What does G-sum mean in track data?
G-sum is one number that combines how hard the car is braking, accelerating, and turning. It makes gaps easy to spot. If one lap has a big dip in the middle of a corner and another does not, that is a good place to start looking.
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The main idea
Think of G-sum as a highlighter. It makes the busy parts and the empty parts of a corner easy to see. Once you find a gap, go back to the map, speed, and delta to understand whether it actually cost time.
What to look at
- Peak and sustained Combined G
- Dips during phase transitions
- Differences at the same track location
- The longitudinal and lateral components underneath it
Try this
- Compare clean laps in similar conditions
- Locate a delta difference first
- Inspect Combined G through that segment
- Separate braking, cornering, and acceleration components
- Check whether the pattern repeats
Keep in mind
The number comes from how the whole car moved. Hills, banking, bumps, aero, tires, setup, and the way the sensor is mounted can all change it.
FAQ
Is G-sum the same as a friction circle?
G-sum is one magnitude value over time. A friction circle plots longitudinal against lateral acceleration to show direction and envelope shape.
Should I maximize G-sum everywhere?
No. Straights, shifts, setup phases, and some transitions naturally have lower values. Optimize the segment outcome, not a constant number.