105 Caster issue help

[Nick Shardey]

Hi all,
Ok it's a 64 step with all the usual Vin suspension parts. I have it set up with 3% neg camber a little toe in but although there is plenty of adjustment on the castor arm but there is no room due to the upper camber arm nearly touching the body, so I can't get any positive. It's great on the turn in side but at high speed it's like a shopping trolley. Any ideas?

thanks Nick

[Colin Byrne]

I've had a lot of trouble with high speed stability in my car. I haven't found the "golden bullet" but there are a few things that have helped

-   Ensure all the tie rod ends on the steering arms are in good condition
-   Check for slack in steering box, this can sometimes be fixed by adjusting the shims at the top cover.
-   Check carefully for any chassis cracks around the steering box and the idler arm
-   Reducing bump-steer
-   Replacing the original rear wheel bearings with wider double row ones, this helps to stabilize the rear wheels and probably made the biggest difference in my car

[Nick Shardey]

Thanks Colin,

I've done the rear bearing upgrade but the rest all sound like excellent ideas.

Cheers,

[monoman]

Hi Nick,

I've fitted the Alfaholics suspension geometry pack, see http://www.alfaholics.com/racing_and_competition/performance_and_racing_parts/suspension/document_459_117.php which effectively moves the lower ball joint pivot much further forward, thereby increasing castor significantly.  I'm currently running just over 5 deg of castor.  I could probably squeeze out another 1/2 deg before the top arm starts rubbing.  The kit also provides zero bump steer (measured) within normal wheel travel, and raises the roll centre on lowered cars.

It's kind of weird driving a 105 with a rock steady steering wheel - no jiggling and wiggling over bumps.  Of course the extra castor does make the steering a little heavier, as does the small wheel and the quick ratio steering arms.

Cheers