Front Flex

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Peter Connan
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Re: Front Flex

Post by Peter Connan » 24 Jan 2013 18:10

Ok, let's continue the blog:

Here is a comparison of the basic systems:
flexassy.jpg
flexassy.jpg (366.68 KiB) Viewed 2288 times
As can be sen, the x-link and double-supaflex layouts give comparable maximum flex. However, I believe the x-link will give better traction. Firstly because the supaflex layout still relies on bushing deflection for suspension flex, and this means that the bushes are fighting you every step of the way, and this reduces the traction on the extended wheel (at the indicated maximum deflection of about 17 degrees, the bushes are fully-flexed (10mm of off-centre on all four bushes), while the x-link's bushing flex at the same articulation is on average 2mm), and also because of axle-wrap and axle-tramp. This is when the axle tries to wrap around it's axis, because the controlling bushes are now much closer together and this motion is undamped. This axle wrap is the reason powerful leaf-spring cars are often fitted with "power bars".

This is maximum flex of my current setup:
flexSTD.jpg
flexSTD.jpg (490.84 KiB) Viewed 2288 times
And this is with an X-link added:
flexX2.jpg
flexX2.jpg (558.02 KiB) Viewed 2288 times
The major concern I still had about the x-link is the process of welding the swivel pin onto the diff. I don't like the idea of this. However I think this might be a suitable altternative: a re-designed diff guard incorporating this swivel pin mounted on a very robust clamp, and also incorporating the lockout hardware.
NPDGX2.jpg
NPDGX2.jpg (275.88 KiB) Viewed 2288 times
This is what my proposed lockout looks like. It is designed to be cable-operated, so that it could even be operated from the driver's seat.
lockout.jpg
lockout.jpg (353.98 KiB) Viewed 2288 times
Mag ons ons kenniskry met lekkerkry aanhoukry.

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Re: Front Flex

Post by Alex Roux » 24 Jan 2013 21:00

Peter

Thanks for this so far. My biggest concern is the overall robustness of the set-up, such as the swivel, and if it proves not ideal, if one can revert back.

I see that you have now opted for the yellow diff guard. Nice!
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Re: Front Flex

Post by Alex Roux » 24 Jan 2013 23:38

Peter Connan wrote:
Kagiso II wrote:Even flex at front and rear results in a better balanced vehicle that is less likely to roll over on a steep but uneven downhill
And this is why the G-wagon with its robust chassis and solid lockers gets to fall over so easily on the more extreme obstacles. Too little flex.
Peter Connan wrote:
Kagiso II wrote:The main advantage of a front locker over added flex is that more flex doesn't really help when the lack of traction is due to factors other than uneven terrain, such as when one wheel is in a mud pool or on ice.
So then in the ideal world, if money is not an issue, is to have both?
And then to use lockers only when really needed?

Peter, when it comes to increasing their front flex, what is the most common route followed by the serious Patrol off roaders in Australia?
Their following is big, and they cannot all be wrong?

Below is the video that Grant added to the previous thread on this topic:
viewtopic.php?f=45&t=2410&p=24912#p24912

http://www.youtube.com/watch?v=WdE-oXCS-YU

I think this GQ also used the xLink system?
http://www.dobbinengineering.com/0463ed ... 77c87.html
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Re: Front Flex

Post by Peter Connan » 25 Jan 2013 07:00

Alex, I have never been there and have only spent limited time on the Auzzy forums, so Grant is probably a better person to answer this post.

However, in Auz the Supaflex and Xlink cost approximately the same(despite the fact that the Xlink is significantly cheaper to manufacture) and the Xlink seems to be much less well-marketed. However, it seems they are fairly equal in terms of vociferous users.

I have yet to see a Patrol with a five-link setup (although I have seen them on Cruiser 80's), and I have yet to see a four-link system on anything that even remotely resembles a road car.

I do believe the X-link as I have drawn it up is at least as robust as the standard setup. Remember that although it is obviously not a straight comparison, the standard bush mounting points are a mere 3mm thick, while the X-link is 10 or 12mm thick. The mount for the swivel is 8mm thick and clamps with 8off M10 bolts...
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Re: Front Flex

Post by Alex Roux » 31 Jan 2013 22:04

Peter

See this video of the green Landy (diff lock) versus the blue Landy (extreme flex) - at 2min 30secs.
Blue landy struggles much more, with loads and loads of flex.
I realise lockers put more stress on the drivetrain and should be used only as a last resort, but from this video it seems that even with lots of flex, there are situations where there is no substitute for lockers.
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Re: Front Flex

Post by Alex Roux » 31 Jan 2013 22:04

Skilpad & Shortie

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Re: Front Flex

Post by Kagiso II » 31 Jan 2013 23:20

Stem niks saam nie 'Lexi -- MOMENTUM is alles - al die anner goed kom tweede.
Sondag het ek daai "bergklim' by Hennops gedoen -- en VERGEET om die difflock aan te swietsj - En Boezman is daar uit, first time met momentum..
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Re: Front Flex

Post by Peter Connan » 01 Feb 2013 06:09

Alex, that blue landy is running out of flex. Furthermore, his flex is all on the rear axle. The result, as can be clearly seen, is that the drooping spring is lifting off it's seat, and thus is not contriduting. The weight resting on that wheel is thus solely a result of the weight on the other rear wheel, as it pivots around the compressed spring. And since traction is a factor of contact force... But this will happen.
So yes, for ultimate traction, lockers are better. But thery are also more than five times the price, and I just don't have that much money...
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Re: Front Flex

Post by martyn » 01 Feb 2013 14:24

Hi Peter. Please keep this post updated as it makes for very interesting reading. If you need any help with manufacturing please let me know, maybe I can help somehow.
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Re: Front Flex

Post by Grant » 01 Feb 2013 14:53

Alex

Extreme articulation is only good at keeping the tyre on the ground. As Peter has said you also need weight on it to prevent traction loss. Patrols have an advantage of being heavy vehicles and our diesels have lots of torque on the bottom end.

Was looking at this option but after our road trip I have realised, that firstly I am an overlander, and secondly a 4x4 er. Spoke to a couple of friends down under and front locker is by far the most popular.

Aussie has restrictions on lift and tyre size.


My choice would be the locker.

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