Author Topic: Independent Rear Suspension  (Read 4398 times)

Offline rockmonkey69

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Independent Rear Suspension
« on: 11 October 2012, 00:48 »
Has anyone made their own independent rear suspension setup for the mk4 without going 4wd or using the haldex rear end?
I've got plenty of adjustment in my front custom tubular wishbones but would like the same level of adjustment on my rear and have anticipated having one made, although I've a rough idea of how it might look it would be nice to have some more input from others that have converted the rear end of the mk4 golf.

Below is my print out, the front camber still needed adjusting but it does emphasise my need for more adjustability on the rear.

Offline Prawny

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Re: Independent Rear Suspension
« Reply #1 on: 11 October 2012, 11:39 »
What exactly are you wanting to achieve by making the rear end more adjustable?

Your geo settings are incredibly tame at the moment, pretty much standard all round, so there's huge room for improvement there.

If you've got adjustable wishbones, I'd be looking to wind on as much caster as you can up front, more like 9-10 degrees, and for camber You'd be better aiming for closer to 3 degrees negative rather than the 1 degree it's at currently.

As for the rear, what's your main concern? You've currently got a decent and square looking rear beam, I'd be looking to decide what geo you want at the back, and start by trying shims to get to where you want to be. I've got a set of shims to go on mine at the moment which will cancel the rear toe to zero (parallel), and increase the rear camber to -2.2 degrees, I'm coupling this with what I hope to be 2.8-3 degrees camber up front and around 10 degrees caster.

Caster is what really changes these cars and makes huge improvements, and at 6.5 degrees, you're REALLY missing out!

Do you also have TT/S3/R32 spec front hubs to correct the roll centre?

Offline Wazzzer

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Re: Independent Rear Suspension
« Reply #2 on: 11 October 2012, 12:36 »
Would also like to know what the best settings are for a road car so I can get mine set up properly later


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Offline rockmonkey69

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Re: Independent Rear Suspension
« Reply #3 on: 11 October 2012, 12:38 »
Standard caster on a mk4 is ~1.5 degrees, I have 6.5 with 2mm adjustment on the wishbones. I do need to adjust the camber slightly but I don't want to compromise on straight line traction too much or destroy my tyres as it's used as a daily too. I don't like the idea of shims as adjustability isn't there, it's a case of what you get is what you get.

Offline rockmonkey69

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Re: Independent Rear Suspension
« Reply #4 on: 11 October 2012, 12:53 »
Would also like to know what the best settings are for a road car so I can get mine set up properly later

Depends on your preference and the type of driving your doing but it's accepted more caster is better. On that note the standard mk4 does not have much adjustment.

On a side note I have tried maxing my caster before and encountered rubbing before I maxed out the adjustment on the heim, it ran about 16 degrees when the wheel started touching the front bumper. How do people get around this? Removing the arch liner wont help in my case either because I have quite a bit of poke so I can't get the wheels to tuck inside the arch.

I think I'll increase the camber to 2.0 and give it a few hundred miles to see if I'm fine with the wear.
« Last Edit: 11 October 2012, 13:03 by rockmonkey69 »

Offline Prawny

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Re: Independent Rear Suspension
« Reply #5 on: 11 October 2012, 13:51 »
Standard mk4 caster isn't 1.5 degrees, it's around 5-5.5. 6.5 is still nowhere near enough to make a mk4 handle properly.




On a side note I have tried maxing my caster before and encountered rubbing before I maxed out the adjustment on the heim, it ran about 16 degrees when the wheel started touching the front bumper. How do people get around this? Removing the arch liner wont help in my case either because I have quite a bit of poke so I can't get the wheels to tuck inside the arch.


the answer is, move the top back. Rather than doing all your adjustment at the bottom pushing it forward, get some adjustable top mounts and pull the top back a similar amount, same goes for camber too, if you do all your adding at the bottom you'll eventually run into driveshaft length issues, pulling it in at the top a similar amount will avoid that.

I think you need to decide exactly what it is that you want. Talking about IRS and tubular wishbones suggests that handling is everything and the main goal, but talking about tyre wear and silly wheels that don't fit properly suggests otherwise  :tongue:

As for shims, I don't see a great problem. adjustable suspension geometry isn't something you change regularly, you find the sweet spot and stick with it.

If you start with a measured base line - as you have from your stock print out, and then shim it to the point you want, it's fixed, and won't change. shims being a fixed value are also easily swapped out to make changes for things like weather (assuming you're worried about adjustability for that kind of reason). It may take you a few attempts to get to something you're happy with, but once you're there you're unlikely to change it again.

Perhaps an easier and more worth while investment into the rear end would be to triangulate the rear beam like the beetle RSI with rose jointed tie bars and turrets behind the stub axles, this stops the toe and camber changing when it flexes under load, a bit like this:

[img]http://i74.photobucket.com/albums/i273/Chris_Eyre/Reeves%20Mk1%20rebuild/IMG_0231.jpg[img]




Offline rockmonkey69

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Re: Independent Rear Suspension
« Reply #6 on: 11 October 2012, 14:12 »
Short of shaving the wheels down and downgrading my brakes to LCR or r32 brakes I need to have a little poke for this setup unfortunately. But they fit and while they are legal and I do exaggerate the poke it still won't tuck under the bumper.

Tyre wear is an issue for me because I use my car as a daily too and I run AD08 on the road and A048 on the track so can't afford to be running any aggressive camber permenantly. I switch between tyres and geometry setup for any sessions on the track. So it's nice to be able to have adjustability. Much easier to adjust a heim joint than to remove the rear setup for this, down to personal preference really but I would prefer to adjust heims.

Ps. Turns out the golf does run around 6-7 degrees caster standard! Quite surprised! And yes I think I need adjustment from the top too
« Last Edit: 11 October 2012, 14:19 by rockmonkey69 »