Bolt-on 4 Link Kit

[Hybrid_From_Hell]

^^

Hmmmm

Well then, based on the above I have prob been talking bollox (not unknown) and could well be wrong (also not unknown)

Rather than abuse my position as an admin and sneak in and amend my post I'll just state the above here.

I bow to those who can do the numbers and generate facts vs me and my visual gut feeling which here is proved prob wrong

Considering myself put in me place

[landroversforever]

OOOO someone has made something with thicker steel than Nige

[Hybrid_From_Hell]

Noooo THINNER..............., which is "Not Unusual"

Nige

[bill van snorkle]

But they do do a setup to 4link the rear (Shown in one of the pictures below).

Pictures for you all.

With the bolt on A frame ball mounting, raising the roll centre on a Salisbury diff just requires a spacer and longer bolts. Does this 4 link arrangement offer any significant advantages ?

I have done some articulation experiments with my 100" hybrid, with both standard and lifted rear springs. When the axle, fitted with the softer lower springs articulates, the inner sidewall of the tyre (std 7.50x16s on std offset LWB rims) on the compressed side, rises up and over the upper coil spring mount with clearance. When fitted with lifted springs the sidewall rubs heavily on the outside lip of the spring mount. The problem would be worse with the larger diameter springs of 110" wheelbase vehicles, unless the A frame ball joint was raised the appropriate amount to suit above standard ride height, or rims with sufficient offset to provide clearance.

Deranged. It's just a gut feeling not based on any science, but building in anti dive characteristics by angling the links up from axle to chassis as you suggest would IMO have a detrimental affect on ride quality, and stability under heavy braking.

I am really only questioning the geometry of the system. I personally have no criticism of the construction or material quality of the kit. It looks well made, and if tie rod ends,with tapered pins and sockets are strong enough to withstand the impact forces that steering gear is occasionally subjected to, why wouldn't they be suitable for suspension link ends ? Front propshaft telescopic joint length is not actually where my concern lies. It is the safe UJ angles that could be exceeded by the link geometry keeping a constant pinion angle as the suspension cycles that is my concern. The front prop looks ok in the photo, but that is with the axle articulating ! What about at full droop both sides?

[simonr]

I agree that the rear is a bit pointless and I'm less convinced about the structure of it - but it is a nice shade of Orange.

Si

[De Ranged]

Good point Bill I didn't think about the angle limits of the ball joints if this is extreme flex

As for the reduction in "rear steer" LOL play around on triarged 4 link calculator and you will see that the couple of inches of separation has indeed changed understeer... by a fraction of a degree lol like I said unless you were a race car driver on a track with perfect traction the gain is so minimal as to be undetectable, I'd say worthwhile if your into competition trials or rock crawling this may give you the fraction of an inch better tracking to avoid a peg for a club runner lol na

Arghhh now Bill you are into a whole different thread worth of debate as too how much anti dive is good and personal opinion lol mine is that alot of AD is bad, I like enough that there is some gain from "weight transfer" but not enough that if you slide a wheel, loose that extra brake force and there is a big change in in the height of the vehicle.... handling of the vehicle is more important than maximising one performance, where that cut off is depends on driver skill terrain speed, CoG height, spring rates etc

As for my description that the angle of the links is AD that is over simplified, it is the instant centre versus the wheel base and CoG

Opps I forgot to add that the orange paint does change all this and make it worth while (not as good as yellow tho lol)

[bill van snorkle]

As for my description that the angle of the links is AD that is over simplified, it is the instant centre versus the wheel base and CoG

But, assuming the 4 links of the above kit are actually parallel, then the instant centre of parallel links is infinity, because the projected lines through the links never converge. Without any convergence (instant centre) there is no braking torque induced antidive, or conversely, no drive torque induced front end squat.

The question in my mind I have yet to answer, because I can't find my bleeding compass,protractor and ruler in all this mess is, do unequal length parallel links remain parallel as the suspension cycles from compression to droop ? I'm guessing not, and that at some stage, an instant centre is created. But my minds eye sees the instant centre as being projected several feet in front of the vehicle, which is opposite to what I would think is desirable.

My head hurts now and I'm gonna have a cup of tea and a lie down.

[bill van snorkle]

Happy to fix it

I'll leave it to you to choose from your selection of pics thanks Michele.

