Superior Engineering Superflex arms for Rovers.

For the suspension experts out there I have a question ( probably of little relevance)
When looking at the standard height rover RA front end side on draw a line through the middle of the axle end RA bushes (middle of bolt holes or heads on one side)
When you lift this front end using springs only, that angle the bushes are on would change
The change would be the same degree as caster change
I know the different feel 3 degree (out) caster has[bighmmm]

What handling characteristics are changed with this differing bush angle??
(Other than caster which could be isolated and changed by rotating swivels)

Dc

Im no expert. Those bushes are still going to be in the same relation to the housing as stock, as the whole lot has rotated. The panhard at axle end will have a little more bind in it over stock, due to the housing rotating. One thing that does get worse is how the front handles bumps at any speed other than sub 2km/h. As the arms are now not level(ish) when they travel up (compression) they also are traveling forward due to the arc scribed by the arms. But when you are moving forward the axle wants to move upward and rearward due to forces.....this is where things get harsh, they are fighting each other. This is not due to the bush angle though. Of coarse you also have more bump steer and roll steer with lift, but again not due to bush angle but link geometry.

Uninformed has said it, I just want to reinforce it.

Unrelated to the question Uninformed answered, raising suspension has upsides and downsides. The upsides are all found off road, but not in all situations.

This is why I am a convert to air springs for what I require now, to enjoy variable ride height. Stock or even a little less on road. Low, even to the bump stops in bad off-camber off road, a comfortable height that can soak up bumps off road or on badly rutted roads, or temporary changes to increase approach, departure or break-over angles on particular obstacles. There are other reasons, such as retaining the ride height when the payload is changed, and active height control during cornering, or braking.

I hope these arms will improve how the front suspension works off road, and improve the balance between front and rear articulation.

Dave, If you asking if changing the bush relation to the housing, ie not the seperation, but their placement, say from stock to say more vertical placement, then I can not answer if that will change how they deal with the forces seen during accleration/brakeing etc. I would say your antidive would be the same for a set height, given the convergence point of the RA is still the same. I think the axle roll axis angle would remain the same as the 2 bushes seem to disect the centre line of the axle housing, and if you rotated the bushes aroung this wouldnt change.

not 100% sure :confused:

Quote:

---

Originally Posted by Bush65

IMHO, correcting castor by rotating the diff, via RA or bushes, is the wrong approach. It increase the drive shaft angle, from bad (stock) to even worse.

There is benefit in cranking the RA for raised suspension, but it should be done to correct the angle at the chassis bush, and to correct the pinion angle, ideally for a double cardan drive shaft.

Castor is best corrected with the swivels.

---

I really don not understand this statement.

When you add lift, the diff rotates in a downwards arc, yes the panhard gets induced bind and the pinion angle rotates. And I realise we're mostly talking about pin end arms like RRC/D1 (I'm a D2 so don't have chassis end bush issues). If the RA's are corrected correctly then the diff is relocated back into it's original location. Panhard and pinion positions are stock, castor angles are returned.

Yes In a D1/RRC the lift induces chassis end bush issues but these are corrected as said with cranked arms that also need castor correction at the diff end. I only know of one mob that did bent arms for castor correction and it's no longer available. Rotating the swivels does not return the housing to it's original position, does not alleviate panhard binding and does not reduce the chassis bush issues.

Quote:

---

Originally Posted by clubagreenie

I really don not understand this statement.

When you add lift, the diff rotates in a downwards arc, yes the panhard gets induced bind and the pinion angle rotates. And I realise we're mostly talking about pin end arms like RRC/D1 (I'm a D2 so don't have chassis end bush issues). If the RA's are corrected correctly then the diff is relocated back into it's original location. Panhard and pinion positions are stock, castor angles are returned.

Yes In a D1/RRC the lift induces chassis end bush issues but these are corrected as said with cranked arms that also need castor correction at the diff end. I only know of one mob that did bent arms for castor correction and it's no longer available. Rotating the swivels does not return the housing to it's original position, does not alleviate panhard binding and does not reduce the chassis bush issues.

---

Rotating the swivels maintains the correct geometry of the pinion to the t/case output flange, bending arms doesn't.

If you bend the radius arm to correct for castor you start to point the pinion flange down, and for correct alignment a DC shaft needs the pinion to point directly at the t/case flange.

To correct the pin angle (depending on lift) you'll need a bend in the opposite direction, a big S.

Quote:

---

Originally Posted by clubagreenie

I really don not understand this statement.

When you add lift, the diff rotates in a downwards arc, yes the panhard gets induced bind and the pinion angle rotates. And I realise we're mostly talking about pin end arms like RRC/D1 (I'm a D2 so don't have chassis end bush issues). If the RA's are corrected correctly then the diff is relocated back into it's original location. Panhard and pinion positions are stock, castor angles are returned.

Yes In a D1/RRC the lift induces chassis end bush issues but these are corrected as said with cranked arms that also need castor correction at the diff end. I only know of one mob that did bent arms for castor correction and it's no longer available. Rotating the swivels does not return the housing to it's original position, does not alleviate panhard binding and does not reduce the chassis bush issues.

---

Lets call the pinion angle at stock ride height "correct" for this example. Lets call castor at the swivel 3 degrees. The "correct" pinion angle at stock ride height, is in relation to the transfer case output flange. Note that as soon as you change the vertical difference between the diff pinion and the t/case output flange, for the same give horizontal length (lets ignore the small amount the diff swings front to back in its arc) ,i.e. lift, then the given pinion angle must change to be correct at the new ride height. So setting the castor corrected arms up so that at 3 inch lift you have 3 degrees castor at the swivel is probably not going to give you the correct pinion angle for that lift, but rather the "correct" pinion angle for stock height/no lift as the pinion and castor are in relation to each other set at factory.

