The Spa 24 Hours is one of the biggest special events on the iRacing calendar. Twenty-four hours at Circuit de Spa-Francorchamps with unpredictable weather, a full GT3 field and a race long enough that strategy and consistency matter most.
This guide covers everything you need: which car to pick, how to manage fuel and tyres, how to prepare for weather changes and how to set up for long-run balance rather than one flying lap.
Car choice: BoP and long-run pace
Balance of Performance is updated in the week of the race and can shift the pecking order before the event. Always check the latest BoP before committing to a car. With that said, some cars naturally suit Spa's demands over a long stint and some do not.
The core principle at Spa: pick a car that stays balanced as the tyres wear. The circuit has so many sustained high-speed corners that a car which loses rear stability over a stint will lose you laptime and can even end your race. Qualifying pace is a secondary consideration. Long-run pace and tyre life decide the Spa 24.
Cars to consider:
The Ferrari and Ford are among the outright fastest without BoP applied. The Ferrari suits Spa particularly well with a good balance through the high-speed sections and consistent over a long stint. The Ford's strength is straight-line speed, which produces strong single-lap pace, but it may drop off more than the balanced cars over a full run. It is also a car that can be taken away quickly by a BoP change.
The Aston Martin has strong medium and high-speed mid-corner grip, which is exactly what Spa's sustained fast corners demand. It stays balanced over a long run and is one of the more comfortable cars to drive for hours.
The BMW is a good balance choice that holds up well over the long run — predictable, consistent, and less tyre-dependent than most of the field.
The Mercedes is very comfortable to drive over a stint. Not the outright fastest without a strong BoP, but a solid endurance pick if the numbers favour it.
Cars to be cautious about:
The Porsche will likely show a notable gap between qualifying pace and long-run pace. It relies on its tyres more than the cars above, which works against it on a circuit with this many sustained high-speed corners. Avoid it unless BoP heavily favours it.
The Lamborghini and Audi can be twitchy around Spa and need a good BoP to be viable. Without it, they are hard work for 24 hours.
The Corvette lacks mid-corner rotation. Unless it is given a very favourable BoP, it is not a strong pick here.
The Acura is in the same bracket, unless it is genuinely flying on BoP numbers, it is not the right choice for this event.
The McLaren does not do too badly, but it struggles in Spa's very long, sustained corners. Not a poor car, just not the first choice here unless BoP makes it one.
The initial BoP was released by iRacing on the 2nd of July: 
Strategy: save a lap, skip a stop
Spa's pit lane is very long. A splash and dash costs far more time here than at most circuits, which makes fuel saving more valuable than at almost any other event on the iRacing calendar.
Saving one lap of fuel per stint is almost always worth it. Lifting slightly before braking zones like T1, Les Combes and the Busstop and easing onto the brakes rather than hitting them flat can extend each stint by a lap without a meaningful pace penalty. Over a 24-hour race, one saved lap per stint can remove a full pit stop from your total. Given the Spa pit lane, that is a large time gain. Calculate how many laps the race will be based on average laptime (or take a look at the race from last year) and calculate how many stints are needed in the race. Now calculate if you can save out a full stint if you go a lap longer.
This technique also protects tyre life. A small lift before braking reduces the tyre stress, and thus tyre heating. This way you are making the tyres last longer at the same time as saving fuel.
Full fuel every stop. Calculate how many laps you can do per stint, how many stints remain, and whether saving one lap per stint removes a stop entirely. That calculation — more than any pass you make in the opening hours — is what wins the Spa 24.
Tyre changes: change tyres at every full pit stop. At roughly 20 seconds per tyre change in GT3, there is almost no scenario where carrying worn tyres saves enough time to matter. The only exceptions are a splash and dash at the end of a stint due to incoming rain. When the night falls and the track temperature gets very low, it might also be a case of doublestinting the tyres.
Setup: balance over tyre wear
The fundamental challenge for a Spa endurance setup is that the car needs to be drivable and consistent as the tyres wear. A setup that is perfectly balanced on fresh rubber but nervous on worn tyres will cost you time every single stint in the second half of the race.
Wing: Spa runs a low-medium wing configuration. Long straights at Kemmel, Blanchimont and into the bus stop mean too much rear wing costs you every lap. But Spa also has sustained high-speed corners where rear stability matters. Trim the rear wing, but leave enough that the rear stays planted through Pouhon and Blanchimont. For endurance pace specifically, run slightly more wing than qualifying trim. The stability on worn tyres in the second half of each stint is worth more than the straight-line gain.
