Wheel/Suspension Setup

[derdle]

Tie rods like these are supposed to help reduce "bump steer"....

[ZeroK66]

What are they/where do you get them?

[derdle]

They are steering rod/tie rods for my RS4, haven't put them on yet though . They were recommended when I had the suspension lowered on the H&R coilovers. I bought them together with adjustable top links for the front and rear in order to get the suspension geometry sorted properly. Sadluy the company that supplied the lot (Custom Performance Products in USA) seem to have gone t*ts up....website is down and no reesponse to e-mails.

[kies4]

I local BTCC racing driver Rick Kerry (diesel 1 series bmw) offers a corner weighting service(motorsports industry and now private customers), the system wasn't running when i got my allignment and height done .
He has contacts in the racing industry to get suggested settings from and works from there. I was well chuffed with the setup he gave me, and I'll be going back to get the corner wieghting done before the next ring trip, seems odd to be able to move the wieght around adjusting the suspension settings but I've heard it can make a huge difference

[ZeroK66]

Kies, have you got a contact number/web address for him.

Anyone else know of another company that supplies the rods as mentioned by Derdle? Sounds ideal for running a car low, but keeping geometry the same...

[DavidT]

Thanks Matt, thanks David...

David, do you remember your suspension height? I seem to recall a million years ago seeing a post you made with height at the front and rear?

As I have the larger rear ARB would it not be wise to set this to the softer setting? This would probably = the stiff setting on the smaller H&R ARB.

I have had the car back about 2-3 weeks now and I find the bump steer is only particularly bad at low speeds. The car is really bumpy on rough bits of road - to the point where you end up causing the car to kangaroo because you cant keep your right foot still and end up tapping the throttle... very funny.

When I am next up to see Doug I shall deffo get a few things changed as suggested here. I will keep you posted.

I've found the details of this:

Measured from the highest point inside the wheelarch to the ground, the ideal settings are:

o/s/f 64.8 o/s/r 65.5

n/s/f 64.8 n/s/r 65.5

I think this info came from H&R.


Originally, I had mine at:

o/s/f 63.5 o/s/r 64.5

n/s/f 63.0 n/s/r 63.8

Car handled great at this, I did not have H&R uprated ARB's at the time, which was a factor I'm sure.


Now they are:

o/s/f 63.8 o/s/r 65.0

n/s/f 63.8 n/s/r 65.5

Which is about as high as you can get the H&R coilovers (min 30mm drop)

Bear in mind that they will always settle a bit differently.

Regarding the big rear ARB, yes it would still be an upgrade on the softer setting but you will have less understeer with it set stiffer. Try both. I've found the big rear on stiff to be too stiff on trackdays in the wet.

You can change the ARB settings easily of you can get under the car or have access to a ramp - paying the Kwik Fit guy a tenner works.

If you increase the ride height & set the front ARB to soft, you will notice a huge difference, so much so that you would not think its the same car.

[S4]

Measured from the highest point inside the wheel arch to the ground

is it easy to do that? would the top of the arch (outside) not be more easy?

maybe I am being silly.

Darren

[S4TAN]

I'm gonna ask an uber-dumb question on coilovers ... but here goes anyway (don't laugh!): the further up (towards the wheel arch) you move the spring perch on the c/o strut the higher you raise the car? And conversely, the lower the spring perch is on the c/o strut (towards the ground) the lower the car sits?

Yes? .... No ?

[DavidT]

Measured from the highest point inside the wheel arch to the ground

is it easy to do that? would the top of the arch (outside) not be more easy?

maybe I am being silly.

Darren

Yes, sorry, thats what I meant, the edge of the wheel arch at its highest point

[DavidT]

I'm gonna ask an uber-dumb question on coilovers ... but here goes anyway (don't laugh!): the further up (towards the wheel arch) you move the spring perch on the c/o strut the higher you raise the car? And conversely, the lower the spring perch is on the c/o strut (towards the ground) the lower the car sits?

Yes? .... No ?

Yes, correct, its just winding the spring up & down, it does not affect the spring rate, just the ride height & the suspension geometry.

[S4TAN]

Phew - thanks Dave!

So, answer me this then: my passenger side rear c/o spring perch is wound right down to near the end of the strut (the end nearest the ground), in fact about 2cm from the end... and my drivers side rear c/o spring perch is set higher, i.e. about 5cm from the end of the strut ..... yet my bloody car is 1cm lower at the rear on the drivers side than it is on the passenger side! (passenger side = 65cm from the highest point of the rear wheel arch edge to the ground, and drivers side = 64cm from the highest point of the rear wheel arch edge to the ground!!! Aaaarggh! WTF???)

[DavidT]

I'm not sure, perhaps the springs are not exactly the same heights ? seems unlikely though! eh ? or the shell is twisted only kidding. Is the tyre flat ? what are the fronts set to ?

[S4TAN]

No twisted shell (only the driver is twisted )

No flat bloody tyre either you cheeky git!

Front c/o's are dead even and sit perfectly level with each other ....

Weird no?

[MCB]

Julian mate that is rather strange only thing I can think of is a weak spring? Ball ache I know could try swapping them side to side and see if the situation is reversed - if it is obviously it is the spring.

I'll ask my boingy sig babe if she would like to give you a hand if you like.

[S4TAN]

Yo Paul, wassup man?

I'll ask my boingy sig babe if she would like to give you a hand if you like.

Yeah - f*ck the coilovers, she can take my mind off the weirdness ....