Bolt-on 4 Link Kit

[henk]

Found their card:

Gordon Jackson

www.4xforce.co.uk

4xforcebits@gmail.com

01751 430228

York

[elbekko]

I wouldn't trust it from those pictures, and I fully agree with all of Bill's statements about the geometry.

[Cynic-al]

I don't know anything about the design of the kit but I have seen it offroad, it gives a huge amount of flex, especially for something that can be fitted with just spanners. You can argue all day about the plus and minus of any setup but I believe it will appeal to a lot of land rover owners purely because it gives a huge amount of flex for something that can be fitted with just spanners. You've got to praise them for trying to do more than just copy QT which is what so many other manufacturers seem to do. On front axle twist you can see the diff and prop are pretty much in line, this may not be the case on pure drop, I don't know, but how often is that achieved? It can do the 'Spanish axle twisters' at KORC without lifting a wheel which my conventional setup of +5 shocks and cranked arms cannot. That said my joints and arches are not allowing the shocks to reach their full stroke at the moment and both vehicles got through without getting stuck, so meh!

I don't know what springs and shocks this vehicle has but it has the full kit.

It can also be purchased from A&P Land Rover in S****horpe.

[ToyRoverlander]

But I believe it will appeal to a lot of land rover owners purely because it gives a huge amount of flex for something that can be fitted with just spanners.

Flex is useless without decent geometry. LR owners seem to like seeing wheels dangle 3feet under their vehicle and think that's the best thing since sliced bread. Especially at the back...

Dislocated springs as well..... sigh..

Oh well, not my thing. Others will probably buy it and as long as they like it fine with me.

[henk]

I've had the a-frame in hand and to be honest that looked pretty good

[missingsid]

Both A&P and 4xForce websites are waste of space right now.

[ToyRoverlander]

I'd rather have the factory forged (?) a-frame with that indistructable balljoint over someone elses construction of which you know not what wallthickness tube is used and what size those balljoints are. And besides that, that frame does nothing differently than the factory a-frame besides looking different. No advantage whatsoever so why bother.

[Michele]

*edit* Can someone make up a suitable avatar for Bill, with 2000+ posts you would think he should have one by now

Happy to fix it

[uninformed]

I can see some merit in the front design, all be it a large compromise. But the rear set up???? I really think they have gone backwards there.

[Cynic-al]

Flex is useless without decent geometry.

I completely disagree, once you've driven through a puddle to get the bodywork dirty you need to take a photo of it flexing on a rock before taking it home unwashed so your neighbours know how hardcore you are. That's what land rovers are for right?

Sorry, as I said I don't know anything about the design, although I think I read the rear setup was supposed to reduce 'axle steer' whilst flexing? Or maybe I just made that up

[Hybrid_From_Hell]

Nah

Thats wot yer "One life Live Tt" sticker is for

I completely disagree, once you've driven through a puddle to get the bodywork dirty you need to take a photo of it flexing on a rock before taking it home unwashed so your neighbours know how hardcore you are.

[Cynic-al]

Nah

Thats wot yer "One life Live Tt" sticker is for

That must have become acceptable since the recession began, austerity measures and all that

[moose]

(disclaimer) I not a suspension expert far from it... and i commend the guy for doing some thing different.

every one uses their truck differently and i am sure that for some this kit will be fine mainly i see this being used by the playday guys whos truck's never see high range or more than 10mph.

But handling aside I would never fit this to my comp truck, it just wouldn't last the distance from the images posted (as that all i have to go on) i can see lots of points that would fail quite quickly with the usage that my truck sees.

[simonr]

I take on board what everyone has said - but I think it's quite well conceived. I cannot (without data) say anything about the strength or construction.

Any geometry is a compromise and all of them have trade-offs between articulation and handling. Keeping the Panhard rod keeps the steering link moving in a similar arc meaning hydro steer in not a necessity. The two links are well separated, better than most and even with standard A frame ball joints, I think they are not the weakest link.

Assuming the telescopic link in the prop shaft is long enough, the ideal for a correctly phased prop shaft using UJ's is both having the same offset. Then the velocity change in the two joints cancel out. If the offsets are not the same, you can improve the situation by changing the phase of the two UJ's (which is what LR did) - but it's not the correct solution. I suspect that if you used a rear prop on the front, it would be fine (as the UJ's are in phase) or just pull the two halves of the shaft apart at the sliding joint and reconnect in phase.

