Thread: Disappointed in the D5 / waiting for the Defender

Originally Posted by rick130

No, wheel rate is wheel rate.
It doesn't matter a damn whether it's independent, swing, or a beam.
It's easily calculated unless you design a rising rate system, which is a little more complicated to work out, or it can be easily measured.

Bushing design complicates it in all systems, sometimes the bushes are designed to have a certain amount of compliance and can add significantly to roll stiffness, think of an RRC/D1 radius arm front end vs a Deefer, the RRC/D1 use tripple shell bushes which increase roll stiffness significantly, and sometimes it isn't by design either I'd reckon!

Anti roll bars are another complication, adding to single wheel wheel rate and obviously roll resistance.
Their dynamic consideration is lateral load transfer and longitudinal load transfer diagonally across the chassis.

Then we can have anti dive, anti squat, which can change compliance significantly, depending on %'s used in our geometry.
E.g. start lifting the rear of a Deefer/D1/RRC and anti-squat increases significantly which can really impact climbing on rock steps, etc.
Most people that lift a vehicle aren't aware of this.

Roll centres are a dynamic consideration changing longitudinal load transfer as the vehicle rolls.
They won't affect compliance/articulation.

Its significantly harder to redesign a good compromise with a factory independent suspension and not totally **** it all up.
IMO most engineers don't grasp all the conflicting dynamics involved, crunching raw data and dynamic concepts are different, and then it all comes down to which areas are important to the end user and which areas we want to compromise.

Live axles with a kinetic type suspension system would be my ideal, although one day I really want to use custom dampers and driver selectable anti roll bar disconnects, because I many be able to afford that!
There's a couple of shock absorber tricks I learnt many years ago that I don't think have been exploited on a road going 4wd yet.
But they may not work either!

The wheel rate with independent is constant, excluding any anti-roll bar effects or other contrivances.

The wheel rate with a solid axle changes depending on whether only one wheel is moving by itself, or the wheels are moving in different directions to each other, or if both are moving upwards or downwards at the same time.

Originally Posted by rick130

Anti roll bars are another complication, adding to single wheel wheel rate and obviously roll resistance.
Their dynamic consideration is lateral load transfer and longitudinal load transfer diagonally across the chassis.

Its significantly harder to redesign a good compromise with a factory independent suspension and not totally **** it all up.
IMO most engineers don't grasp all the conflicting dynamics involved, crunching raw data and dynamic concepts are different, and then it all comes down to which areas are important to the end user and which areas we want to compromise.

Live axles with a kinetic type suspension system would be my ideal, although one day I really want to use custom dampers and driver selectable anti roll bar disconnects, because I many be able to afford that!

Anti-roll bars only affect the wheel rate when both wheels arent moving in the same direction at the same time and speed. Which is most of the time but not all.

Fully independent with bose full active would be the ultimate, but dont expect them to answer your calls until you put a massive wad in their bank account (?).

Originally Posted by PAT303

Smithy's Rangie wasn't stock. Pat

Rover v8
R380
Lt 230
Maxi drive diffs
Standard springs and shocks
chippa’s Rangie 2 obc’s
Rover v8
R380
Lt 230
Maxi diffs
Yes not stock, but pretty standard
That’s my point to those bagging RRC
As some have already noted good off road doesn’t seem to sell but flash does.
I’ll just drive everywhere on this flat earth with my rv8 and locked live axles, when it’s hot I’ll wind down the window

Forgive my ignorance, but wasn't one of the ideas behind Traction Control, that you didn't need massive wheel travel anymore?
The idea of huge amounts of wheel articulation was to maintain sufficient weight on the wheel to maintain some traction. ETC would seem to negate that need, would it not?

Originally Posted by PAT303

Deano, I've never had a single problem with my modern vehicles in all my outback travel's,but I've met heaps of people with old mechanical vehicles that have.If you get stuck in the bush with a major fault your in trouble,a stuffed water pump bearing,split hose or a collapsed wheel bearing will make any vehicle a desert ornament.It doesn't matter what your drive,it's all about the 5 P's before your go, and the use of common sense once you get there. Pat

Hey Pat, excuse my naivety , but what are the 5Ps??

Originally Posted by PAT303

Deano, I've never had a single problem with my modern vehicles in all my outback travel's,but I've met heaps of people with old mechanical vehicles that have.If you get stuck in the bush with a major fault your in trouble,a stuffed water pump bearing,split hose or a collapsed wheel bearing will make any vehicle a desert ornament.It doesn't matter what your drive,it's all about the 5 P's before your go, and the use of common sense once you get there. Pat

All true Pat, except we all know that the newer and more fancy the Landy, the less likely it is that a local mechanic will be able to / want to help.

But then I guess whoever can afford to take a $100,000 D5 across the country, can also afford to upgrade their vehicle before warranty runs out ...because the back to city base breakdown repair is becoming the only viable option in remote areas for newer vehicles. I'd hate to think what a flat-bed tow from somewhere in the Pilbara or the Gibson, to Perth would cost!

Originally Posted by Hoss

Hey Pat, excuse my naivety , but what are the 5Ps??

Prior Planning Prevents Pi$$ Poor Performance! Ooops! That's 6 Ps, but you get the idea?

Originally Posted by donh54

Forgive my ignorance, but wasn't one of the ideas behind Traction Control, that you didn't need massive wheel travel anymore?
The idea of huge amounts of wheel articulation was to maintain sufficient weight on the wheel to maintain some traction. ETC would seem to negate that need, would it not?

Traction control is a brilliant design concept, using the ABS sensors it senses when a wheel loses traction an applies the brakes to it so that the opposite wheel gains traction (in an opened diff vehicle). A very cheap electronic alternative to an LSD/locker whilst retaining the benefits of an open diff. But it does have its downside. Imagine going up a steep loose terrain slope in an opened diff LR with TC. As the wheels lift or spin the brakes are applied which is the last thing you need to maintain momentum, you will ultimately grind to a halt. There is absolutely NO equal to keeping all four wheels on the ground in off road driving, sure all sorts of fancy electronics can try to compensate but in the end they WILL fail with continual use and you're left with 'failure to proceed'. This is where the RRC absolutely shines with its open diffs and superb suspension travel.

Having said that, on my 2008 crossing of the Simpson Desert (in a D2a) I found that TC was working flat out in the afternoons. This was because the standard factory shocks had 'lost the plot' by lunchtime causing wheel lift (axle tramp) which would normally leave one 'high and dry' but the TC came to the rescue to compensate allowing forward momentum to be maintained With coil springs (which have absolutely zero natural dampening when compared to leaf springs) when you lose a shocker you lose drive on that axle unless you have TC (or a LSD/locker) to compensate.

Deano