Car Advice

Why are the wheels on that car splayed out?

22 May 2017

Robert Pepper 13

Ever see a car with wheels like the one in the picture above? The wheels are splayed right out… Why?

NOT A LOT OF PEOPLE KNOW THIS, but the wheels on your car are almost certainly not exactly vertical. For pretty much every car these days, the wheels are slightly tilted in towards the car. And yes, that’s by design not as a result of that last pothole you hit.

Whether a car wheel is designed to run vertically or tilt slightly inwards or outwards is known as camber – a slight tilt out is positive camber, and a slight tilt in is negative camber. The angles in the diagram below are exaggerated for clarity:

Some degree of negative camber is normal for even the dullest of cars, and a bit more is usual for sportscars, and a bit more again for racecars. This is because when a car corners weight is transferred onto the outside wheel, so with negative camber the outside of the tyre becomes flatter to the road.

Next time you see a sportscar with wide-ish wheels – say a BMW M3 – have a close look, or check out the front wheels of a V8 Supercar, and you’ll see significant negative camber. As a very rough rule, the faster a car is likely to drive around corners, the greater the negative camber.

Now a “stanced” car is when the wheels have very significant and noticeable negative camber, like this:

Stanced cars require wheelarch flares or bodykits so the wheels are at least partially covered by bodywork as required by the law of the land and basic human decency. Stanced cars are also usually slammed, which does not refer to the contact of palm against forehead but to the excessive lowering of the vehicle so it is nearer the ground. The objective here is ‘hellaflush’, which doesn’t refer to a toilet and a bucketful of water but means there is no, or only minimal gap between the wheels and wheelarches, or body and ground.

The other typical stance modification is a stretched tyre. This is where you take a tyre, look up the manufacturer’s maximum permitted wheel width for that tyre, say “yeah, but nah”, and then fit the tyre to a wheel significantly wider than allowed by either the law, intelligence or good taste.

So you may wonder why stance exists. The answer is simple; for the appearance.

Many of the cosmetic changes people make to their cars do not affect performance and therefore the rule of ‘each to their own’ applies, but your average stanced car is rolling its way to a disaster, similar to a drunk lurching along the side of a rural country road at night in the rain, while wearing black, on a skateboard.

Stance can be summed up as – in excess, you make a mess. Imagine your perfect pizza with just the right number of toppings, and then add 25 more toppings, one of which is diced kangaroo poo. That’s stance, and this is why it’s a terrible idea:

• Braking – the tyre is designed to have its contact patch flat or nearly flat to the ground, not at the sort of angle where half of it is in the air. Basically, a stanced car has less grip so it takes longer to stop.
• Tyre wear – the inside of the tyre will wear out very quickly. Motorcycle tyres are designed to run at extreme angles, car tyres are not. You’re not helping your chances of avoiding a puncture either.
• Cornering – yes, negative camber helps with cornering grip. Stance-level negative camber is taking things to excess; instead of having a latte to perk you up, instead you drip some hot water into a jar of Nescafe, give it a stir and tip it down your throat. Lots of very clever engineers have spent a lot of time working out complicated equations concerning roll centres, coefficients of friction, weight transfer, yaw angular inertia and a zillion other boring but important parameters. Then Sammy Stance comes along and does the equivalent of improving the Mona Lisa using crayons guided by half-literate forum posts written by people they’ve never met but still refer to as “fam”.
• Drivetrain wear – CV joints, wheel bearings, bushes and various other components have been designed to run at specific angles, clearances and tolerances. These parameters are routinely exceeded by excessive negative camber. When you stance your car it’s like being forced to sit on a two-inch barstool with your feet on the desk and hold a laptop between your knees, typing with your knuckles. Kind of odd that people inflict this pain on a car they refer to as ‘bae’.
• Ride – suspension needs up travel, down travel, and it’s all been designed by those clever engineers to work in harmony. Stanced and slammed cars massively reduce uptravel and increase or decrease moments beyond the wildest nightmares of the engineers. Effective modifications are not made with an angle grinder in one hand and a Facebook post in the other. And by running the tyre on its sidewall you are changing the tyre’s compression characteristics which feed into the calculations about unsprung weight…oh, never mind. And this suspension abuse does not contribute to grip.
• Steering – stanced cars often have problems actually reaching full steering lock because the wheels rub on the guards or because the geometry is out of limits.
• Electronic safety aids – the car’s electronics such a stability control, ABS, brake distribution, engine traction control and many more are extremely sophisticated, attempting to prevent death by understeer, oversteer or idiotsteer. However, they assume the car’s setup is close of the original design and does not resemble a Lego Technic model assembled by a group of five-year old kids powered by undiluted cordial. Stance reduces the effectiveness of your electronic safety aids which is a problem for you, your passengers and any people or property close to the stanced vehicle. Sadly, the full extent of the engineering vandalism will only be discovered in that tiny moment of realisation just before disaster.

So if you want a stanced car, be aware you’re making it significantly less safe, increasing mechanical wear and almost certainly rendering it illegal with the consequent effects on insurance and liability.