[bill van snorkle]

On the subject of rear axle roll/articulation steer, I have mentioned this before on other threads, but I read many years ago an appraisel of the RRC rear suspension design. One point that stood out, in fact the only point I understood at the time, was that rear trailing arm lengths, mounting angles etc were deliberately chosen to give better turn in when cornering, and to counter the forces of severe cross winds. ie the wind force induces body roll which flattens the outside trailing arm angle, and increases the angle of the opposite side trailing arm angle thus causing the vehicle to steer slightly in the direction of the wind.

[4xforce]

Hi all, this is my first post on any forum, i don't usually get involved in discussions like this, but seen as though it involves me directly, i thought i would. Most of the points that are being made from a photo an not actual fact, I'm sure all of us are aware how misleading a photo can be. So I'm not really sure were all this is really leading, im sure from a photo you could have a concern about the wall thickness everyone presumed it was tube (its solid) people are now presuming the rear arms are higher than the LR a-frame when in fact they are as near as dam-it (within 5 or 6 mm) in the same position it just looks different because its not the LR a-frame (looks can be deceiving), the difference is when the axle is at the lower end of the shocker its movement hasn't been restricted by the fact that when a ball joint move's from the middle of its socket it's second axis of movement starts to get restricted, a ball joint only has its maximum movement (what manufacturers quote) when in the centre, when it is at the back of its socket it has considerably less free movement without fouling on the edge of the socket, yes everyone has done it like that for years an it works to an extent, but every thing is that tight when in full articulation it squashes bushes, it also marks the socket an pin with compression bruises were it has been crushed together, has anyone cut a fulcrum ball joint open to look at the damage you get after one weekends use with extended travel shocks and rear arms that don't lock out in the chassis brackets (I'm presuming, no). the EX-ART 4 LINK kit is designed to move freely without any crushing of bushes or damage to ball joints which makes every thing move smother when going over the terrain,when it come to its road manors they are very good indeed due to two things, one because it has ball joint's an normal bushes (an not really soft bushes to compensate for the lack of proper movement when taken past where LR intended) so it has very positive feed back as well as very good control over the axels, two the caster angle stays the same though out the movement from bump stop to 14" of drop which stops the loading of the steering which stops it trying to steer its self when it articulates (ie same as body roll on the road and a god send if you run a heavily off set wheel), making it easy to handle at any speed on the road, I regularly sit at,,,, erm 70,, ish in the fast lane of motorways in my v8 disco without being scared for my life if I hit a cats eye!

Just incase people think this kit is something that has been cobbled together in a shed, it has been in development for over two years by a team with over 60 joint years of experience in several engineering sectors. We also have several other kits in the pipeline, the two kit that were at Peterborough show are just the stock bolt on kits for RRC, disco1 and defender up to but not including the puma,

There will be another editorial by TOR later this year with the defender kit an the challenge kit, I'm hoping this will put to rest any more question of build quality or the pedigree of were it came from but if anyone would like to know any thing about it please feel free to ask rather then just guessing an then having a good old slating session.

If you've got this far without getting board, thanks to tho's who put sensible points across, I'm all for discussion so long as its not a slanging match,

Cheers

Gordon Jackson

4xForce

[Cynic-al]

The question in my mind I have yet to answer, because I can't find my bleeding compass,protractor and ruler in all this mess is, do unequal length parallel links remain parallel as the suspension cycles from compression to droop ? I'm guessing not...

I believe you are correct, as the links are different lengths as they rise / fall the angle of the front mount to the angle of the rear mount will change altering the 'vertical' distance between the pivot points and therefore the angle between the links, but as we do not know any dimensions we can only guess as to the true effect and as always it depends what your hoping to get from it and use it for.

[dirtydiesel]

Hi all, this is my first post on any forum,

If you've got this far without getting board, thanks to tho's who put sensible points across, I'm all for discussion so long as its not a slanging match,

Cheers

Gordon Jackson

4xForce

welcome to Lr4x4 and thank you for joining the discussion

[landroversforever]

Never! My insurance will not cover anything related to the front axle, service brakes and a load of other stuff sadly!

I've made some good ones - for personal consumption!

Si

Such a shame as I'm sure there are some brilliant ideas up your sleeves! I guess the added insurance cost would be mega money! I guess there is no option for you to sell as offroad use only?

The rear set up... would it lessen the binding at the chassis end A frame bushes?

