Yes, do a search. It's been covered loads. MK use them as do many others. including myself !

Paul

I wonder if you might like to consider joining in the general fun and banter, rather than just posting one liners, as if this site is just an auto answer knowledge base.

said in the nicest possible way.

atb

steve

Here's mine on the MK
Rescued attachment view over front hub.jpg

couldn't help but notice on your setup; assuming the flexi's are to the rear; the mushroom thingy which the top balljoint fix's into is in the opposite way to ours... is there a handling reason per chance?

Just a general question as we were advised otherwise

Think you'll find that Bob's is the way your supposed to fit it. I made mine, without seeing or knowing about anyone elses, and thats the way i fitted mine. Thats the MK way, and everyone elses way. Cant see how it would work the other way round. Just aslong as your talking about the mushroom insert where the sierra shock should be

Image deleted by owner

This is a picture of MK's Red Rocket... with suspension setup. The mushroom thing double touching circle thing is to the front... am I missing something?

If you don't see the image look at pic p90301651 in our archive.

[Edited on 1-1-04 by Hellfire]

Errrrr so is bob's ??!??!?!?! There's no difference


Image deleted by owner

[Edited on 1/1/04 by Ben_Copeland]

must be the angle I'm looking at it then... we have ours same as MK's. Just a clarification point

Yeh, its the angle of bob's picture, if you glance at it, it makes it look like the balljoint is offset the other way but it's not

quote:

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Originally posted by Hellfire
couldn't help but notice on your setup; assuming the flexi's are to the rear; the mushroom thingy which the top balljoint fix's into is in the opposite way to ours... is there a handling reason per chance?

Just a general question as we were advised otherwise

---

I think (having not seen the part) that he means the hole isnt in the centre of the adapter - excentric - and you can move the dapter around to give camber change and castor change.

I made my own with the hole in the centre and it seems to work.

atb

steve

Yes your right steve they are off centre,and i think the later adapters are even more excentric by at least another 5mm off centre.

Upon closer scutiny of the picture that Bob posted - it's his foot that distracted me

It's no doubt it's my interpretation of the picture and the angle of Bob's photo which was obviously so he didn't loose his balance.... errr maybe....

I apologise for my poor parallax error and defer to Bob's, Ben's and everyone else's superior knowledge. I'm not really a senior builder just a happy poster!!!

HaPpY NeW YeAr To YoU AlL!!!

Where's me bottle gone???

Thinking about this logically, it doesn't matter how you put the mushroom in, the castor angle is determined by the centre of the balls of the ball joints top and bottom. The mushroom insert can be in any orientation and it doesn't effect the ball joints position and therefore cannot effect castor, or indeed the steering feel.

Kind regards,
Darren

indeed darren, i thought that myself a while ago. However, on a poorly designed car like mine, it allowed a bit more play in the camber settings, as my top bone was a fraction too short so i spun the mushroom round to make the wheel more upright.

dozracing:

quote:

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Thinking about this logically, it doesn't matter how you put the mushroom in, the castor angle is determined by the centre of the balls of the ball joints top and bottom. The mushroom insert can be in any orientation and it doesn't effect the ball joints position and therefore cannot effect castor, or indeed the steering feel.

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On first reading Darren's response I was inclined, (no pun intended) to disagree. However after further consideration, prompted by Rorty,s reply I'm now not so sure.

Would it be correct to say that adjusting the eccentric will adjust camber but not castor?

Mick

With an offset hole in the mushroom, you will be able to adjust camber and castor.

HNY

ATB

Simon

My opinion would be that it would make substancial changes to camber, and possibly small changes to castor - it quite possibly alters the distance between the ball joints fractionally, hence changing the castor angle, but to what degree this would occur, I wouldn't like to comment.

Kingr

Kingr

Isn't the position of the balljoints fixed by the wishbones ? (castor wise)

Thought provoking

Mick

Set the adaptor with balljoint hole in its furthest forward position, and set the camber to vertical (by using the thread on the balljoint).

Now rotate adaptor 90 deg anticlockwise (work with offside only cos it's reversed on t'other), camber becomes positive, and castor decreases. Rotate another 90 degrees and camber resumes neutrality and caster decreases further. Turn left again and you'll have neg camber and increased castor.

