GTA-R Front Upright

Developed to eliminate the brake pad “knock back” flaw in the 105 / 115 series front suspension these CNC machined billet uprights have resulted in one of the single biggest improvements for performance driving.

Originally designed uprights have relatively small diameter spindles for mounting the front hub and disc assembly which suited the standard factory wheel and tyre package. When used with modern tyres, the cars suffer from a long brake pedal after going through a series of corners (either on the road or track). This requires the brake pedal being pumped once to get the bite point back to the correct pedal height, this effect is known as pad “knock back”. This occurs when the spindle flexes in the upright due to the loadings from the wheel and tyre, resulting in the disc being able move beyond its normal axis, thereby forcing the brake pads away from the discs and causing the long brake pedal.

To tackle this issue, we have completely redesigned the uprights using a larger diameter spindle and a more robust fitment area where they interface with the upright in order to significantly increase rigidity.

While redesigning the uprights, we also took the opportunity to address the pickup geometry of the upper and lower ball joints. With careful analysis and computer simulation of the KPI, scrub radius with our 7×15” GTA wheels, roll camber correction factor and roll centre height, we have modified the upper and lower ball joint locations to optimise all these important suspension kinematic factors.

The benefits of this redesign is handling with a faster transient response times in direction change, improved tyre temperature distribution across the tyre face, reduced tyre wear, steering effort and kick back from the steering in oversteer condition.

Steering weight is transformed, making sticky track day Yokahama AD08 tyres feel like 185 section road tyres at parking speeds, whilst there is less torque in the steering during oversteer corrections.  The front of the car is now even more precise and better conveys the limit of adhesion through the steering to the driver.

These uprights are designed in conjunction with our top specification GTA-R front suspension components in order to extract the very best out of the cars.  That means they need to be fitted with our geometry kit and our titanium top wishbones. Due to the modified upper and lower pickup positions, these uprights must be used in conjunction with our steel angled quick steering arms (not our billet aluminium straight versions) in order to retain the correct bumpsteer geometry. These uprights have been optimised to fit with our 6-pot brake kit and have 1750/2000 (89mm) caliper bolt spacing. They can be used with other brakes that are compatible with 1750/2000 uprights although you may need to modify the disc offset.

Supplied as a pair with a matching set of wheel bearings and hub oil seals to work with the factory wheel hubs. Also supplied with a pair of short outer track rod taper pins and a range of spacer shims to allow you to optimise your bumpsteer which are designed to be used with our steel quick steering arms and rose jointed track rod kit (available separately).