In the same way as I cannot say if it is strong enough, I don't think any of you can say for certain it isn't!

My biggest concern strength wise would be the axle end link between the top & bottom link where it joins the bottom link. That has the highest stress concentration - by eye anyway. That is not to say however that it is not (or Is) strong enough.

But hell, what do I know!

[simonr]

My biggest concern strength wise would be the axle end link between the top & bottom link where it joins the bottom link. That has the highest stress concentration - by eye anyway. That is not to say however that it is not (or Is) strong enough.

[Edit] Looking at it again, the forces at that point are fairly well balanced as the lower link is below the axle mounting bolt. The main forces the links are subject to are due to acceleration & braking. If you assume you can brake at 2G and only one wheel is in contact with the ground (unrealistic worst case), that gives a torque on the axle of about 20,000Nm - leading to a compressive force of about 7.5 ton on the lower link and 7.5 ton tensile on the top.

This is shared between the links on both sides of the vehicles so 3.25 ton.

Steel is weaker in compression than tension so:

Compressive strength of steel (the links can probably be considered short enough to initially fail compressively rather than through buckling, though they will buckle after) is about 300Mpa or N/mm^2. Assuming the OD of a link is 30mm and the ID is 25mm, they will fail compressively around 64kN or 6.4 Ton.

Therefore the links have a safety factor of about 2 based on the above - but the links may be fatter / thicker wall. For a production item I would prefer a safety factor of at least 6 - but then my force calculation is fairly worst case.

The above is full of assumptions - but I would conclude that the links are (probably) not going to fail as soon as you breath on them and in the event of failure, other things will probably break at the same time!

[landroversforever]

So Simon, when is X-Eng going to release a front suspension package? :-)

[henk]

Why not ask Gordon (the designer) to profile his opinion or is that too easy?

[landroversforever]

I've emailed him for some more information.

[simonr]

So Simon, when is X-Eng going to release a front suspension package? :-)

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

[zim]

In the same way as I cannot say if it is strong enough, I don't think any of you can say for certain it isn't!

I agree with what you said Si, but put those front arms onto an offroad challenge truck that gets abused and i'm pretty sure they'd get bent. LR front arms are tremendously strong and we manage to bend them, now look at the size tubing that's been used above.

G

[Tanuki]

I see suspension-arms with bends in them. I'd really like to know what wall-thickness these arms are, what the material is, and what kind of heat-treatment/stress-relieving they've been through both before & after they got bent.

--S90Dog.

"Give a man a fish and you feed him for a day; Give a man a freshly-charged Electric Eel and he won't bother you ever again".

[henk]

I mailed the guy (no family, no relation or whatever) and I quote:

its made from solid 38mm bright bar not tube and the ball joint is a trackrod end from one of the most popular 44 ton gross HGV's that drive our roads every day

[bishbosh]

I agree with what Si said, (apart from 7.5 divided by 2 being 3.25 )

All the rest of you, well Simon too infact, are missing the whole point about this kit and it has been staring you in the face all along - it is orange and therefore very extreme and very hardcore and will turn your truck into an unstoppable beast.

That is all, case closed. :P

[simonr]

I agree with what Si said, (apart from 7.5 divided by 2 being 3.25 )

Doh!

All the rest of you, well Simon too infact, are missing the whole point about this kit and it has been staring you in the face all along - it is orange

Double Doh!

Si

[simonr]

its made from solid 38mm bright bar not tube and the ball joint is a trackrod end from one of the most popular 44 ton gross HGV's that drive our roads every day

OK, in that case, it will fail around 34 Ton loading - giving a 9x safety factor.

If the ball joint has a diameter of say 25mm where the shaft exits the tapered socket, I estimate will shear at about 98 Ton - so a 27x Safety Factor

This is based on the shaft being 25mm diameter, the shear strength being about 200MPa.

However, it's not in simple shear as the ball is separated from the tapered socket - but it's likely to be a similar number.

The bolts holding the hockey sticks on to the axle will likely fail first (M16). If the rest of the structure has the same kind of safety factor, it will have close to infinite fatigue life too (it may not though).

So, that's probably enough.