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See also: 9 Clever Car Hacks You Just Can’t Live Without
Cars are some of the most complex forms of engineering as they combine numerous different types of technology, so it's easy to understand how bad information can float to the surface - let's look at the facts surrounding five performance modifications which might not be a good idea.
I know we’re all supposed to be loving and kind and respect one another’s tastes, but I don’t find there to be anything attractive about sacrificing a vehicle’s performance in the name of looks. For the same reasons, I don’t understand why you’ll often find fake pockets on women’s clothing, or why some people insist on wearing sunglasses inside dimly lit restaurants. Enough ranting, let’s get on with five performance draining modifications:
1) Negative Camber
This is probably one of my favourites, because even after people are presented with facts they’ll deny it for eternity. Maybe they’re anti-vaccers too. I’m getting off topic again; let’s look at some data. The figure below is from Carroll Smith’s book Tune To Win.
The coefficient of friction between the tyre and the ground is perhaps a tyre’s most important characteristic - the higher the coefficient of friction, the more grip the tyre has. As you can see in the graph above, peak grip results from about -1.0 to -2.0 degrees of negative camber. It’s worth noting that this number will change based on the specific tyre and the lateral load it’s experiencing, for example cars running very high downforce may be able to get away with slightly more negative camber.
The highest negative camber I’ve heard of being used in motorsport is in Nascar. According to the competition director, cars can run as high as nine degrees for the outside front (they will race set at about -4.0 degrees, and lean in about 5 degrees), while keeping the rear camber at -3.6 degrees or less (inside tyres run positive camber). You have to keep in mind these cars are running on steep banked ovals with high downforce at incredibly high speeds, so the g-forces are greater than you’ll see on road cars, enabling use of higher camber angles.
Outside of motorsport, other examples include GM recommending -1.5/-1.0 degrees (front/rear) for track preparation of the Camaro Z/28, or the Nissan GT-R running approximately -1.0 degrees.
The point is, if you can easily, visibly spot negative camber on a tyre, chances are it’s a bit excessive. Aside from a reduced contact patch and thus less grip (both laterally and longitudinally), heavy negative camber will also result in uneven tyre wear and uneven heating of the tyre on a track.
