Qt rose jointed arms

[upnover4x4]

Hi all, Ive had a set of Qt rose jointed arms fitted to my truck for some time now. Crawling under it today I noticed that the top of the arm that attaches to the axle just fore of the rear bush, has been fouling on the bracket that secures the arms to the axle. When I purchased the arms I asked did I need to clearance the bracket to allow for the extended movement of the arms to stop any fouling & I was informed "NO". I know the solution to cure the problem is to just grind the bracket out slightly to allow the axle to rotate fully, but what Im curious of is has any body else had to do so?Is this kind of normal practice to have to clearance the brackets to get full rotaion of the axle whilst the axles moving downwards & forwards?

Adrian

[ciderman]

Adrian , Just out of interest how are the rose joints copeing on the chassis end? I nearly bought a set of these last year , But I was advised against them , Reason was there was no bush to take the shock load from the axle to the chassis and therefore could cause cracking on the chassis member . But I havent actualy seen anyone that has a set to comment about them .

Jase

[upnover4x4]

Adrian , Just out of interest how are the rose joints copeing on the chassis end? I nearly bought a set of these last year , But I was advised against them , Reason was there was no bush to take the shock load from the axle to the chassis and therefore could cause cracking on the chassis member . But I havent actualy seen anyone that has a set to comment about them .

Jase

Dont seem to have any signs of fatigue,cracking or distortion to any of the fixing points. The 1 thing I will say is that theres probably a bit more play in the rose joint than I would like,bearing in mind that theyve only been fitted a year but thats probably acceptable for the amount of abuse it recieved. Unfortunately theres no provision to lubricate them, need to be removed & greased accasionally which is a pain. With hind sight having had them fitted for a while Id have rather bought a set of giglepin arms.

I cant say ive noticed any difference in the ride quality as ive heard a few people mention that rose joints can be a bit harse compared to johnny joints etc.

Ade

[SteveG]

With hind sight having had them fitted for a while Id have rather bought a set of giglepin arms.

or better still a set of X-Arms

[upnover4x4]

steve, have you had to clearance your brackets?

Adrian

[Steve 90]

or better still a set of X-Arms

Better? Matter of opinion. Both jims and si's are excellent products but cant see you can say they are better! I have Gigglepins, I love them and would take a lot of convincing to change to anything else.

Back to the original question. The rose jointed arms in them selves would not cause you to need to notch the axle brackets as they will only give you the same amount of travel as before just a smother movement within that range. So if you didn't need them notched before then you shouldn't after. The travel in the shock absorber is what controls the amount of travel and if you have long shocks its quite common to have to notch the axle brackets. I think a plus 2 inch shock is just about OK but anything more will need notching.

[simonr]

All three products are pretty good and each has their own plus and minus points. No one product can be all things to all men! I would not therefore want to call which is the best as it is subjective.

Also as I find time & time again, a product which fits one vehicle without problems might not fit another at all due to subtle changes in model years and tolerance. You may have clearance issues even though QT did not when they tested it.

I think with most 4x4's you just have to accept that a bit of fettling might be necessary sometimes.

Si

[upnover4x4]

Back to the original question. The rose jointed arms in them selves would not cause you to need to notch the axle brackets as they will only give you the same amount of travel as before just a smother movement within that range. So if you didn't need them notched before then you shouldn't after. The travel in the shock absorber is what controls the amount of travel and if you have long shocks its quite common to have to notch the axle brackets. I think a plus 2 inch shock is just about OK but anything more will need notching.

I recently renewed my rear axle & when doing so I made an assumption that the brackets were actually clearanced more than my old axle. I knew I had clearance issues before on the old axle.

Im running 15" dampers on the rear in the form of Scrapiron racing. I think ill clearance the bracket & see if that allows the axle to rotate fully & let the axle "walk" fwd without catching on the bracketry. QT arms are rather bulky looking compared to X-eng & others I have seen, as Qts use of the "C" shape section for construction. If you look at the pic attached you can just make out where the arms been damaged by the bracket.

[simonr]

Many Land Rovers have a scallop taken out of the cross piece as standard and would give more clearance generally. Your's do look very tight - so notching them is the only option.

With a standard arm, this axle probably gives plenty of clearance. An up-rated arm, being made from heavier wall tube either needs some notching or is made from the start with an offset end to increase the clearance. The QT design loks like an offset would be difficult to build in.

Si

[SteveG]

Better? Matter of opinion. Both jims and si's are excellent products but cant see you can say they are better! I have Gigglepins, I love them and would take a lot of convincing to change to anything else.

I did add the winks to imply it was a 'tongue in cheek' comment, but I obviously hit a sensitive point.