[landroversforever]

Hi all, this is my first post on any forum, i don't usually get involved in discussions like this, but seen as though it involves me directly, i thought i would. Most of the points that are being made from a photo an not actual fact, I'm sure all of us are aware how misleading a photo can be. So I'm not really sure were all this is really leading, im sure from a photo you could have a concern about the wall thickness everyone presumed it was tube (its solid) people are now presuming the rear arms are higher than the LR a-frame when in fact they are as near as dam-it (within 5 or 6 mm) in the same position it just looks different because its not the LR a-frame (looks can be deceiving), the difference is when the axle is at the lower end of the shocker its movement hasn't been restricted by the fact that when a ball joint move's from the middle of its socket it's second axis of movement starts to get restricted, a ball joint only has its maximum movement (what manufacturers quote) when in the centre, when it is at the back of its socket it has considerably less free movement without fouling on the edge of the socket, yes everyone has done it like that for years an it works to an extent, but every thing is that tight when in full articulation it squashes bushes, it also marks the socket an pin with compression bruises were it has been crushed together, has anyone cut a fulcrum ball joint open to look at the damage you get after one weekends use with extended travel shocks and rear arms that don't lock out in the chassis brackets (I'm presuming, no). the EX-ART 4 LINK kit is designed to move freely without any crushing of bushes or damage to ball joints which makes every thing move smother when going over the terrain,when it come to its road manors they are very good indeed due to two things, one because it has ball joint's an normal bushes (an not really soft bushes to compensate for the lack of proper movement when taken past where LR intended) so it has very positive feed back as well as very good control over the axels, two the caster angle stays the same though out the movement from bump stop to 14" of drop which stops the loading of the steering which stops it trying to steer its self when it articulates (ie same as body roll on the road and a god send if you run a heavily off set wheel), making it easy to handle at any speed on the road, I regularly sit at,,,, erm 70,, ish in the fast lane of motorways in my v8 disco without being scared for my life if I hit a cats eye!

Just incase people think this kit is something that has been cobbled together in a shed, it has been in development for over two years by a team with over 60 joint years of experience in several engineering sectors. We also have several other kits in the pipeline, the two kit that were at Peterborough show are just the stock bolt on kits for RRC, disco1 and defender up to but not including the puma,

There will be another editorial by TOR later this year with the defender kit an the challenge kit, I'm hoping this will put to rest any more question of build quality or the pedigree of were it came from but if anyone would like to know any thing about it please feel free to ask rather then just guessing an then having a good old slating session.

If you've got this far without getting board, thanks to tho's who put sensible points across, I'm all for discussion so long as its not a slanging match,

Cheers

Gordon Jackson

4xForce

Welcome to the forum Gordon! Thank you for taking the time to post. Do you know which edition of TOR that will be?

[moose]

My problem with the rear setup is the angle that which the two links converge. Effectively i guess your looking at a single triangulated four link here (again i am not an expert) and the only thing that centres the axle are the top links. The more parallel these top link are the chassis the greater the side loadings are on top axle joints as they try keep the axle in place. This is the reason why the stock a frame ball joint it set vertically in its strongest orientation.

I have found this by my own experience after building my own extended (for a 101" wheel base) a frame and rear trailing arms. As I increased the axle drop travel I was soon destroying the stock ball joints as i was pulling it passed its limit of movement. So I changed to good M24 rose joint and set its orientation to be parallel to the axle. But i soon realized that i was now going passed the limit of the rose joint when fully articulated and on occasion i could push through the centre if the rose joint due to the side loads.

So to combat this I have limited my rear axle travel (7" bump and 8" drop) and used a creeper joint on the a frame that will take big side loading some thing like 14 tons. My set up is a massive compromise (and far from bolt on) but a complete redo from scratch will have to wait for my next truck. I never had any failures of my setup when testing or doing playdays etc... only when competing as this is when you (well i find i do) over driver the truck and do things you would never normally do.

With the front set up i don't like the way the springs dislocate and rest on the shocks. I can only see the shocks in the image with the disco so may be they have been moved? I also think the chassis bracket is way to exposed, the under sides of both my axles after a week of Croatia where polished back to bare metal I can only imagine what those ball joints would be like after blasting through a few good bogs, I have to change the steering joints all the time as rubber gators get ripped away.

I am not having a go this is just why i think this kit would not be for me and of course i can only base my views on what i can see in the pictures.

