iRacing Telemetry Documentation

Position and Physics

Name	Unit	Type	Status	Description
Speed	m/s	float		GPS vehicle speed
Yaw	rad	float		Yaw orientation
YawNorth	rad	float		Yaw orientation relative to north
Pitch	rad	float		Pitch orientation
Roll	rad	float		Roll orientation
YawRate	rad/s	float		Yaw rate
YawRate_ST	rad/s	float	NEW	Yaw rate (sub-tick)
PitchRate	rad/s	float		Pitch rate
PitchRate_ST	rad/s	float	NEW	Pitch rate (sub-tick)
RollRate	rad/s	float		Roll rate
RollRate_ST	rad/s	float	NEW	Roll rate (sub-tick)
VelocityX	m/s	float		X velocity
VelocityX_ST	m/s	float	NEW	X velocity (sub-tick)
VelocityY	m/s	float		Y velocity
VelocityY_ST	m/s	float	NEW	Y velocity (sub-tick)
VelocityZ	m/s	float		Z velocity
VelocityZ_ST	m/s	float	NEW	Z velocity (sub-tick)
LatAccel	m/s²	float		Lateral acceleration (including gravity)
LatAccel_ST	m/s²	float	NEW	Lateral acceleration (sub-tick)
LongAccel	m/s²	float		Longitudinal acceleration (including gravity)
LongAccel_ST	m/s²	float	NEW	Longitudinal acceleration (sub-tick)
VertAccel	m/s²	float		Vertical acceleration (including gravity)
VertAccel_ST	m/s²	float	NEW	Vertical acceleration (sub-tick)

Note: Variables with _ST suffix provide sub-tick precision data for enhanced accuracy in physics calculations and data analysis.

Geographic Data (Legacy - 2015 Only)

Name	Unit	Type	Description
Lat	deg	double	Latitude in decimal degrees (deprecated)
Lon	deg	double	Longitude in decimal degrees (deprecated)
Alt	m	float	Altitude in meters (deprecated)

Engine and Vehicle Systems

Name	Unit	Type	Status	Description
EngineWarnings		irsdk_EngineWarnings		Bitfield for warning lights
FuelLevel	l	float		Liters of fuel remaining
FuelLevelPct	%	float		Percent fuel remaining
FuelPress	bar	float		Engine fuel pressure
FuelUsePerHour	kg/h	float		Engine fuel used instantaneous
ManifoldPress	bar	float		Engine manifold pressure
OilLevel	l	float		Engine oil level
OilPress	bar	float		Engine oil pressure
OilTemp	C	float		Engine oil temperature
Voltage	V	float		Engine voltage
WaterLevel	l	float		Engine coolant level
WaterTemp	C	float		Engine coolant temp
BrakeABSactive		bool	NEW	ABS system active

Shift and Power Systems

Name	Unit	Type	Description
ShiftIndicatorPct	%	float	DEPRECATED use DriverCarSLBlinkRPM instead
ShiftPowerPct	%	float	Friction torque applied to gears when shifting or grinding
ShiftGrindRPM	RPM	float	RPM of shifter grinding noise

Weather and Environment

Name	Unit	Type	Status	Description
TrackTemp	C	float		Temperature of track at start/finish line
TrackTempCrew	C	float		Temperature of track measured by crew around track
TrackWetness		float	NEW	Track wetness level
AirTemp	C	float		Temperature of air at start/finish line
AirDensity	kg/m³	float		Density of air at start/finish line
AirPressure	Hg	float		Pressure of air at start/finish line
WindVel	m/s	float		Wind velocity at start/finish line
WindDir	rad	float		Wind direction at start/finish line
RelativeHumidity	%	float		Relative Humidity
FogLevel	%	float		Fog level
WeatherType		int		Weather type (0=constant 1=dynamic)
Skies		int		Skies (0=clear/1=p cloudy/2=m cloudy/3=overcast)

Driver Change and Team Racing

Name	Unit	Type	Status	Description
DCLapStatus		int		Status of driver change lap requirements
DCDriversSoFar		int		Number of team drivers who have run a stint

