Alfa Romeo

Why Ball Joints in DeDion Caster Arms

As designed, the DeDion chassis uses a caster arm that is riveted or bolted to the upper control arm on one end; the other end is anchored to the chassis by a big soft rubber washer sandwich.

The bolted end (or riveted) is a VERY hard joint allowing no movement, and no attenuation of shock and vibration. Consequently, the chassis designers overcompensated at the forward end adding extra resiliency and movement via the two big, squishy washers that serve to tie that end to the car’s unibody. This works out well for the ride portion of the "ride/handling compromise", but is viewed by many as too much compromise in the handling side of the equation.

Those familiar with the front suspension design of the 105 chassis will realize that Alfa used the exact opposite tack when that car’s front end was designed. The forward end of the caster rod is "hard", using a ball joint to give ball and socket accuracy to the movement at that end. The end attached to the upper control arm uses a very soft rubber bushing (in fact, a lot of that bushing is air). Owners of these 105 and 115 chassis have had access to polyurethane bushings to stiffen up the joint at the control arm end.

GTV6 and Milano drivers searching to add more precision to the front end alignment and consequently their cars' handling also have access to polyurethane substitutes for the holey/squishy rubber washers. This does help a great deal, and of course these parts last a lot longer than the OEM rubber pieces.

However, there is a contingent looking for more control, and more precision in their front end setups. For these drivers, we have developed a kit that allows the adaptation of the 105 chassis ball joint to the DeDion chassis. The only mods required are the drilling of 2 bolt holes per side. The nice thing about this mod is that it is completely reversible. Since the front of the car has not been cut up, the car can be returned to the OEM configuration if so desired. No harm, no foul.

The "squishy rubber washer" end unscrews from the caster arm, and threaded ball joint ends thread directly back into them. A little visit to the alignment shop, and you are good to go.

Click here for photos and ordering info!

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