Paul

[ToyRoverlander]

In this first sentence I wonder what you mean with ball joint damage? What ball joints? From the steering? A radius arm setup doesn't flex anywhere near enough to cause such a problem. Then I wonder whether this was still about the rear a-frame... Your text is a bit confusing to me here. Then you mention caster, making me think you're talking about the front.

the EX-ART 4 LINK kit is designed to move freely without any crushing of bushes or damage to ball joints which makes every thing move smother when going over the terrain,when it come to its road manors they are very good indeed due to two things, one because it has ball joint's an normal bushes (an not really soft bushes to compensate for the lack of proper movement when taken past where LR intended) so it has very positive feed back as well as very good control over the axels, two the caster angle stays the same though out the movement from bump stop to 14" of drop which stops the loading of the steering which stops it trying to steer its self when it articulates (ie same as body roll on the road and a god send if you run a heavily off set wheel), making it easy to handle at any speed on the road, I regularly sit at,,,, erm 70,, ish in the fast lane of motorways in my v8 disco without being scared for my life if I hit a cats eye!

Why would you be concerned about castor with the axle dropped down? Usually when that happens the chassis is hung up on something and you're not moving anyway. It's not like you're driving down the highway with the front raised to max shock extension.

If caster is set correct at ride height it will be stable for sure, no matter what caster it has at full droop. Just not seeing the problem here.

[Cynic-al]

The way I read it, and I could be wrong, is he is referring to the a-frame ball joint damage. I believe what he is saying is a traditional ball joint might allow say (and this is an example figure, I don't know what it actually is) 25 degrees of axle flex either way in the dead centre, however as its a round thing in a road hole if its not in dead centre front to back this figure is reduced down to a theoretical 0 degrees if its at the limit of it's front to back movement. Therefore the 'damage' he is referring to is when you try to get the 25 degrees movement off centre and the edge of the ball hits the edge of the cup.

The best way to picture it in your mind is put a trailer hitch on a tow ball, on dead level ground the hitch can roll side to side, if the car was on a ramp in a multi-story carpark with the trailer on the flat this roll movement about the axis of the hitch would be reduced.

Either that or I've got the wrong end of the stick

Without sticking it all in CAD I'm afraid my mind can't visualise how much of a problem this would cause on a given setup but to go to the effort of making the above which I imagine would make the product more expensive than their competitors I'm guessing they have.

[ToyRoverlander]

I know what you're saying, I kinda got that too from the text. But again, how much of an issue on a Rover with no or a mild lift? The axle doesn't articulate any more (one side up other side down) when the whole axle is at full droop. So that situation hardly ever happens, if it happens at all. Perhaps only with a huge lift when the a-frame is on a steeper angle at ride height. But from what I read earlier in this thread, there are joints available that allow for more movement..

[bill van snorkle]

I join the others in welcoming you aboard Gordon.

I understand your desire to maintain a constant castor angle through the range of suspension travel. Not really certain in my own mind that it is all that important to do so, as the radius arms on my standard RRC handle quite well at speed over the ploughed Macadam that passes for highways over here.

It is also understood that a 4 link system, in order to give the impressive range of articulation that your kit displays, must necessarily have quite parallel links if the bushings/tie rod ends have limited elastic compliance. This leads me back to my concern re front propshaft U joint angles when designing to maintain constant castor. The front propshaft UJ's of the Puma series of Defender over here in OZ at least, due to the steeper mounting angle of the engine/transmission, have on occasion failed, taking out the front of the transfercase as well. And that is with radius arms that are not too concerned with maintaining constant castor, but more with maintaining u joint angles within safe limits. The only way I can see to do that with a non triangulated 4 link is to give some convergence of the projected lines through the links to give an instant centre similar to radius arms. This would also restore a degree of anti dive geometry. But by doing that, one then needs to introduce link bushings with more elastic compliance otherwise articulation will be compromised.

When one looks at the radius arm length and location on the chassis of the original RRC's, one can see that the designers could have made the radius arms much longer if they wished, and the longer arms would have given much greater articulation had that been their main design criteria. But I suspect anti dive under brakes, front end squat under power, roll resistance, resistance to cross winds, under/oversteer, U joint alignment etc were all factors that determined the final design parameters. We can certainly make changes to tailor the system to our own needs. but usually we have compromised one or more of the above characteristics, that in turn require additional modifications to address.

Suspension design is occasionally a fascinating and enjoyable subject for discussion, and it's good to see the various ideas that come up.

Bill.