As for the arms, I can say that the design of the chassis side joint is much better on an X-arm. The Johnny Joint is a good enhancement to the rose joint providing extra movement, some bushing and ability to grease them. The X-Arm joint enhances on this design even further providing even more movement in all planes and extra bushing.

steve, have you had to clearance your brackets?

Adrian

Hi Adrian, no not yet. However, the X-arms have an off-set bush mounting so this would help.

Cheers

Steve

[Steve 90]

even more movement in all planes and extra bushing.

Steve

Yes, The X joint does have more movement but its not needed. The jonny joint has more than enough. I run gwyn lewis mounts and 11"OME shocks (which is more than enough movement for any challenge motor) with the gigglepin arms. I can articulate the axle to max on one shock, touch the bump stop on the other side and there is still quite a bit of movement left in reserve in the jonny joints so to have any more is a little pointless IMHO. The limiting factor is the A frame ball joint which Simon can sort you out for but a bit of alteration of mounting angle is a good thing there.

BTW, No sensitive point. Just I beleive they are both excellent products and both deserve a fair shout!

[pongo]

Regarding the Gigglepin arms versus others, when making up your mind, don't forget these other points;

Gigglepin arms are longer, so for the same axle droop, the arm has to rotate through a smaller angle, so less movement required on the joint.

The mount for Gigglepin arms gets rid of the downward-projecting elephant ear mount, so the bottom of the chassis is smooth, allowing it to slide over things where others will catch- think of dragging your vehicle over rocks for instance, nothing to catch so over you go. We also found this works very well in sand, not once getting stuck on dunes. And as for a bog, anything to reduce drag will help enormously.

Perhaps most importantly, the longer arm translates into much better drive; when the axle is at max droop, with standard length arms, a large component of the force is trying to push the car upwards - you will all have witnessed cars bouncing when trying difficult climbs - the longer arms mean the majority of the force is forward, not upward, so you make the climb instead of just bouncing. Switch to "smug mode" as you drive past the competition!

Finally, by christ they're strong.

[simonr]

Gigglepin arms are longer, so for the same axle droop, the arm has to rotate through a smaller angle, so less movement required on the joint.

That is true. However it is only true for droop. The Johnny joints have a max offset (rotation of the arm) if 15 degrees (+/- 7.5 degrees) compared to +/-17 deg for the average A frame ball joint.

If the axle articulates 17 degrees, the radius arms must rotate on their axis 17 degrees also. The additional 9.5 degrees is supplied by the screw thread that attaches the johnny joint to the arm. So, unless you are using the screw thread as part of the joint, you are loosing 55% of your available articulation. I don't really have a problem with this - but it's not a 'proper' thing to do. As steve says though - you probably don't need more articulation than these arms give you.

The mount for Gigglepin arms gets rid of the downward-projecting elephant ear mount, so the bottom of the chassis is smooth, allowing it to slide over things where others will catch- think of dragging your vehicle over rocks for instance, nothing to catch so over you go. We also found this works very well in sand, not once getting stuck on dunes. And as for a bog, anything to reduce drag will help enormously.

This is definitely one of the best features of the arms - and I do think it's a great way to go. Not everyone wants to cut off their radius arm hangers however - so there is still a place for alternatves.

Perhaps most importantly, the longer arm translates into much better drive; when the axle is at max droop, with standard length arms, a large component of the force is trying to push the car upwards - you will all have witnessed cars bouncing when trying difficult climbs - the longer arms mean the majority of the force is forward, not upward, so you make the climb instead of just bouncing. Switch to "smug mode" as you drive past the competition!

I have a couple of issues with this statement. Let's look at the maths / physics of it:

"with standard length arms, a large component of the force is trying to push the car upwards"

Standard arms are 715mm in length and the max droop is about 21 degrees. This means that there is 37.5% of the force pushing the vehicle forward is trying to lift the back end.

Gigglepins arms are 300mm longer which means that 31.7% of the force is trying to lift the vehicle - less than 5% difference.

I agree that 5% is significant - but in both cases, not just Gigglepin:

"the majority of the force is forward, not upward"

"you will all have witnessed cars bouncing when trying difficult climbs"

Yes - that's right. But the length of the arms and the torque reaction force is much less significant than the springs and shocks. A more common reason for this is too soft springs. As above (the ratio maths is the same) the difference in effect is less than 5%.

These things do make a difference - possibly a bigger difference than out and out articulation, but 5% is the best I can make the maths come up with - and that's not as huge a difference as your statement makes it sound.

I'm sure I'm going to get a reply along the lines of Jim's original brush off when I challenged the benefit of lengthened arms in terms of the locus of the nose of the diff without also lengthening the A frame:

"I win stuff so they must be good - end of story"

While it's true that a lot of the current winning teams are running Gigglepin arms, were they not winning before they fitted them too?

