunes of the skeleton coast.

The Patrol takes the route of mechanical simpicity. Ladder chassis with live axles on coil springs, part-time 4wd operated by a lever and diff lock for the tough bits, all coupled to a relatively simple engine (at least in 4.8 form) optimised for even torque rather than maximum economy.
The Disco is all about high tech. Independent air suspension and traction control, high tech engines etc.

What follows is purely theoretical, but:
Advantages of independent air suspension versus live axles and coil springs:
1) Lower unsprung mass. This should be used as a factor of total vehicle mass, and in this regard the Disco scores very well, because it is an extremely heavy vehicle. The result of this should be a more comfortable ride and wheels that can react more quickly to high-speed bumps, possibly resulting in better traction.
2) Load-sensitive air suspension as employed in the Disco means that the springs are only as hard as they need to be to carry the load. This should again result in a smoother ride. Metal springs must be designed to carry the maximum load, and therefore are harder than necessary most of the time.

Disadvantages of aindependant air suspension versus live axles and coil springs:
1) Articulation. In independant suspension, the CV joints limit the angle the side shafts can move through, and this in turn limits wheel movement. In the case of the Disco, when the suspension is adjusted to give good ground clearance, the wheel movement is further reduced.
2) Wheel angle. On live axles, the wheels are always approximately perpendicular to the axles, and therefore the wheels remain aprroximately perpendicular to the ground (this one only really works in theory).
3) Underbody protection. In a live-axle vehicle like the Patrol, the diffs are the closest items to the ground, and they are relatively robust. The rest of the vehicle is typically considerably further from the ground. Most of the modern independantly sprung vehicles have relatively flat underbodies, for mostly aerodynamic reasons. Furthermore when the wheels rise over a bump at speed, the vulnerable bits do not rise at the same rate, and so they approach the ground. So while the Disco in theory has more ground clearance, in practise vulnerable bits may well touch ground more often. This is certainly true for the Pajero.

Of course there are a multitude of other factors that can affect all the above arguments. I don't even want to get into arguments about relative reliability, except to say that the more there is to go wrong, the nore opportunity there is for things to go wrong.

[Peter Connan]

I think the strange reaction of the Defender is due to the fact that it is not crawling through the twister like Grant's Patrol, but is being driven through at a higher rate of knots, resulting in some bucking and rocking on the way through.

Gerrit I was not present when this photo was taken, but I have seen Defenders do this before, and speed has nothing to do with it. The worst instance I have seen was a new Defender 90 Puma crawling across a small gully on nearly-flat ground in 1st gear low range. It nearly fell over where the Patrol lifted a wheel about 4".

[Herrie]

Sias, jy moet inskryf vir die hele kompetisie. Al hoekom ek gery het was omdat ons klub se span se bestuurder 'n operasie op sy hand gehad het en nie kom bestuur nie. Ek het die Fundi Challenge in 2007 met my Safari gedoen.