System and Graphics

Name	Type	Status	Description
OkToReloadTextures	bool	NEW	Safe to reload textures
LoadNumTextures	bool	NEW	Load number of textures
CarLeftRight	int	NEW	Car left/right indicator
VidCapEnabled	bool	NEW	Video capture enabled
VidCapActive	bool	NEW	Video capture active

Pit Services and Repairs

Name	Unit	Type	Status	Description
PitsOpen		bool	NEW	Pit lane open
PitRepairLeft	s	float		Time left for mandatory pit repairs if repairs are active
PitOptRepairLeft	s	float		Time left for optional repairs if repairs are active
PitstopActive		bool	NEW	Pitstop currently active
FastRepairUsed		int	NEW	Fast repairs used
FastRepairAvailable		int	NEW	Fast repairs available
PitSvFlags		irsdk_PitSvFlags		Bitfield of pit service checkboxes
PitSvLFP	kPa	float		Pit service left front tire pressure
PitSvRFP	kPa	float		Pit service right front tire pressure
PitSvLRP	kPa	float		Pit service left rear tire pressure
PitSvRRP	kPa	float		Pit service right rear tire pressure
PitSvFuel	l	float		Pit service fuel add amount
PitSvTireCompound		int	NEW	Pit service tire compound

Enhanced Tire Management

Individual Tire Usage Tracking

Name	Type	Status	Description
LFTiresUsed	int	NEW	Left front tires used
RFTiresUsed	int	NEW	Right front tires used
LRTiresUsed	int	NEW	Left rear tires used
RRTiresUsed	int	NEW	Right rear tires used
LFTiresAvailable	int	NEW	Left front tires available
RFTiresAvailable	int	NEW	Right front tires available
LRTiresAvailable	int	NEW	Left rear tires available
RRTiresAvailable	int	NEW	Right rear tires available

Tire Set Tracking

Name	Type	Status	Description
LeftTireSetsUsed	int	NEW	Left side tire sets used
RightTireSetsUsed	int	NEW	Right side tire sets used
FrontTireSetsUsed	int	NEW	Front tire sets used
RearTireSetsUsed	int	NEW	Rear tire sets used
TireSetsUsed	int	NEW	Total tire sets used
LeftTireSetsAvailable	int	NEW	Left side tire sets available
RightTireSetsAvailable	int	NEW	Right side tire sets available
FrontTireSetsAvailable	int	NEW	Front tire sets available
RearTireSetsAvailable	int	NEW	Rear tire sets available
TireSetsAvailable	int	NEW	Total tire sets available

Camera System

Name	Type	Description
CamCarIdx	int	Active camera's focus car index
CamCameraNumber	int	Active camera number
CamGroupNumber	int	Active camera group number
CamCameraState	irsdk_CameraState	State of camera system

Tire Rumble Effects

Name	Unit	Type	Status	Description
TireLF_RumblePitch	Hz	float	NEW	Left front tire rumble pitch
TireRF_RumblePitch	Hz	float	NEW	Right front tire rumble pitch
TireLR_RumblePitch	Hz	float	NEW	Left rear tire rumble pitch
TireRR_RumblePitch	Hz	float	NEW	Right rear tire rumble pitch

Driver Controls and Adjustments

Name	Unit	Type	Status	Description
dcStarter		bool	NEW	Driver control starter
dcTearOffVisor		bool	NEW	Driver control tear off visor

Pitstop Adjustments

Name	Unit	Type	Status	Description
dpRFTireChange		float	NEW	Pitstop right front tire change
dpLFTireChange		float	NEW	Pitstop left front tire change
dpRRTireChange		float	NEW	Pitstop right rear tire change
dpLRTireChange		float	NEW	Pitstop left rear tire change
dpFuelFill		float	NEW	Pitstop fuel fill
dpFuelAddKg	kg	float	NEW	Pitstop fuel add in kg
dpFastRepair		float	NEW	Pitstop fast repair
dpLFTireColdPress	kPa	float	NEW	Pitstop left front tire cold pressure
dpRFTireColdPress	kPa	float	NEW	Pitstop right front tire cold pressure
dpLRTireColdPress	kPa	float	NEW	Pitstop left rear tire cold pressure
dpRRTireColdPress	kPa	float	NEW	Pitstop right rear tire cold pressure

