C7-420R Upper Wishbones - are they handed?

[Purplemeanie]

Hi All,

first post, so be gentle with me! :-)

I’m just starting a 420R build and have got to my second day of build: front suspension.

I foolishly took the wishbones out of their wrappers without paying attention to handedness.

The lower wishbones are easy to identify... circlips face downwards.

However, the manual says that the upper wishbones are handed but I can’t see any discerning way to tell the difference. Is there something to the geometry of the mounting points? I offered both uppers to the chassis on both sides but they both look feasible in both locations.

... any suggestions, what am I missing?

thanks in advance, John

[Jonathan Kay]

Welcome. Where are you?

The 2014 Assembly Guide says:

5.3) Upper wishbones

The upper wishbones are handed and are assembled with the longer leg facing the front of the car. 

But I don't know if anything has changed or if 420s are different. What does your corresponding section say?

Jonathan

[ScottR400D]

Unless they've changed since I built my R400 in 2015 they're not actually handed. 

In my kit I had two that were both labelled LH. I mailed Derek forthwith and asked for a RH one. 

Then looking at them, I realised that if you rotate the ball joint 180, the LH magically becomes a RH!!

I mailed Derek to forget my first mail and asked him to confirm what I was doing. A one word reply: Yes!

felt a bit foolish really but still don't know why they bag them up L and R. 

[Purplemeanie]

Thanks Jonathan, that’s right the long leg faces forward... but... you can make the long leg forward with both of the Wishbones, you just have to flip them front to back. Still not sure which is the OS vs NS.

john

[Purplemeanie]

Thanks Scott... that’s sort of where I got to. The manual says they are handed but for all I can see you can interchange. Glad to hear Derek confirmed this with you.

[Jonathan Kay]

Fascinating. Are these the right ones?

They have different part numbers!

Then looking at them, I realised that if you rotate the ball joint 180, the LH magically becomes a RH!!

Is the receiver for the antiroll bar in the same plane as the arms?

Jonathan

[Purplemeanie]

Hi Jonathan,

As far as I can make out the upper Wishbones are identical OS vs NS. The ball joint orientation doesn’t seem to come into the equation.

At the moment ScottR440D’s statement is my default position unless anyone can tell us differently.

You asked where I am... Bristol. 

John

[ScottR400D]

Yes JK, the ARB sockets are on the centreline of the tube. 

I'm not sure why they list them as L and R; as I've said I was sent two bagged and labelled LH but simply adjusted the joint, all under DH's guidance. 

[John Vine]

If you rotate the ball-joints, you will alter the camber, albeit only slightly.  This may not be significant, however.

JV

[ScottR400D]

That could be the case but would have to assume that the threads, in both the wishbone and on the ball joint, picked up at exactly the same point, which is unlikely. I wouldn't think it's significant. 

The camber on my car is equal both sides as near as can be measured with a camber gauge, and both my wishbones were supposedly the same hand. 

[Jim 123]

I recall that the Build Manual says to move the ball joint settings "x" rotations of of their thread from the fully home position to get a preliminary camber set before you connect the uprights.  Once the car is on wheels it's worth checking the camber again as the wishbone manufacturing tolerances are not great, and you may find the camber is not the same on both wheels.

[John Vine]

The latest (Feb 2015c?) Assembly Guide says:

Check that there is an equal amount of exposed threads between the locknut and ball joint, this should be adjusted to eight threads for normal road use

I suppose you could argue that these wishbones are handed to the extent that CC include two ready-assembled items in the kit (with different P/Ns), and wish to minimize confusion during the build.

JV

[Jonathan Kay]

...the ARB sockets are on the centreline of the tube. 

Thanks

Jonathan

[Purplemeanie]

Thanks for all the feedback. Wishbones now installed. Will do final checks when the car is on its own wheels.