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unequal length wishbone mounts
Delinquent - 12/9/08 at 06:25 PM

I've "borrowed" a bit of design inspiration from another vehicle for a possible project, but looking at it in more depth I noticed that the front wishbones have the rearward mount points considerably nearer the wheels than the front mount points. Or to clarify, the mounts are not parallel to the centre line of the vehicle, but skewed outwards considerably from the centreline.

Now struggling to get my head around what possible implications that would have on the suspension travel - jury rigging a matchstick model up just confuses me further so thought I'd take the simple approach and ask you lot

[Edited on 12/9/08 by Delinquent]

blakep82 - 12/9/08 at 06:37 PM

its how my ex-race chassis is... if its good enough for a professionally designed and built chassis....

built by SHP btw.

dunk3 - 12/9/08 at 06:39 PM

hi everybody . what size fuel line do i use and does it have to be rubber or copper . i will be fitting it to a mk indy zetec .which is the best route to fit it and what is the correct gap for the p clips you use to fasten it with. thanks.

dunk3 - 12/9/08 at 06:51 PM

sorry put the question in the wrong box

mark chandler - 12/9/08 at 08:03 PM

makes no difference as long as you keep parallel with the centreline of the chassis. Rescued attachment f2_1035b.jpg
Rescued attachment f2_1035b.jpg

nick205 - 12/9/08 at 08:09 PM

quote:
Originally posted by mark chandler
makes no difference as long as you keep parallel with the centreline of the chassis.


I think he's seen is a design where the inner wishbone pivot points are NOT parallel to the chasis centreline

I have seen this sort of layout too, but couldn't tell you what the effect might be on castor, camber, toe etc through the suspension travel.

Slightly different, but many rear suspenion set-ups with trailing arms (e.g. Sierra) do not have the inner pivot points parrallel or perpendicular to the chasis centreline.

Delinquent - 12/9/08 at 08:25 PM

quote:
Originally posted by nick205

I think he's seen is a design where the inner wishbone pivot points are NOT parallel to the chasis centreline



exactly

Looking at other oddities out there I'm seeing more and more of it - interesting if not slightly confusing!

MikeR - 12/9/08 at 11:19 PM

I'm curious what happens if you have the rear (furthest from the front of the car) a smidgen nearer the centre line. I'm never 100% convinced mine aren't - despite using a wooden batton bolted to the front and back and it fitting perfectly (plus using a jig to weld them.

So i suppose i'm interested in the opposite answer (just in case - paranoia, don't you love it?)

blakep82 - 12/9/08 at 11:23 PM

well, with mine, when the wheel is pushed up, the bottom ball joint moves slightly back (reducing the castor angle)

i'm sure there is some kind of benefit in it (combined with body roll for example?) but i can't work out what it is...

with the suspension travel what it is, i don't think it makes enough of a difference to the castor anle to be a problem though

t.j. - 13/9/08 at 05:46 AM

I don't want any "unidentified" movement in my car.

The Sierra is "wobbeling" around in corners and has big rubber bushes every where to compensate the travel/steering.

I think you could use this, but, have a look under a Audi A4 which also has a lot off 'not logic' wishbones placement.
Without good calculation and 3D i won't try it and keep it in the old fashion-way

Delinquent - 13/9/08 at 09:33 PM

quote:
Originally posted by t.j.have a look under a Audi A4 which also has a lot off 'not logic' wishbones placement.
Without good calculation and 3D i won't try it and keep it in the old fashion-way


Funny you should say that, I've got an A4 and you are right, it is all bit odd!

I've drawn it up fully in CAD using equal length inboard-mounts-not-parallel-to-chassis wishbones, in that instance the difference is a shortening of wheelbase in bump OR drop - by a not inconsiderable margin. Will set forth again tomorrow but use unequal length wishbones of known quantity (book locost) and see what happens then