Outer Limits 4x4 Board

hello you 4x4nuters i'm new here and relativly new to 4x4s so
here i go, i was messing around with a 3 link calculator to see if i can figure out a way to fit a 3rd link to my front suspension to get rid of the hockey sticks and balance the front end with the rear ,for the record i own a land rover disco1, and after some mesurements of the dimensions of the components and ground distance etc, i realise that the results are not directly translated to common sence my common sence
so if there is someone to explain how to translate the numbers to car performance would be great.i searched the forum and could not find a simple answer to what i'm looking for, every one build their rigs according their requirements/understanding of the fundamentals of suspension design and mechanics.

or a direction to a good topic to start from is also a good idea!!
thnx in advance
daf.

There was a thread recently in the Land Rover forum on pirate 4x4 which explains some of this http://www.pirate4x4.com/forum/showthread.php?t=822569

You will learn a lot on why if you read this. http://www.pirate4x4.com/forum/showthread.php?t=168577
Strange Rover on that thread was one of the founders of the Outerlimits forum.

Shane

thnx a lot boys for confusing me more than before!!
OK i read the most of the pages but things is as i first thought,confusing and the opinions like options many!!!but gave it a go again on the 3 link calculator and got some numbers according to most that i read is good numbers. so here it is
anti squat: 107.94 %
roll axis angle:5.12 deg
roll center height:15.57
instant center x-axis:56.61
instant center z-axis:18.17

is this any good or near acceptable for a 4x4 that the most of the time is spend off road?

With anti-squat it is a matter of opinion and what terrain you drive on, and you driving style.

If you have too much anti squat/anti dive it will bounce and while doing a steep climb this is not good. You could feather the throttle somewhat and you could use limiting straps but in my opinion keep it down to 50% on the front. (I'm no expert, just what I have read and what I have planned for mine)

On the rear, if you are in rocks you might find that the extra anti-squat will actually give you better traction on the rocks, better bite but again if you go too much you either have to go steady on the throtle or fit limiting straps.

Hopefully somone and improve on what I have to say.

Suspension Stuff wrote:With anti-squat it is a matter of opinion and what terrain you drive on, and you driving style.

If you have too much anti squat/anti dive it will bounce and while doing a steep climb this is not good. You could feather the throttle somewhat and you could use limiting straps but in my opinion keep it down to 50% on the front. (I'm no expert, just what I have read and what I have planned for mine)

On the rear, if you are in rocks you might find that the extra anti-squat will actually give you better traction on the rocks, better bite but again if you go too much you either have to go steady on the throtle or fit limiting straps.

Hopefully somone and improve on what I have to say.

Limiting straps won't do anything. And make sure if you do find you have set it up with too much anti-squat, change it before the bouce ends up breaking something. But there certainly is no set rule, and the ultimate setup is certainly open for personal preference and interpretation.

If you set up the limiting strap tight at ride height it will hook you up on the rocks and won't get the chance to hop, this would only work for a pure rock crawling buggy though. It has been done before with great success. Not my cup of tea though.

Speak with this man.
http://www.outerlimits4x4.com/phpBB2/pr ... ofile&u=26

Suspension Stuff wrote:If you set up the limiting strap tight at ride height it will hook you up on the rocks and won't get the chance to hop, this would only work for a pure rock crawling buggy though. It has been done before with great success. Not my cup of tea though.

Mate, speaking from experience here, limiting straps, and/or winches do not stop a hop caused by too much anti-squat. My old boy and I have been through this, and learned the hard way, that if the arm set-up is not correct (within reason), then there is no real way to control the hop. It is not worth chasing ridiculous amouts of drive in herdwick.'s case, for im sure the rig isn't gonna purely see rock.

Safest option IMO, is to chase a 60-80% anti-squat figure, so you can just jump in and drive, without worrying about controlling a hop when you do lose traction.

you dont want to much roll oversteer, ive read even if you can get 0 degrees or in the negative degrees roll understeer is better

Havoc Racing wrote:

Suspension Stuff wrote:If you set up the limiting strap tight at ride height it will hook you up on the rocks and won't get the chance to hop, this would only work for a pure rock crawling buggy though. It has been done before with great success. Not my cup of tea though.

Mate, speaking from experience here, limiting straps, and/or winches do not stop a hop caused by too much anti-squat. My old boy and I have been through this, and learned the hard way, that if the arm set-up is not correct (within reason), then there is no real way to control the hop. It is not worth chasing ridiculous amouts of drive in herdwick.'s case, for im sure the rig isn't gonna purely see rock.

Safest option IMO, is to chase a 60-80% anti-squat figure, so you can just jump in and drive, without worrying about controlling a hop when you do lose traction.

I would aim for less then 50%, you can always increase it.

In the thread I put up as suggested reading it gives an example of a buggy with heaps of anti-squat. This guy had his strap very tight but he won comps with it. I wouldn't recommend it but it is possible to make it work. It is in the 2nd half of the thread. Strange Rover (Sam) was talking about it.

Shane

thnx shane,i'll keep up with sam's posts i think he is realy helpful and he knows the subject,and thnx all of you who gave me some of your time.
i will try to get some pictures of the arm when i finish it and hopefuly till the parts are ready to get enough infos tou make the thing to work!

daf.

herdwick. wrote:thnx a lot boys for confusing me more than before!!
OK i read the most of the pages but things is as i first thought,confusing and the opinions like options many!!!but gave it a go again on the 3 link calculator and got some numbers according to most that i read is good numbers. so here it is
anti squat: 107.94 %
roll axis angle:5.12 deg
roll center height:15.57
instant center x-axis:56.61
instant center z-axis:18.17

is this any good or near acceptable for a 4x4 that the most of the time is spend off road?

remember that on the front of a vehicle, antisquat becomes antidive (braking pushing the nose up or down) but the same rule generally applies. it can make a vehicle handle like shit under brakes and be downright dangerous. ive setup a front 3 link and just kept the same seperation at the chassis as was at the diff and it stayed level under brakes, didnt dive as much as a car but still tipped the nose down a bit.

chunderlicious wrote:

herdwick. wrote:thnx a lot boys for confusing me more than before!!
OK i read the most of the pages but things is as i first thought,confusing and the opinions like options many!!!but gave it a go again on the 3 link calculator and got some numbers according to most that i read is good numbers. so here it is
anti squat: 107.94 %
roll axis angle:5.12 deg
roll center height:15.57
instant center x-axis:56.61
instant center z-axis:18.17

is this any good or near acceptable for a 4x4 that the most of the time is spend off road?

remember that on the front of a vehicle, antisquat becomes antidive (braking pushing the nose up or down) but the same rule generally applies. it can make a vehicle handle like shit under brakes and be downright dangerous. ive setup a front 3 link and just kept the same seperation at the chassis as was at the diff and it stayed level under brakes, didnt dive as much as a car but still tipped the nose down a bit.

Do you know what AS value the front had?

pinkfloyddsotm wrote:you dont want to much roll oversteer, ive read even if you can get 0 degrees or in the negative degrees roll understeer is better

This is pretty well on the mark, squat is not the major factor, weight transfer has more impact on this and static geometry goes out the window when you are climbing a step slope. Is the COG still in the same spot when climbing a slope as to when you worked it out?

While the roll axis determines how the wheels behave in the up and down motion, like when they fall into a hole or hit a step

The other thing to think about is roll centre height; the closer you have your r/c to your COG the less leverage there will be around your roll axis.