OK, I'm biased, however, I have never made any claims about X-Arms, and nor have QT about theirs, other than quoting the spec. It does annoy me when emotive claims are made about products where the numbers just do not back them up.

P.S. I heard that QT's arms can cure Baldness, acne and funny walks - so I'm afraid they are the best in my book!

Si

[Steve 90]

It does annoy me when emotive claims are made about products where the numbers just do not back them up.

Maybe so. But it also annoys me when people do things by numbers because very often in the world of all things off road (and many other areas for that matter) you can not reproduce all the many many variables in a mathematical/scientific calculation. I spent 16 years racing MX, involved with various race teams, spent a lot of time with suspension specialist and also spent quite some time building rally cars. Time and time again it was proved that what works best "on paper" just doesn't always cut it and every time the best results were got from what feels right.

I ignore the numbers and the claims and I speak as I find. If it feels good to drive then I do it. If it feels rubbish then it gets thrown away, as simple as that.

Im sorry if this sound like the reply you were sure you were going to get but maybe there is a reason for that. They do work even if the numbers don't back them up.

Sorry Si, No offense intended, As I said, I just speak as I find.

Steve.

[simonr]

Steve, I'm sure your right. I'll bet that nobody pays any attention to physics or maths in Formula racing, Rallying and the millions they spend on it is to give the nerds something to do.

We all know that painting a red stripe on the side of your truck makes it go faster too - I'll bet the maths doesn't back that up either.

Si

[Steve 90]

Steve, I'm sure your right. I'll bet that nobody pays any attention to physics or maths in Formula racing, Rallying and the millions they spend on it is to give the nerds something to do.

We all know that painting a red stripe on the side of your truck makes it go faster too - I'll bet the maths doesn't back that up either.

Si

Ok maybe I was going a little far saying to ignore physics and maths as a majority of the time they are very important in the design. But you know what im saying Simon. There are some situations, Off road Suspension particularly where an accurate recreation of the many variables is not possible and maybe the numbers are not necessarily a great representation of what may work and what may not. Sometimes you just need to go with what works through testing.

Steve.

[pongo]

That is true. However it is only true for droop. The Johnny joints have a max offset (rotation of the arm) if 15 degrees (+/- 7.5 degrees) compared to +/-17 deg for the average A frame ball joint.

If the axle articulates 17 degrees, the radius arms must rotate on their axis 17 degrees also. The additional 9.5 degrees is supplied by the screw thread that attaches the johnny joint to the arm. So, unless you are using the screw thread as part of the joint, you are loosing 55% of your available articulation. I don't really have a problem with this - but it's not a 'proper' thing to do. As steve says though - you probably don't need more articulation than these arms give you.

Not so. The pivot point of the radius arm is the chassis mount, ergo 715 mm. If the offside wheel is on the ground and the nearside has to drop, the pivot point is the length of the axle (1275mm or so?), hence the lateral rotational angle required is less then the longitudinal.

Also, for the same suspension travel, up or down, the Gigglepin arm goes through a much smaller angle, so the joint does not have to allow so much movement in either plane.

This is definitely one of the best features of the arms - and I do think it's a great way to go. Not everyone wants to cut off their radius arm hangers however - so there is still a place for alternatves.

I have a couple of issues with this statement. Let's look at the maths / physics of it:

Standard arms are 715mm in length and the max droop is about 21 degrees. This means that there is 37.5% of the force pushing the vehicle forward is trying to lift the back end.

Gigglepins arms are 300mm longer which means that 31.7% of the force is trying to lift the vehicle - less than 5% difference.

I agree that 5% is significant - but in both cases, not just Gigglepin:

I have done some calculations (being a structural engineer of some years), and come up with the following; at 11 inch drop, a reasonable figure, std length length arms will give a forward component of force of 47%, and an upward component of 53%. At the same drop of 11 inches, with Gigglepin arms the forward component of the force will be 61.7%, and the vertical component 38.3%. So, the difference in both forward and vertical force is 14.7 %. This is a significant difference, but is not the whole story; once the car starts to bounce, the kinetic energy of the descending mass is trying to force the car back down the hill, so there is an additional component working against you, compromising the ability to drive up the hill. So, combine the benefit of more forward force with the abscence of rearward kinetic energy, and the overall difference in performance is highly evident. And of course this has been proven in competition.

Yes - that's right. But the length of the arms and the torque reaction force is much less significant than the springs and shocks. A more common reason for this is too soft springs. As above (the ratio maths is the same) the difference in effect is less than 5%.

More damping needed, spring rates less significant.

These things do make a difference - possibly a bigger difference than out and out articulation, but 5% is the best I can make the maths come up with - and that's not as huge a difference as your statement makes it sound.