Rear stability as tyres wear: as the tyres degrade, the rear might become progressively looser. Build rear stability into your baseline with slightly more rear wing, slightly softer rear springs, a small amount of rear toe-in. This way the car is still manageable in the final 20 laps of a stint. That is when mistakes happen and a stable car in that window is the difference between a clean stint and a wall.
Weather
Spa's weather is genuinely unpredictable. The race can run dry for 18 hours and then get soaked at 3am, or it can rain within the first stint. You cannot prepare for the specific forecast. You can prepare for the transitions.
The most dangerous moment in any wet-dry or dry-wet transition is the first lap on the new tyre. If it starts raining while you are on slicks, the car might have good grip in one corner, but absolutely zero grip in the next as the track becomes more wet. Watch the weather radar on the HUD and do not wait until the car is sliding to decide to pit for wets. On a long track like Spa, you don't want to be a lap too late with changing to the right compound.
Cold slick tyres in conditions where the track goes from wet to dry are the other trap. Blanchimont, Eau Rouge and Pouhon should be flat in most conditions but when the track is drying there will be a clear dry line and a clear wet line. Drop a slick tyre on the wet line by accident or when lapping slower traffic and the car will start sliding of the track without a warning. It is therefor important to make the consideration of lapping traffic and overtaking cars when making the decision to go to slicks. You might be fine while staying on the racing line, but keep in mind that you might have to leave that line when overtaking cars.rst.
The rig that handles 24 hours
Driving for multiple hours at Spa puts demands on a cockpit that gives you comfort and confidence. Fatigue is a performance variable where a seating position that is fine for 30 minutes becomes a liability over four hours, and going into Blanchimont or Eau Rouge while fatigued can end your race in a heartbeat.
Rig rigidity matters because Spa's force feedback is communicative. You will feel the kerbs at the bus stop, the compression through Eau Rouge, the rear starting to slide on worn tyres at Pouhon. A rig that flexes with the wheel forces masks that information. At 3am on hour 18, that information is what keeps you out of the barriers.
- SIMGASM Hobby simulator — 40×40 profile, a stable and consistent cockpit that does not change over a long session.
- SIMGASM Club simulator — 80×40 profile, adjustable for any GT3 wheel and pedal combination. The go-to for most serious iRacing endurance builds.
- SIMGASM Sport simulator — 120×40 profile, stronger wheel mount, integrated cable pass-throughs for a clean multi-device setup, and enough adjustability to dial in a seating position you can maintain across a full stint.
- SIMGASM Pro simulator — 160×40 profile, zero flex. Consistent feedback from lap one to lap five hundred.
A load cell pedal like the MOZA CRP2 matters here specifically because the fuel-saving technique where you want to be easing to 70–80% throttle before the braking zone requires being able to feel and hold a precise partial throttle position. It is way more difficult to do that consistently with a potentiometer pedal.
FAQ
What is the best car for the iRacing Spa 24 Hours? Check the latest BoP before committing. With even BoP, the Ferrari, Ford and Aston Martin suit Spa's long-run demands best. The BMW is a reliable all-rounder. Avoid the Porsche, Lamborghini, Audi, Corvette, and Acura unless BoP heavily favours them. Those cars drop off more over a long stint than the balanced cars.
Should I save fuel at the Spa 24 Hours? Yes. Saving one lap per stint is almost always worth it given how long the Spa pit lane is. A saved lap per stint can remove a full pit stop from your race, which at Spa is a significant time gain.
When should I change tyres? At every full stop in normal conditions. At roughly 20 seconds per tyre change, the time cost is easy to make up over a full stint. Only skip tyres on a splash and dash or if rain is imminent and another stop is coming shortly.
How do I handle the Spa weather? Watch the radar in the iRacing race client and do not wait until the car is sliding to pit for wets. When on fresh cold tyres in changing conditions, take plenty of margin. Losing a couple of seconds per lap is still better than having 3 minutes of repairs.
How do I overtake safely in a 24-hour race? Use the straights into Les Combes and into the bus stop. Do not attempt passes through the infield or through Spa's high-speed corners. The time gain is not worth the risk over 24 hours.