Overview

This documentation covers the iRacing telemetry API evolution from the original 2015 specification through the current implementation. The telemetry system provides comprehensive racing data through multiple channels:

Historical (2015): Data written to .ibt files and live API at 60Hz
Current: Enhanced telemetry with sub-tick precision and modern racing features
Session String: YAML format containing session metadata and static information

Appendix A – Telemetry Variables

Data Collection Methods

iRacing's telemetry comes in three variations:

Data written to an .ibt file 60 times a second
Live data exposed to our telemetry API 60 times a second
A session string in YAML format that contains more or less static information about the session

The YAML string is appended to the end of the .ibt file but only a small portion of that data is exposed to ATLAS.

Note: This documentation combines the original 2015 specification with current telemetry variables. Variables marked with NEW are additions since 2015, while variables marked with 2015 are from the original specification. Variables marked with BOTH exist in both versions.

Session and Race Control

Name	Unit	Type	Status	Description
SessionTime	s	double		Seconds since session start
SessionTick		int	NEW	Session tick counter
SessionNum		int		Session number
SessionState		irsdk_SessionState		Session state
SessionUniqueID		int		Session ID
SessionFlags		irsdk_Flags bitfield		Session flags
SessionTimeRemain	s	double		Seconds left till session ends
SessionLapsRemain		int		Laps left till session ends
SessionLapsRemainEx		int	NEW	Extended laps remaining data
SessionTimeTotal	s	double	NEW	Total session time
SessionLapsTotal		int	NEW	Total session laps
SessionJokerLapsRemain		int	NEW	Joker laps remaining
SessionOnJokerLap		bool	NEW	Currently on joker lap
SessionTimeOfDay	s	float	NEW	Time of day in session
RadioTransmitCarIdx		int		The car index of the current person speaking on the radio
RadioTransmitRadioIdx		int		The radio index of the current person speaking on the radio
RadioTransmitFrequencyIdx		int		The frequency index of the current person speaking on the radio
DisplayUnits		int		Default units for the user interface 0 = english 1 = metric
DriverMarker		bool		Driver activated flag
EnterExitReset		int		Indicate action the reset key will take 0 enter 1 exit 2 reset

Push-to-Pass and Boost Systems

Name	Type	Status	Description
PushToPass	bool	NEW	Push-to-pass system activated
ManualBoost	bool	NEW	Manual boost activated
ManualNoBoost	bool	NEW	Manual boost disabled
CarIdxP2P_Status	bool[]	NEW	Push-to-pass status by car index
CarIdxP2P_Count	int[]	NEW	Push-to-pass count by car index

Track and Replay Status

Name	Unit	Type	Description
IsOnTrack		bool	1=Car on track physics running with player in car
IsOnTrackCar		bool	1=Car on track physics running
IsInGarage		bool	1=Car in garage physics running
IsReplayPlaying		bool	0=replay not playing 1=replay playing
ReplayFrameNum		int	Integer replay frame number (60 per second)
ReplayFrameNumEnd		int	Integer replay frame number from end of tape
ReplayPlaySpeed		int	Replay playback speed
ReplayPlaySlowMotion		bool	0=not slow motion 1=replay is in slow motion
ReplaySessionTime	s	double	Seconds since replay session start
ReplaySessionNum		int	Replay session number
IsDiskLoggingEnabled		bool	0=disk based telemetry turned off 1=turned on
IsDiskLoggingActive		bool	0=disk based telemetry file not being written 1=being written

Performance Monitoring

Name	Unit	Type	Status	Description
FrameRate	fps	float		Average frames per second
CpuUsageFG	%	float	NEW	Foreground CPU usage
CpuUsageBG	%	float		Percent of available time bg thread took with a 1 sec avg
GpuUsage	%	float	NEW	GPU usage percentage
MemPageFaultSec		float	NEW	Memory page faults per second
ChanAvgLatency	ms	float	NEW	Channel average latency
ChanLatency	ms	float	NEW	Channel current latency
ChanQuality	%	float	NEW	Channel quality percentage
ChanPartnerQuality	%	float	NEW	Partner channel quality
ChanClockSkew		float	NEW	Channel clock skew

