For the drivers, Spa Francorchamps is a test, and for the strategists, it’s a nightmare – the weather in the Ardennes is wildly unpredictable. It can be bone dry at the far side of the circuit, and flooded in the pits.

The hairpin, La Source, usually catches out a couple of cars at the start. Eau Rouge is at the foot of the hill that follows, and despite some re-working it’s still an awesome challenge, taken in top gear at 300km/h and with a blind crest. At -3.5G it’s the only corner in F1 to offer negative G-force.

The straight this leads into is long and kinked, and the best overtaking opportunity for cars that can draft the one ahead. From La Source to Les Combes, the cars are on full-throttle for 23 seconds, so this is a real test of engine durability.

From Les Combes – the key passing spot – it’s then downhill all the way through the fast and demanding Pouhon to Stavelot, where the original circuit is rejoined on the ascent to the pits. Then there is the mighty Blanchimont, curving through the trees in top gear, before slowing for the chicane.
 

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Despite its fearsome appearance, Spa is a fairly average circuit for retirements but the exception is the opening lap. As noted above, as the cars funnel into La Source hairpin it’s unusual if the field escapes undamaged and even if they do, there is always the twisting Les Combes to take care of a few. With 5.8% of the starters failing to complete a lap in the last five years, Spa has the fourth toughest opening lap on the calendar.

Engine demand:		Mechanical retirements:		10.5%
Tyre wear:		Accident retirements:		10.5%
Brake demand:		First Lap retirements:		5.8%
Downforce level:		Safety car deployments:		0.75 per race

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Retirements and safety car deployments based on last five years.
Retirements are a percentage of all cars starting the race.
Accident retirements covers accidents, collisions and drivers spun out of the race
Other data courtesy of AT&T Williams F1, Lotus Renault GP, Pirelli Tyres and Brembo Brakes