KTRace steering arm kit to reduce bump steer for Lotus
The KTRace steering arm kit was developed to reduce unwanted track changes during compression and rebound – known as bump steer – to a constructively achievable minimum.
Especially in lowered Lotus vehicles, the original steering geometry and the angles of the involved suspension components change. As a result, the track can change significantly during spring movement. The vehicle then reacts to bumps, load changes, and curbs with unwanted steering movements and appears restless or difficult to predict.
The KTRace steering arm kit corrects the steering kinematics and noticeably improves driving precision, stability, and feedback.
What does bump steer mean?
Bump steer refers to a change in track that occurs solely due to the compression or rebound of a wheel – without the driver moving the steering wheel.
With an unfavorable steering geometry, the wheel can independently switch to toe-in or toe-out during the spring movement. This can lead to the following effects, among others:
Unstable driving behavior on bumps
Unwanted steering movements during compression
Nervous behavior at high speeds
Reduced stability when braking
Imprecise steering response
Difficult vehicle control when driving over curbs
Changing driving behavior depending on the spring travel
The smaller the change in toe over the entire usable spring travel, the more precise and predictable the vehicle reacts.
Especially important for lowered vehicles
The standard steering kinematics is calibrated to the original vehicle height. When the vehicle is lowered, the angles of the steering arms, tie rods, and other suspension components change.
As a result, the tie rod can describe a movement arc that no longer matches the wheel suspension during compression and rebound. The consequence is a significantly stronger change in toe over the spring travel.
The KTRace steering arm set adjusts the geometry to the changed vehicle height and reduces this unwanted effect to a minimum.
Improved driving precision
With the optimized steering geometry, the set toe remains significantly more constant during the spring movement. This allows the vehicle to react more calmly and precisely to road irregularities, rapid load changes, and high lateral accelerations.
The improvement is particularly noticeable in:
Lowered vehicles
Sport-tuned suspensions
Semi-slick and motorsport tires
Fast country road driving
Track days and racetrack use
Frequent curb riding
High speeds on uneven roads
Advantages
Reduces toe changes during compression and rebound
Corrects the steering kinematics of lowered vehicles
Minimizes unwanted self-steering movements
Improves driving stability
More precise steering response
Smoother behavior on bumps
Better feedback through the steering
More predictable handling at the limit
Especially suitable for sporty road vehicles and track days
A sensible addition to coilover suspensions and lowering kits
Suitable for
Selected Lotus models according to the offered vehicle variant
Especially recommended for vehicles with lowering or height-adjustable suspension
Exact compatibility must be checked before ordering based on vehicle model, year of manufacture, hub carrier design, suspension, and set vehicle height.
Scope of delivery
1 × KTRace steering arm set to reduce bump steer
Other suspension components and installation services are not included in the scope of delivery unless explicitly listed as part of the chosen variant.
Important installation and adjustment note
The installation involves safety-relevant components of the steering and may only be carried out by a qualified specialist.
The following are absolutely necessary after installation:
Complete wheel alignment
Adjustment of the front axle alignment
Check of camber and caster
Check of clearance over the entire steering angle
Check of clearance over the full suspension travel
Check or measurement of the toe change during compression and rebound
The best possible result can only be achieved if the control arm set is adjusted to the actual vehicle height and the existing suspension configuration. Incorrect installation or axle adjustment can significantly affect driving behavior.