Good Example of live axle suspension at speed...

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lax2wlg
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Good Example of live axle suspension at speed...

Postby lax2wlg » Thu Nov 20, 2014 2:18 am

Last edited by lax2wlg on Thu Nov 20, 2014 3:10 am, edited 1 time in total.
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lax2wlg
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Re: Good Example of live axle suspension at speed...

Postby lax2wlg » Thu Nov 20, 2014 2:23 am

As opposed to

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Re: Good Example of live axle suspension at speed...

Postby J_Dub » Thu Nov 20, 2014 5:53 am

All that showed was 2 different vehicles, 2 different drivers on 2 different tracks, with 2 different sets of tyres

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Re: Good Example of live axle suspension at speed...

Postby lax2wlg » Thu Nov 20, 2014 7:03 am

Yes thats true, I think it kind of illustrates how (at speed) unsprung weight can lead to a loss of control.

Conversely if you compared the two vehicles in a rock garden section, the IFS FJ Cruiser would come off second best. Although they have quite a clever factory traction system called A-TRAC which sort of mimics locking differentials.

Certainly there are people out there who can get a solid axle to work reasonably well at speed.

Maybe I am wrong.

I thought it was just an interesting comparo of relatively stock vehicles.

In any event the Disco V8 sounds great as it tears itself back onto the track.
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Re: Good Example of live axle suspension at speed...

Postby derk » Thu Nov 20, 2014 7:05 am

whats the moral..... don't buy a landy :D

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lax2wlg
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Re: Good Example of live axle suspension at speed...

Postby lax2wlg » Thu Nov 20, 2014 7:09 am

derk wrote:whats the moral..... don't buy a landy :D

:lol:
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slide
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Re: Good Example of live axle suspension at speed...

Postby slide » Thu Nov 20, 2014 7:15 am

I can see the differences.
The disco was set a low ride height, spring rates would have to be set quite hard to stop constant hitting bumpstops. That wouldn't help with already high unsprung weight, and possible what gives it the real bounce (seen well when driving away from tree)
The cruiser at 13-14 seconds in shows how independent suspension really is independent.
Only two observations with making direct comparisons

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Re: Good Example of live axle suspension at speed...

Postby churchill » Thu Nov 20, 2014 7:58 am

I was the BOP round of the national trials and there was a couple of full independent suspension trucks there. One had Hummer portal axles and a LS engine of some sort and what suprised me was how well it climbed hills. Solid axles with a panhard rod was not as good as the independent suspension on the steep rutty stuff, the geometry is all wrong and the unsprung mass is way to high to be able to keep the wheels on the ground effectively. Sidelings were a struggle for the independent suspension though, something to do with the roll centre by the looks of it.

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Re: Good Example of live axle suspension at speed...

Postby Gyxx » Thu Nov 20, 2014 10:16 am

I don't want to wade into the whole live axle vs IRS debate because it's been done to death and often it's not comparing apples with apples though I will make 2 observations: Firstly - How often do you ever see a purpose built off-road racer (not a factory modified production special or homologation model) these days use anything but heavy duty independent suspension all round? Having said that equating the heavy-duty IRS under the front of a Baja racer with the IRS under a standard production 4WD is kinda like saying a chicken and a human are the same thing because they both walk on 2 legs. Secondly - How often to you ever see an off-road racer (I'm talking the Paris-Daker and Baja vehicles here not the Woodhill specials) trying to articulate it's wheels up around it's ears on a 'real' 4WD track? The point being they're different vehicles designed to perform well in different conditions.

Regards the unsprung mass issue it's a pretty straight equation that (all other thing being equal - spring rates etc...) suspension 'performance' can be described as a pretty straight ratio between sprung and unsprung mass. Anyone who's ever raced road bikes and been fortunate enough to be able to splurge out on some really expensive super-light wheels will testify as to how much reducing the unsprung mass has improved the suspension compliance.

Having said all that I must confess that I'm a boring old fart who's quite happy to plod along at a moderate pace (in my solid-axled old dinosaur)and just get where I'm going with the minimum of fuss and breakages. The days of sending great rooster-tails of mud into the sky and coming home in a vehicle that looks like a Tyrannosaurus took a dump on it are behind me. That is of course unless I face an obstacle that only a bit of momentum and wheel-spinning will get me past. When I finally pull finger and get the GSXR back on the road I'm sure the youthful joy of unnecessarily turning rubber into air pollution and sucking up the planet's remaining hydrocarbons at the greatest rate possible will return to me. Until then I'm more concerned about remembering where I packed the Thermos than getting there quickly.

Thanks for posting the awesome vids dude. I just hope some kind, caring person gave that poor tree a big ol' hug after the nasty Land Rover took a chunk out of it ;-)...

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Re: Good Example of live axle suspension at speed...

Postby 4WDbits » Thu Nov 20, 2014 5:58 pm

Here is a better side by side suspension comparison
https://www.facebook.com/4WDbits/posts/836132666409658?notif_t=like

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