Bumper canards (also dive planes) are small wings attached to the front spoiler of a car for the purposes of modifying the aerodynamic characteristics of the car in a modest way.
The most common use of bumper canards is to increase front downforce on cars where the balance of traction is considered to be unfavourably biased towards the rear wheels. The bumper canards, once installed, provide additional downforce at the front of the vehicle, adjusting the balance of traction and thus improving the handling characteristics of the car.
Applications and technical information
Bumper canards in motor racing
Basic aerodynamic principles dictate that the downforce created by air pressure on a surface increases exponentially with speed, thus, as with many aerodynamic modifications the bumper canards are primarily suited to the high speed conditions of motor racing. More specifically, bumper canards are most likely to be installed on racing vehicles which are based on conventional road cars such as Stock Cars, Touring Cars and GT Cars where the car’s essentially stock bodies (designed for road-use) have not already been designed to provide optimum aerodynamic characteristics for track use.
Bumper canards in street use
In common with many other modifications made to competitive track vehicles, bumper canard have in recent years begun to be seen on conventional road-going vehicles (most commonly on modified Japanese sports coupes and road-going counterparts of Stock Cars and Touring Cars).
Perhaps one of the most significant driving forces behind adoption of bumper canards as a common modification to road-going vehicles is their widespread uptake in Japanese and US street racing the like of which inspired the successful Hollywood pentalogy: The Fast and the Furious, though whether in many instances the film was inspired by real cars (and culture) or vice versa is hard to discern.
Purely cosmetic or performance enhancement?
Whether bumper canards installed on road-going vehicles are a genuine performance enhancement or simply a cosmetic modification is sometimes contested.
Unarguable is the fact that they are in common use on track vehicles whose operators would not install any modification not considered to improve the performance of their vehicle. Recreational car modifiers could successfully argue that they garner the same benefits, albeit perhaps to a lesser extent as their track counterparts, distinguishing this modification from purely cosmetic modifications (referred to as "Ricing" in popular car culture).
Materials and manufacture
Due to strength and weight considerations, bumper canards designed for race use were originally fabricated from carbon fibre reinforced plastic (CFRP). The high strength to weight ratio and desirable appearance ensures that bumper canards currently sold for road-going cars are often also made from this material.
Bumper canards are generally made either as a flat sheet ‘triangles’ with additional edging strips (for mounting and directing airflow) or as a bespoke moulded component utilising the strength of the material and sophisticated match tooling to integrate the necessary upturns and curvature into a single piece of carbon fibre.
Bumper canards are relatively simple to install and are often available with slightly different curvature to match the shape of the front spoiler of the vehicle to which they will be fitted. They are most commonly installed in sets of four, a larger and a smaller canard on each side of the bumper with the larger canard at the bottom.
Commercially available bumper canards include a ‘mounting kit’ which amounts to a set of high quality bolts which fasten through holes drilled in the front bumper to accommodate the canards. Rawl bolts are a clever mounting method used by one manufacturer which means that installers to not need to access the inside of the front bumper to add or remove the canards whilst also benefiting from the anti-vibration effect of the rubber bolt.
Canards should be installed with the large face at the front and aligned such that they do not protrude outside the existing outer line of the car body (so as to avoid creating a safety hazard). This ensures that the main area of wing surface is as far forward on the vehicle as possible (where it will exert more force on the front of the vehicle).