[discomark10]

Hi allMark this is my first post on any forum, i don't usually get involved in discussions like this, but seen as though it involves me directly, i thought i would. Most of the points that are being made from a photo an not actual fact, I'm sure all of us are aware how misleading a photo can be. So I'm not really sure were all this is really leading, im sure from a photo you could have a concern about the wall thickness everyone presumed it was tube (its solid) people are now presuming the rear arms are higher than the LR a-frame when in fact they are as near as dam-it (within 5 or 6 mm) in the same position it just looks different because its not the LR a-frame (looks can be deceiving), the difference is when the axle is at the lower end of the shocker its movement hasn't been restricted by the fact that when a ball joint move's from the middle of its socket it's second axis of movement starts to get restricted, a ball joint only has its maximum movement (what manufacturers quote) when in the centre, when it is at the back of its socket it has considerably less free movement without fouling on the edge of the socket, yes everyone has done it like that for years an it works to an extent, but every thing is that tight when in full articulation it squashes bushes, it also marks the socket an pin with compression bruises were it has been crushed together, has anyone cut a fulcrum ball joint open to look at the damage you get after one weekends use with extended travel shocks and rear arms that don't lock out in the chassis brackets (I'm presuming, no). the EX-ART 4 LINK kit is designed to move freely without any crushing of bushes or damage to ball joints which makes every thing move smother when going over the terrain,when it come to its road manors they are very good indeed due to two things, one because it has ball joint's an normal bushes (an not really soft bushes to compensate for the lack of proper movement when taken past where LR intended) so it has very positive feed back as well as very good control over the axels, two the caster angle stays the same though out the movement from bump stop to 14" of drop which stops the loading of the steering which stops it trying to steer its self when it articulates (ie same as body roll on the road and a god send if you run a heavily off set wheel), making it easy to handle at any speed on the road, I regularly sit at,,,, erm 70,, ish in the fast lane of motorways in my v8 disco without being scared for my life if I hit a cats eye!

Just incase people think this kit is something that has been cobbled together in a shed, it has been in development for over two years by a team with over 60 joint years of experience in several engineering sectors. We also have several other kits in the pipeline, the two kit that were at Peterborough show are just the stock bolt on kits for RRC, disco1 and defender up to but not including the puma,

There will be another editorial by TOR later this year with the defender kit an the challenge kit, I'm hoping this will put to rest any more question of build quality or the pedigree of were it came from but if anyone would like to know any thing about it please feel free to ask rather then just guessing an then having a good old slating session.

If you've got this far without getting board, thanks to tho's who put sensible points across, I'm all for discussion so long as its not a slanging match,

Cheers

Gordon Jackson

4xForce

Hi Gordon, I wonder if you would consider posting some data on the kit. I think it may usefull to me and others to know what we expect to get from the it in regards to things like anti-drive %, and instant centre, ect.

Cheers Mark

[simonr]

Hi Gordon, I wonder if you would consider posting some data on the kit. I think it may usefull to me and others to know what we expect to get from the it in regards to things like anti-drive %, and instant centre, ect.

While that would be good - there are not many people who understand what they are, let alone how to interpret them. I sometimes wonder if giving too much information can be detrimental when the performance of a product is a compromise between so many competing factors.

I agree that the standard suspension on a Land Rover is a remarkable bit of design for the era in which it was done - but still it doesn't suit everyone and so people modify it, but generally only to extend one extreme of it's functional envelope, usually to the detriment of the other.

Often the best way is just suck it & see - or go on other peoples recommendations & experience. Some of the suspension setups I've tried have looked great in theory - but have been hard to live with in practice. The opposite has equally been true. From this I've learned that no matter how much you know about the mechanics of it, there is no substitute for actually trying it!

Si

[ToyRoverlander]

While that would be good - there are not many people who understand what they are, let alone how to interpret them. I sometimes wonder if giving too much information can be detrimental when the performance of a product is a compromise between so many competing factors.

For the people that do understand that would be nice to know though.

[Chicken Drumstick]

For the people that do understand that would be nice to know though.

I'll happily say I'm no expert and much of this is over my head. However my experience in other things (computer software) tells me, that giving too much info is always bad. As someone will always dislike something about it, even if they couldn't have done better themselves.

Also raw stats often don't mean much without actual context and seeing what something will do.

[Cynic-al]

I believe that's why, for example, ashcroft ran their lockers in various challenge events. With 2 years development I'm sure there is a certain amount they don't want to divulge on an open forum.

[discomark10]

I agree what you're saying, the issue with test and review (unless there is a large number of diffeent ones) is how do you know if the tester knows what they're talking about.

Knowing the facts helps to make an educated decision and for me, it means I'm more likely to go out and buy a major bit of kit like this or QT's 3link.