The wishbone doesn't move, only the upright's position changes.

Clear

Trust me, I've got them. If hole is 1/2" of centre, then you'll have an inch to play with.

ATB

Simon

My opnion....

Castor angle will not change (as Darren says it is determined by BJ positions), but trail (distance between line through BJs and tyre centre line point where the intersect the road) will vary because the actual wheel itself will be moved forwards or backwards and consquently affect self-centreing....after all the purpose of castor is to create trail.

So althogh the actual angle of castor is unchanged it will certainly show the effects of being changed.

Camber is changed of course, on question there.

Again all IMO.

Just to add another spanner to the works, you will also be adjusting the King Pin Inclination by effectively changing the geometry of the upright but only if you correct the camber change.

quote:

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Originally posted by Mix
Kingr

Isn't the position of the balljoints fixed by the wishbones ? (castor wise)

Thought provoking

Mick

---

quote:

---

Originally posted by dozracing
Thinking about this logically, it doesn't matter how you put the mushroom in, the castor angle is determined by the centre of the balls of the ball joints top and bottom. The mushroom insert can be in any orientation and it doesn't effect the ball joints position and therefore cannot effect castor, or indeed the steering feel.

Kind regards,
Darren

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Kingr

I agree, but I think the results would be insignificant.

JC

You have two ball joints fixed longitudinally and laterally in space, (by the wishbones). (This is a loose description but good for this case).

Turn the eccentric any way you will, all that will happen is the inclination of the upright will change.

Good thread though

Mick

Mick,

Yup, agreed, they'll be pretty marginal, it depends on the initial castor angle and the distance between the ball joints. I think the crux of the matter is that you couldn't call it adjustability, more just a (very slight) side effect.

Kingr

surely, as you rotate the excentric hole thro 4 steps of 90 degrees, you will get 2 positions where camber is affected and 2 where castor is affected.

suspension issues are always ba$#ards are they not

atb

steve

I'll state my opinion again...which I strongly believe to be correct.....

Castor ANGLE is not changed, but the "castor" effect is changed due to the fore and aft movement of the wheel relative to the castor angle line's intersection with the ground. (trail)

Also, I would disagree with Mark? (I think) in that KPI is not changed as the BJ centres don't move.... however camber is changed of course.

Bottom line..... the BJ centres don't move.....KPI and castor are measured using BJ centres so therefore they do not move either.

I do agree though...good thread..

Now that we seem to be seeing light at the end of the tunnel on this one has anybody considered the effect that rotating the eccentric will have on bump steer ??

Mick

Been thinking about this again this morning, i haven't got a Sierra upright to look at but, if the castor line thru the ball centres is off set from the wheel centre then it will make a small difference to trail.

On a cortina upright wherre there is no offset it would make no difference.

On our kit we use an concentric mushroom, and put the desired camber in the top wishbone.

Kind regards,

Darren

Alan, what I meant about KPI was if you change the offset of the top balljoint the camber will change, but to reset your camber to its original setting, you would have to alter the balljoint positionrelative to the car and therefore altering the KPI

alan has it COMPLETELY right IMHO.

i was gonna post in my first post that you would have to go back to basics and work out why castor angle affects self centering.

the gist of it, in my opioion, is that trail causes selfcentering, and one way of making trail is to lean the hubs back. other ways are possible, namely by moving the center of the hubs rotation back so it is behind the axis of steer. this is what happens when the mushroom is rotated.

so technically, if you define castor angle as the angle between the two balljoint and vertical, the mushroom does not affect this, even though it will increase trail.

Mark....I see what you mean...readjusting the top BJ to correct the camber change caused by the mushroom will change KPI..agreed.

Joel..Good at least two of us agree..

Essentially i think we have found all figured the correct reasoning.

I think though that the eccentric adjuster is a poor solution, better to put the desired castor/camber/KPI in your basic layout than in an eccentric bush. If you have the eccentric bush loaded laterally the force acting on it will want to twist the bush and so alter your geometry.

Its also a lot more expensive to make them eccentric as you then have to mill them or use more sophisticated off centre tooling in your lathe.

Kind regards,

Darren