Player Car Data

Name	Unit	Type	Status	Description
PlayerCarIdx		int	NEW	Player car index
PlayerCarPosition		int		Players position in race
PlayerCarClassPosition		int		Players class position in race
PlayerCarClass		int	NEW	Player car class
PlayerTrackSurface		int	NEW	Player track surface type
PlayerTrackSurfaceMaterial		int	NEW	Player track surface material
PlayerCarTeamIncidentCount		int	NEW	Team incident count
PlayerCarMyIncidentCount		int	NEW	Personal incident count
PlayerCarDriverIncidentCount		int	NEW	Driver incident count
PlayerCarWeightPenalty	kg	float	NEW	Weight penalty applied
PlayerCarPowerAdjust	%	float	NEW	Power adjustment percentage
PlayerCarDryTireSetLimit		int	NEW	Dry tire set limit
PlayerCarTowTime	s	float	NEW	Time spent being towed
PlayerCarInPitStall		bool	NEW	Player car in pit stall
PlayerCarPitSvStatus		int	NEW	Pit service status
PlayerTireCompound		int	NEW	Player tire compound
PlayerFastRepairsUsed		int	NEW	Fast repairs used by player

Car Index Arrays (Multi-Car Data)

These variables provide data for all cars in the session (up to 64 entries):

Name	Unit	Type	Status	Description
CarIdxLap		int[]		Lap count by car index
CarIdxLapCompleted		int[]	NEW	Completed laps by car index
CarIdxLapDistPct	%	float[]		Percentage distance around lap by car index
CarIdxTrackSurface		int[]		Track surface type by car index
CarIdxTrackSurfaceMaterial		int[]	NEW	Track surface material by car index
CarIdxOnPitRoad		bool[]		On pit road between the cones by car index
CarIdxPosition		int[]		Cars position in race by car index
CarIdxClassPosition		int[]		Cars class position in race by car index
CarIdxClass		int[]	NEW	Car class by car index
CarIdxF2Time	s	float[]		Race time behind leader or fastest lap time otherwise
CarIdxEstTime	s	float[]		Estimated time to reach current location on track
CarIdxLastLapTime	s	float[]	NEW	Last lap time by car index
CarIdxBestLapTime	s	float[]	NEW	Best lap time by car index
CarIdxBestLapNum		int[]	NEW	Best lap number by car index
CarIdxTireCompound		int[]	NEW	Tire compound by car index
CarIdxQualTireCompound		int[]	NEW	Qualifying tire compound by car index
CarIdxQualTireCompoundLocked		bool[]	NEW	Qualifying tire compound locked
CarIdxFastRepairsUsed		int[]	NEW	Fast repairs used by car index
CarIdxSteer	rad	float[]		Steering wheel angle by car index
CarIdxRPM	revs/min	float[]		Engine rpm by car index
CarIdxGear		int[]		-1=reverse 0=neutral 1..n=current gear by car index

Pace Car and Formation

Name	Type	Status	Description
PaceMode	int	NEW	Current pace mode
CarIdxPaceLine	int[]	NEW	Pace line assignment by car index
CarIdxPaceRow	int[]	NEW	Pace row assignment by car index
CarIdxPaceFlags	int[]	NEW	Pace flags by car index

Vehicle Controls and Input

Name	Unit	Type	Status	Description
SteeringWheelAngle	rad	float		Steering wheel angle
Throttle	%	float		0=off throttle to 1=full throttle
Brake	%	float		0=brake released to 1=max pedal force
Clutch	%	float		0=disengaged to 1=fully engaged
Gear		int		-1=reverse 0=neutral 1..n=current gear
RPM	revs/min	float		Engine rpm
ThrottleRaw	%	float		Raw throttle input 0=off throttle to 1=full throttle
BrakeRaw	%	float		Raw brake input 0=brake released to 1=max pedal force
HandbrakeRaw	%	float	NEW	Raw handbrake input
OnPitRoad		bool		Is the player car on pit road between the cones