I'm sure I'm going to get a reply along the lines of Jim's original brush off when I challenged the benefit of lengthened arms in terms of the locus of the nose of the diff without also lengthening the A frame:

"I win stuff so they must be good - end of story"

I am not Jim, and this is not a "brush off". It is an accurately calculated response.

While it's true that a lot of the current winning teams are running Gigglepin arms, were they not winning before they fitted them too?

Maybe because they know a good thing when they see it....

OK, I'm biased, however, I have never made any claims about X-Arms, and nor have QT about theirs, other than quoting the spec. It does annoy me when emotive claims are made about products where the numbers just do not back them up.

P.S. I heard that QT's arms can cure Baldness, acne and funny walks - so I'm afraid they are the best in my book!

Si

In conclusion, while I applaud the design you have come up with, and x-arms may be the best bolt-on solution, they do not overcome the fundamental problems of geomoetry. I would also refer to the question of the material and shape of the arm. When dragging 2 tonnes of truck over rock, a large part of the weight will, at some time, rest on the arm. A point load of, lets say 1 tonne, at the mid-point of the arm, will not cause any damage at all to the Gigglepin arm. This is due to the material, its gauge, and the bracing. A standard-type arm, or a similar length after-market arm, would be unlikely to be able to take this point load, especially as it will be at a greater angle of attack to the rock face due to the steeper angle required as the wheel drops. The Gigglepin arm presents a smooth, flat, and very strong arm at a much shallower angle. In short, you won't break it! Remember too that the load imposed will be increased if you are trying to winch the poor old truck, so the arm will have to withstand the static weight as well as the winch load. We have all seen bent arms as a consequence of this.

I do hope this doesn't degenerate into a tit-for-tat argument, that is not my intention. I simply wanted to address some of the issues raised in a "calculated" way.

[bishbosh]

I am going to put my flack jacket, tin hat and stand near the door before I say this one.....

...... of course, fitting Gigglepin arms may raise the issue of SVA..........

BTW, I have neither Si's nor Jim's arms fitted, so not trying to queer the pitch. Both look like excellent products, one is bolt on, one isn't. One is longer, one isn't. Horses for courses.

[filthy boy]

"Standard arms are 715mm in length and the max droop is about 21 degrees. This means that there is 37.5% of the force pushing the vehicle forward is trying to lift the back end.

Gigglepins arms are 300mm longer which means that 31.7% of the force is trying to lift the vehicle - less than 5% difference.

I agree that 5% is significant - but in both cases, not just Gigglepin"

Have to ask how you worked this out? Is this based on a proper analysis of the roll centres etc and the anti-squat characteristics of the rear end? This is why vehicles bunny hop on climbs.

If not then it's a load of numbers and probably less valid than real world experience. What does a standard length arm (with or without fancy joints) do to the anti-squat and rear end dynamics with a 2" lift? I should think this effect is way more important than pinion rotation in producing a capable vehicle.

And why is everybody obsessed with the freedom of movement in joints? Suspension needs some roll resistance to make a vehicle handle decently (at anything over crawling speeds, oh but that's when anti-squat might become pretty important ). A rose jointed / other free joint suspension MUST have roll resistance added back in the forms of sway bars or something clever.

And as a parting shot, the design and material of the standard LR radius arm is pretty near perfect material engineering.

Right, that's my fuel poured on the fire. Bye

Tim

[ciderman]

Ok sort of back on topic , My front QT arms have badly bent , along with a front qt diff gaurd , So im going back to standard arms until one of you clever chaps can come up with a soloution and make some FRONT arms that work and dont bend like the chocolate QT ones .

[filthy boy]

Ok sort of back on topic , My front QT arms have badly bent , along with a front qt diff gaurd , So im going back to standard arms until one of you clever chaps can come up with a soloution and make some FRONT arms that work and dont bend like the chocolate QT ones .

No need to wait, Land Rover have already developed great radius arms. :lol: :lol: :lol: :lol:

[will_warne]

No need to wait, Land Rover have already developed great radius arms. :lol: :lol: :lol: :lol:

What he said and clock the swivels. Problem solved! B)

[ciderman]

No need to wait, Land Rover have already developed great radius arms. :lol: :lol: :lol: :lol:

Thats what I thought , So im going back to them , Ive seen just about every type of aftermarket Front arms bend (scorpion ones being the worst)

But I have rarely seen a standard arm bend .

[ciderman]

What he said and clock the swivels. Problem solved! B)

Not too bothered about clocking the swivels Will , It rarely sees Tarmac so bump steer isnt to much to worry about .

[landrovermanuk]

I was going to change my radius arms but after reading this would I be better going for castor correcting bushes as my 90 has a 2 inch lift?

Sorry what does clock the swivles mean???