Rose-jointed suspension

[Cedric]

Many modern race cars seem to have this, but I never fully understood what it actually is. Could anyone explain me what it looks like and how it works. And when was it invented by the way?

[Matra et Alpine]

rose jointed existed before 'normal' joints

The most common rose joint you will see on every car is a track control rod end.
It's a spherical ball in a joint which allows angular movement whilst retaining position.
It sits on threaded section which allows variation in the dimension of the connecting point at the joint.

So a fully rose jointed suspension arm woudl have a variable rose joint at EVERY connection point. Normal suspension arm would have bushes at the chassis ends and a ball joint at the wheel end. THe fist joint normall oncverted to a rose is the ball joint as now the driver can vary the camber on the wheel very easily by adjusting the length on the rose joint to move the ball in or out relative to 'normal'. NEXT a serious racer would have rose jointed inner arm bushes and then able to adjust caster and dynamic angle changes during suspensino compression and rebound.

As rose joints are metal to metal surfaces they wear more than metalistic and polyurethane bushes AND they offer no vibration and impact absorption. So a full rose jointed car is a nightmare on rought roads

[Cedric]

If they are metal to metal surfaces, how are they lubricated, and are rose joints a synonym for uniballs? Has anyone got a picture of rose joints?
If you say they existed before normal joints, why did F1 cars of the 50s have few possibilities in the way of altering suspension settings?

[Matra et Alpine]

If they are metal to metal surfaces, how are they lubricated,

They used to be greased with grease nipples.
If you ever get the chance to look over a classic competition car you will find LOTS of grease nipples
Modern materials allow them to not need geasing BUT won't last for a season adn don't survive the knocks as well.

and are rose joints a synonym for uniballs? Has anyone got a picture of rose joints?

Never heard of "uniball" Common language seperation again
Ball-joint is usually same construction as the cheapest rose-joints.
But as described, it's the way a joint fits to the fixed parts fo the suspension arms that gives the adjustability.

If you say they existed before normal joints, why did F1 cars of the 50s have few possibilities in the way of altering suspension settings?

Who told you THAT ?
True for live rear axle cars - there's not much option for changing angles for a fixed rear tube
Also true for leaf springs - 'normal' not the transverse.
But where these didn't exist, ball joints were prevalent ( actuallying sleeve joints were more common, so it's not as clear-cut as I'd made out )
There are lots of adjustability in 50s competition suspension.
BUT with the difficulty of producing rose-joints that coudl cope with the wear it WAS more common to use sleeves and offset shims to do adjustments.

[Cedric]

I have checked, and uniball is the same as ball joint, I guess it's French, and is derived from unir (to unify) ball -this must be the etymo(logical) explanation.

I read in several books that suspension setting changes were minimal back then. Many 50s F1 cars used friction dampers and those with a transverse leaf spring could have their roll stifness altered by means of moving rollers in between which the leaf spring lied.

[Cedric]

wouldn't it be easier and cheaper to regularly grease the things instead of replacing them every season?

And are they synonymous to ball-joints or is there a difference in construction?

[Matra et Alpine]

wouldn't it be easier and cheaper to regularly grease the things instead of replacing them every season?

Not with modern materials.
Grease requires a gap between the ball and the cage. THAT means movement.
Modern rose joints can have ZERO movement if you pay enough for them and don't mind their shorter life.
Lifetime's not usually a major problem for a modern race team. After all teh driver will liekly have kerbed it enough for them to want to change them as a matter of course each event !!!!

And are they synonymous to ball-joints or is there a difference in construction?

bascially same thing, though ball joints typically have the ball held in a sealed cup whereas rose joints are usually open and a bolt or bar goes THROUGH the centre. See earlier pic.

[Cedric]

So, all this means that owning a British road-going sports car with rose-jointed suspension will cause headaches every time you have to replace and retune the suspension settings.

[Matra et Alpine]

So, all this means that owning a British road-going sports car with rose-jointed suspension will cause headaches every time you have to replace and retune the suspension settings.

no, depends on the rose joint !!

But expecting a rose jointed car to go 100,000 mniles without replacing components would be stupid

PS: It's not just British sportscars that rose-joint. It's ANY SERIOUS perfromacne car that wants to allow the driver to adjust the car to track adn road adn rally conditions.

AND they're not hard at all to replace - a LOT easier than all the metalastic bushes ordinary cars have

You're leaps of imagination need a little restraint !!!!

[RacingManiac]

Rod ends.....that's what we call those here....in N. America....

[Matra et Alpine]

Rod ends.....that's what we call those here....in N. America....

same here when they are track control arms.

What about when they are on the suspension arms adnd pivots ? Are they all called rod ends then ???

[Cedric]

so, would you advise rose joints on a proper sports car?

[Matra et Alpine]

so, would you advise rose joints on a proper sports car?

Only if the driver was capable of setting it up or there was a VERY good mechanic around.

Generally though I would always recommend it for serious driving as even manufacturing tolerances can introduce variation in suspension alignment AND it makes it MUCH easier to tweak camber and suspension arm length for improved cornering.

[Cedric]

but that requires a decent laser-operated alignment device, or would some testing and a tyre temp gauge do the job as well?

[RacingManiac]

On our FSAE/FStudent car we run pressed in spherical bearing, so we don't use rod ends.....so does F-BMW car that I've worked on....

They are good for getting rid of compliance in the system, unless you want the compliance like in road going cars....same with bushings in the shock mounts/tie rods and all the other pivot points in the car. And this is also the reason why by replacing the rubber bushing with the stiffer polyeurathane ones you get bump up a class in the SCCA/Autocross events here....less compliance, more response, more wear and tear on every thing...

And yes, you need to replace rod ends every once in a while when they get sloppy...