Roll Centre Adjuster
Ask any aftermarket enthusiast, “What is the one thing you’ve done to improve your handling?” They’ll almost certainly tell you; suspension. True to that statement, suspension is a beneficial modification that significantly improves handling, helping relieve understeer, lessen body roll, lower the vehicle’s overall CG (Centre of Gravity), as well as improving road feel.
Leaving chassis lightening and spot welding to race cars, another common modification amongst road-going cars that help to further aid aftermarket suspension would be chassis strengthening. These come in the form of strut and anti-roll bars, which further help stiffen the rigidity of the vehicle. While these help alleviate even more body roll and improve handling characteristics, one point is still commonly often overlooked in the quest for ultimate handling; the roll centre adjuster.
The roll centre adjuster is an item that is both hated and fondly loved by the people who pursue perfect handling. Located at the knuckles of a vehicle’s lower arm, it is a small ball joint stem item that most overlook and considered insignificant to handling. Albeit expensive and seemingly ineffective, there are aplenty benefits if roll centre adjusters are installed on a lowered ride.
To explain the roll centre adjuster, it is what is says; an item that helps adjust the centre of a vehicle’s body roll. The roll centre adjuster is made to match a suspension system, helping to square a vehicle’s centre of gravity. Every vehicle has stock roll centre adjusters installed to perfectly match the stock suspension’s ride height. Should one change to a set of aftermarket suspension while retaining the original ride height, the stock roll centre adjuster is of no issue...
However, if one were to lower the vehicle after the change (which will most certainly happen), the dynamics of the roll centre adjuster will diminish. This is because the lowered vehicle height will alter the vehicle’s body centre of gravity, causing the lower control arm that was once sitting almost perpendicular with the road, to bend awkwardly upwards. This is due to the difference in height with the stock roll centre adjuster’s stem. This will cause the centre of gravity to be distorted when the vehicle rolls left or right. Another problem that may arise from this is the quick deterioration of suspension bushings, which is caused by prolonged work at a strained angle.
To fix this particular lowered ride issue, an aftermarket roll centre adjuster with a taller stem height has to be installed. This helps realign the lower arm to be more or less parallel with the ground, keeping the vehicle’s centre of gravity in proportion with its new ride height, allowing the suspension and tyres to be fully maximised in a corner. This is especially effective for track enthusiasts, who are looking to further increase tyre traction and to shave off those precious milliseconds. Do take note though; there are a variety of roll centre adjusters available in the market for a various degree of applications. So choose your desired roll centre adjusters wisely to cater to your individual cornering needs.
