the Citroën C4 Cactus is a car which takes you back to school.
i mean this both literally, as well as metaphorically.
literally, because i have visited many schools with it, and i love to observe the responses of children - aged six to sixty - as the Cactus drives by: fingers point, heads turn, eyes light up, and hands wave.
metaphorically, because there are a myriad of ways that the Cactus brings home those abstract diktats from your physics classes from all those years ago.
remember that equation relating force to mass and acceleration? it will come back vividly once you realise the alacrity of the Cactus’s in-gear acceleration, despite it having only a naturally aspirated three-cylinder powerplant. it’s all down to a set of five well-chosen ratios in that semi-automatic gearbox, and a sprightly kerb weight of 975 kg.
like the best three-cylinder engines, the variably valve-timed DOHC and direct injected PureTech 82 loves to rev. precisely how high it’s revving, one can’t really tell, as the car has no tachometer; but that can all be part of the fun, as the engine and drivetrain feel unburstable. and while you’re revving that plucky engine to high heaven, another lesson from physics classes comes to mind - this time, the one about harmonics and resonance. unmediated by a turbocharger, the soundtrack of the PureTech 82 up and down the rev range evokes memories of classic air-cooled 911s.
but with no turbocharger and only three cylinders, how can the Cactus hope to keep up in the daily commute? cue the law of conservation of momentum. like the best Citroëns, the C4 Cactus rewards considered inputs and forward planning. because of its relatively high power-to-weight ratio, the Cactus gains momentum easily, and you soon learn to do what you can to maintain it. if you are diligent, the driving experience becomes more rewarding and you’ll find yourself a better - smoother - driver.
from the conservation of momentum, to moments and vectors. although the C4 Cactus is available with a variety of engines, to my mind, the PureTech 82 hits the sweet spot. being a petrol, it is lighter than an equivalent diesel - plus, don’t forget, there is no encumbrance of a turbocharger.
this means that C4 Cactus PureTech 82 has the best front : rear weight distribution of any Cactus. more significantly, its weight distribution over the front and rear axles is as close to darn near equal than practically any other modern Citroën - range-topping flagship DS 5 included.
again, like the best Citroëns, the C4 Cactus can be introduced to a corner with the most delicate of inputs on the steering wheel, and it will doggedly track a steady line of your choosing - often without you having to even brush the brake pedal - at some really rather uncanny velocities.
much ink has already been spilt by motoring hacks across Europe on the other merits of the Cactus - from its seats, to its packaging, and suchlike. Autocar has taken one to a Spanish desert, and TopGear has trekked a glacier in Iceland. The Cactus is not only built to take a great deal of punishment, but it communicates this almost masochistic streak quite clearly to the driver. The car really does feel unburstable, and the clearly paradoxical way in which it cocoons its occupants in a cushy soundscape of three-cylinder thruminess calls to mind true Citroëns such as the 2CV and GS.
and thus we come to the signature feature of the Cactus - the Airbumps.
if there ever were a car designed to help us understand Newton’s Third Law of Motion, the Citroën C4 Cactus is it.
because it is as philosophical as it is unassuming, i count the C4 Cactus up there with the greatest Citroëns. and that’s why i’m buying one.