RE: Land Rover Defender 110 Heritage: Driven

[lostkiwi]

Max_Torque said:

lostkiwi said:

And as I just pointed out, it doesn't matter as long as you have sufficient weight for the voids in the tyre tread to grip something.

what? If you have a cross axle stiffness larger than zero, you CANNOT ever have the same normal load on the pair of tyres on that axle. Back in the day, tractors would have a completely unsprung front axle for that very reason.


Think, properly, about the physical dynamics of the situation.

And as I said earlier it makes no difference if the loadings are not the same.
As long as the tyres have sufficient pressure to push the terrain into the voids the shear strength of the underlying terrain provides drive. The weight of the live axle is not insignificant (hence why the live axle is not ideal on the road) so the reality is that even complete dislocation of the spring will still allow grip to be found.

Max_Torque said:

lostkiwi said:

Have you ever owned and used a 4x4 off road or are you a theoretical 'expert'?

Get you insults in now whilst you have a chance. Read some of my other posts and get back to me on my "expertise"............

Insult? Don't flatter yourself. It was an honest question. Have you ever owned and used a 4x4 off road?
You were after all completely wrong about the articulation of 4x4s hence its a valid question.

[jhonn]

lostkiwi said:

Max_Torque said:

lostkiwi said:

And as I just pointed out, it doesn't matter as long as you have sufficient weight for the voids in the tyre tread to grip something.

what? If you have a cross axle stiffness larger than zero, you CANNOT ever have the same normal load on the pair of tyres on that axle. Back in the day, tractors would have a completely unsprung front axle for that very reason.


Think, properly, about the physical dynamics of the situation.

And as I said earlier it makes no difference if the loadings are not the same.
As long as the tyres have sufficient pressure to push the terrain into the voids the shear strength of the underlying terrain provides drive.

You're both right - an independent suspension will give different wheel loadings under certain conditions, but provided the loading on any individual wheel is sufficient to allow the tyre to bite then traction should be found; it's all down to the depth of the bite and the shear strength of the substrate.

Al least that's what I think you're both saying.

[skyrover]

I think it's fair to say max torque has no experience of proper off-roading, or he would understand the necessity of live axles.

Hence land rover's trick air suspension which mimics a live axle set-up when offroad, but provides the benefits of independent suspension while on the road

[anonymous-user]

Ok, this is my last post on the subject:


Within practical limits, (ie road based passenger 4x4s rather than some extreme rock crawler or what ever. Remember this thread is about defenders!) the type of axle is unimportant, all that matters is cross axles stiffness. if you can't understand that, it's probably why you you are endlessly going on about beam axles and what not. The rest of the world, JLR included, has moved on.

Here's my off road CV:


1990, built my first 4x4, S2a landrover with Ford 2.8 V6.

1992, built 100" hybrid LR (RR chassis, LR body, 4.2 JE V8, warn 8274, and ARB cross axle lockers. Won events such as the welsh hill rally, Numerous trials, and randonee style events etc:

1994: Work for 2 years for a prominant 4x4 specialist, included building numerous class wining AWDC Comp Safari vehicles (and re-engineering the championship winning vehicle in 1994!)

2001: Part of the D3 engineering team at JLR

2008: Part of the 10.5MY PD team at JLR.

2012 onwards: Working with JLR on numerous advanced vehicle projects.



But other than that, you're right, i've no idea what i'm talking about!


Bonus, here's a pic of my hybrid flexing it's axles (and it only got out of this hole thanks to the lockers.........)





For anyone smart enough to understand how important wheel rate is, here is a list of springs, including their rating.


LR_coils

Take a look, then tell me (disregarding any contribution from anti roll bars or suspension link bending) how that effects the load on a tyre with say, 12" of cross axle movement.......

[skyrover]

Spring rate is very important for obvious reasons, as is total articulation distance.

The rest of the world has not "moved on", hence the reasons jeep still offers a live axle on it's newly redesigned wrangler and the Defender replacement will also likely sport live axles.

Toyota also offer a live axle on the front of it's land cruiser.

[lostkiwi]

Ok interesting link to spring rates for various vehicles which shows really only that Defenders are slightly firmer sprung than RRC and Discos which was not a surprise at all (I'm already familiar with that chart).

As far as anything else goes I will stand by what I've said. You're clearly of the opinion that a road going IFS/IRS design can offer more articulation than a live axle and that there are ride height benefits (clearly we disagree on this).

Whilst its also true the D3/D4 are very good off road its also interesting that the Land Rover Experience centres will only take the Defenders on the rougher terrain due to clearance issues (at least thats what the instructor who was teaching my wife said).

IFS/IRS is also far more vulnerable to damage off road than a live axle and more complex to fix. For many thats a serious negative and a reason why some manufacturers (Toyota for example) still offer live axle vehicles in some countries.

So lets just leave it there.

[lostkiwi]

skyrover said:

Spring rate is very important for obvious reasons, as is total articulation distance.

The rest of the world has not "moved on", hence the reasons jeep still offers a live axle on it's newly redesigned wrangler and the Defender replacement will also likely sport live axles.

Toyota also offer a live axle on the front of it's land cruiser.

I'm pretty sure the new Defender will be independent and likely based on the same platform as the Evoque.

[AW111]

skyrover said:

Spring rate is very important for obvious reasons, as is total articulation distance.

The rest of the world has not "moved on", hence the reasons jeep still offers a live axle on it's newly redesigned wrangler and the Defender replacement will also likely sport live axles.

Toyota also offer a live axle on the front of it's land cruiser.

I am not getting caught up in the general argument, but have to point out that manufacturers build what sells, not necessarily what's best. If there is a market for 4x4's with live axles, or 22" rims and liquorice strap tyres, they will sell them, whether or not it's a good idea.

[RoverP6B]

lostkiwi said:

I'm pretty sure the new Defender will be independent and likely based on the same platform as the Evoque.

Which is a now distinctly superannuated Ford EUCD platform tracing its origins back to the Mondeo of 2006 or thereabouts... can't see that staying in production much longer, let alone the Defender using it. They're going to have to replace it with a longitudinal-engined RWD-based platform.

[skyrover]

Discovery chassis based was my estimate.

Already in production, so development costs minimal.

The new discovery will be unitary bodied from what I understand, so the line can possibly be re-purposed.

[lostkiwi]

RoverP6B said:

lostkiwi said:

I'm pretty sure the new Defender will be independent and likely based on the same platform as the Evoque.

Which is a now distinctly superannuated Ford EUCD platform tracing its origins back to the Mondeo of 2006 or thereabouts... can't see that staying in production much longer, let alone the Defender using it. They're going to have to replace it with a longitudinal-engined RWD-based platform.

The Discovery Sport released in 2014 uses the same platform so I'd imagine it will be around a while yet.

[RoverP6B]

I can't see that the Disco Sport is anything but a stop-gap while they migrate to the new compact light alloy rear drive architecture as seen on the XE, F-Pace etc.

[anonymous-user]

I could tell you exactly what they are going to do/use.

But i'd have to kill you all afterwards.


Hmmm, perhaps i should tell you all....... ;-)

[RoverP6B]

[forest172]

uk dealer wanting top money for this example now in the article!!

http://www.autotrader.co.uk/classified/advert/2016...

[KTF]

I wonder what they paid for it.

[AJordan]

As an owner of a late model Defender, I find this trend for wildly rising prices extremely pleasing