Wheel Alignment Rants

I think in the last 6 years generally I have had less changes to the kind of wheel alignment that I run then I do changes to my rims or exhaust or other settings of the car in a typical year.

my old civic EG6

I think during the era of my first proper car for the track, my old EG6, some gurus handed down to me some secret wheel alignment settings only which in 20 odd trackdays, did I tweak ever so slightly

Alittle toe in on the rears to help the braking, 1 degree less camber on the rear than the fronts so that the car could still slide around or be chucked into a corner. but that was about it.

My point that perhaps I still havent quite reached, is that why are we so fixated with all these arbitrary numbers for our wheel alignment, everyone I know seems to run some sort of stagger on their wheel alignment, in nice round numbers too, most people seem to be running a 1 degree difference between the front and rear, be it a Honda Civic or an Evo or an STI,

From a theoretical stand point, the reason why we run more negative camber on the track, is because a tyre actually has the most grip when it has 0′ degree camber. However, when a car corners, the inner wheels (meaning the wheels on the inside of the turn, Left turn, left wheels) begin to decamber (becomes positive camber). Therefore we run some negative camber so that during a turn the inside wheel becomes 0’degree camber.
positive, negative and zero camberCars running on stock suspension (soft with little negative camber and probably lots of body roll) will see excessive tyre wear on the outer shoulders and probably some understeer wear on the fronts.

tyre wear 1

tyre wear 2

Having said all that above some modern asymmetric tyres are designed to have more grip on the outer shoulders, so a little bit of lean outwards might prove to be alittle quicker around the track, of course not so much til the shoulders wear out!

asymmetric tyres

How do I know how much camber I need to run?

well besides listening to the guru’s,

Start by measuring your tyre temperatures, ideally after a quick cleanly driven hot lap around the circuit, not doing a cool down lap and coming straight into the pits to measure the temperatures. And measure it with a tyre pyrometer and not an infra-red gun that I see so often, a pyrometer reads the core temperature inside the tyre, not the surface temperature as that is not a good measure of how hot the tyre compound is.

Once you’re done measuring, quickly head out to finish that cooling down lap.

Ideally we should be looking at as small a temperature spread between the inner shoulder, middle and outer shoulder, with the inner shoulder being the highest, getting slightly cooler to the outer shoulder. This is because in the end we can not avoid running on the slightest bit of front camber and due to the long braking zones on Sepang, alot of heat is built up on the inner shoulder.

Based on the heat in the tyres, camber should then be adjusted for more or less negative camber. Tyre air pressure and suspension settings should not be changed too much in this time.

Ok I have to end here cos looks like we’re crossing over into the realm of car suspension setup which will leave me here on my computer typing for weeks!

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