If as the RA arc down from stock the pinion angle remains within a fair working range, then leaving it as is and rotating the swivles is better.

John's solution of cranking the arms is to set the ideal pinion angle for a given ride height and then rotating the swivel to set castor. A person may even want more than +3 degrees depending on lift and tyre size.....

The other thing to remember is that the stock front propshaft on older coil sprung LR, RRC and Disco 1 is out of phase due to the angles that the t/case out put flange and pinion are at stock... so there are other options with conventional propshafts and DC propshafts

Just for all whom may be interested, I have found that cranked arms seem to line up pretty darn good for a DC to be used in the front drive shaft.

As someone who has been using cranked arms for a long time, all I can say is I am very happy with them.

I have also found the pinion angle change makes little difference to real world results for my given application.

Also I replaced my holey bushes on Friday as they were extremely worn out.
As I was heading to The Springs 4x4 park over the weekend I chucked in some standard (none genuine) radius arm bushes just for this trip.
All I can say is the amount (or lack) of front flex was amazing. The front flexed about 4" all up, as opposed to what I would guesstimate to be 9" with the worn holey bushes.
This caused my rear end to work a lot harder. I would say that for the first time since driving my RRC that I may have finally used up all the travel from the rear shocks (13").

As my rear end is fairly loose (designed to work with the loose front end provided by the holey bushes) the results of a stiff front end were shocking.
My opnion is that if you have even just put longer shocks in the rear of your rover, then the front needs the holey bushes or the super flex arms for the vehicles to perform satisfactory.

I am certainly looking forward to reviewing the super flex arms, and getting rid of these standard bushes.

Cheers
Grimace

Quote:

---

Originally Posted by clubagreenie

I really don not understand this statement.

When you add lift, the diff rotates in a downwards arc, yes the panhard gets induced bind and the pinion angle rotates. And I realise we're mostly talking about pin end arms like RRC/D1 (I'm a D2 so don't have chassis end bush issues). If the RA's are corrected correctly then the diff is relocated back into it's original location. Panhard and pinion positions are stock, castor angles are returned.

Yes In a D1/RRC the lift induces chassis end bush issues but these are corrected as said with cranked arms that also need castor correction at the diff end. I only know of one mob that did bent arms for castor correction and it's no longer available. Rotating the swivels does not return the housing to it's original position, does not alleviate panhard binding and does not reduce the chassis bush issues.

---

You would be correct if at standard height the front output shaft of the transfer case, and the front diff pinion were parallel. Then for a suspension lift, correcting castor would also correct the pinion angle. Parallel is the convention way that universal joints are aligned for drive shafts.

However since Land Rover changed to coils, the front TC shaft and pinion are not parallel, and the universals are out of phase to reduce vibration. It stays reasonably correct when the suspension is lifted, but can never be perfect. When castor correction arms/bushes are fitted, the diff pinion is rotated down, the already too great operating angle of the universal at the TC end is made worse. The pitiful maximum operating angle of the ISO universals that Land Rover use can not accommodate much droop from the raised height, and even less droop is castor correction arms are used.

The best solution if you want to do longish trips with raised suspension is to use a double cardan front drive shaft. This changes the correct pinion angle again. I note grimace stated it is not too far off for a double cardan drive shaft, but again I suggest not the ideal pinion angle.

With a double cardan drive shaft, the diff pinion should be 0.5 to 1 degree off parallel with the drive shaft. Because of the poor maximum operating angle of the double cardan joints for Land Rover use, and the affect on droop that I mentioned above, it is better if the pinion is pointing 0.5 to 1 degree above parallel, rather than 0.5 to 1 degree below parallel.

The pic below shows the comparison of operating at universal bind condition of 3 drive shafts. The top is the standard wide angle universal used by Land Rover. The middle one is a disco II double cardan drive shaft. The lower is a stock Nissan single universal drive shaft.
https://www.aulro.com/afvb/images/im...14/01/1584.jpg

With Land Rovers, you can do a modest lift reasonably cheaply, but over that it becomes expensive to do properly.

It makes little sense to me to spend the $$$ required for springs, shocks and superflex RA's to not do the job properly and add a double cardan drive shaft. And to do this properly the diff pinion angle needs to be corrected for the double cardan drive shaft, and the only way to do this is with the radius arms. Then the castor needs to be corrected with the swivels. Do the job properly, and don't stuff it up with radius arms designed to correct castor.

A Land Rover is not the same as a Patrol or Landcruiser, and different rules apply for obtaining good results when the suspension lift is around three inches.

I have a custom DC drive shaft.

I drive my vehicle long distances.

At the moment my front cranked arms are slightly over corrected as the lift is not as much as the arms are designed for. Arms are for 4" lift and my front is about 2.5" assuming I am not a complete muppet and calculated approx.

So given the above, my pinion is actually below the optimal range of the DC shaft, by the exact amount of degrees I am not sure.

There is no vibration, no issue at all. Car actually drives very good with the new standard front bushes.
Longer trailing arms in the rear would be my next upgrade for on road drive-ability and to reduce some of the rear steer under articulation. I wouldn't be doing it in an effort to increase the travel from the rear it's more then enough (too much actually).

It works for me. Has for years.

As with the super flex arms, I will work out what suits my vehicle best. Trial it. If it works it will stay, if it doesn't it will change.

edit: Sorry this is just me adding more facts for people. This is not to be mis interpreted as a dig at bush65 or uninformed. Just read back over the last couple of post and thought it may look that way so just wanted to clarify that before someone takes it the wrong way.