Front Upright Modification- Increased Scrub radius/Mechanical Trail (Giulia)

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Front Upright (Motorsport) Modification- Increased Scrub radius/Mechanical Trail (Giulia)

Increase Mechanical Trail to Improve Road Feel and Stability

  • The modification of the uprights or goosenecks, in which the hubs are machined back 6.4 mm to increase mechanical trail
  • This also decreases the wheelbase by 6.4 mm. This is convenient for the square set-up, because the slight tire rubbing in front part of fender is lessened by moving the wheel back
  • The machine work was performed by an Indy and IMSA race machinist at Bobby Rahal's shop

Giulia QV mechanical trail thesis:

"The +6.4 mm mechanical trail (the distance in the side view from the steering axis to the center of the tire at the ground), increases the torque around the steering axis when the steering wheel is turned. It also increases the self-centering forces when the wheels are turned due to the larger moment arm created by the increased trail. The result is more steering wheel torque build up versus steering wheel angle which increases steering feel when cornering.”

To put it another way. Mechanical trail is one of the two important forces your wheels encounter. A long trail may make the driving experience easier, but a shorter trail typically allows for greater control. The reasons why this trail is positive are because: It ensures the wheel is essentially pulled.

Testing and Results:

  • More road feel via wheel feedback
  • A more measured car response vs driver input - car turn-in control vs steering wheel angle
  • Dialed out nervous jittery, floating steering
  • This is a true motorsport modification and feel


You can either send us your Uprights to be modified (2-3 weeks) or

You can purchase uprights for us to modify. 


(2) Upright Modification L/R (steel or CCM brakes) 2.0L or 2.9L

(8) SHCS M12x1.75x60

(8) pinch nuts M12x1.75,

(4) SHCS M12x1.75x75, caliper bolts NC

(4) 1" ODx0.25" long spacers, caliper spacers


The increase in mechanical trail provides the driver with more measured and confidence inspiring handling. The jittery Xbox video quick handling is dialed out, and road feel is increased for better input. 


Specific References