Force Feedback and Steering

Name	Unit	Type	Status	Description
SteeringWheelPctTorque	%	float		Force feedback % max torque on steering shaft unsigned
SteeringWheelPctTorqueSign	%	float		Force feedback % max torque on steering shaft signed
SteeringWheelPctTorqueSignStops	%	float		Force feedback % max torque on steering shaft signed stops
SteeringWheelPctDamper	%	float		Force feedback % max damping
SteeringWheelAngleMax	rad	float		Steering wheel max angle
SteeringWheelLimiter		float	NEW	Steering wheel limiter
SteeringWheelTorque	N*m	float		Output torque on steering shaft
SteeringWheelTorque_ST	N*m	float	NEW	Output torque on steering shaft (sub-tick)
SteeringWheelPeakForceNm	N*m	float		Peak torque mapping to direct input units for FFB
SteeringWheelMaxForceNm	N*m	float	NEW	Maximum force in Newton-meters
SteeringWheelUseLinear		bool	NEW	Use linear force feedback

Lap Data and Timing

Name	Unit	Type	Status	Description
Lap		int		Lap count
LapCompleted		int	NEW	Completed lap count
LapDist	m	float		Meters traveled from S/F this lap
LapDistPct	%	float		Percentage distance around lap
RaceLaps		int		Laps completed in race
LapBestLap		int		Players best lap number
LapBestLapTime	s	float		Players best lap time
LapLastLapTime	s	float		Players last lap time
LapCurrentLapTime	s	float		Estimate of players current lap time as shown in F3 box
LapLasNLapSeq		int		Player num consecutive clean laps completed for N average
LapLastNLapTime	s	float		Player last N average lap time
LapBestNLapLap		int		Player last lap in best N average lap time
LapBestNLapTime	s	float		Player best N average lap time

Delta Timing

Name	Unit	Type	Status	Description
LapDeltaToBestLap	s	float		Delta time for best lap
LapDeltaToBestLap_DD	s/s	float		Rate of change of delta time for best lap
LapDeltaToBestLap_OK		bool		Delta time for best lap is valid
LapDeltaToOptimalLap	s	float		Delta time for optimal lap
LapDeltaToOptimalLap_DD	s/s	float		Rate of change of delta time for optimal lap
LapDeltaToOptimalLap_OK		bool		Delta time for optimal lap is valid
LapDeltaToSessionBestLap	s	float		Delta time for session best lap
LapDeltaToSessionBestLap_DD	s/s	float		Rate of change of delta time for session best lap
LapDeltaToSessionBestLap_OK		bool		Delta time for session best lap is valid
LapDeltaToSessionOptimalLap	s	float		Delta time for session optimal lap
LapDeltaToSessionOptimalLap_DD	s/s	float		Rate of change of delta time for session optimal lap
LapDeltaToSessionOptimalLap_OK		bool		Delta time for session optimal lap is valid
LapDeltaToSessionLastlLap	s	float		Delta time for session last lap
LapDeltaToSessionLastlLap_DD	s/s	float		Rate of change of delta time for session last lap
LapDeltaToSessionLastlLap_OK		bool		Delta time for session last lap is valid
LapLastNLapTime	s	float	NEW	Player last N average lap time
LapBestNLapLap		int	NEW	Player last lap in best N average lap time
LapBestNLapTime	s	float	NEW	Player best N average lap time

Delta Timing

Name	Unit	Type	Status	Description
LapDeltaToBestLap	s	float	NEW	Delta time for best lap
LapDeltaToBestLap_DD	s/s	float	NEW	Rate of change of delta time for best lap
LapDeltaToBestLap_OK		bool	NEW	Delta time for best lap is valid
LapDeltaToOptimalLap	s	float	NEW	Delta time for optimal lap
LapDeltaToOptimalLap_DD	s/s	float	NEW	Rate of change of delta time for optimal lap
LapDeltaToOptimalLap_OK		bool	NEW	Delta time for optimal lap is valid
LapDeltaToSessionBestLap	s	float	NEW	Delta time for session best lap
LapDeltaToSessionBestLap_DD	s/s	float	NEW	Rate of change of delta time for session best lap
LapDeltaToSessionBestLap_OK		bool	NEW	Delta time for session best lap is valid
LapDeltaToSessionOptimalLap	s	float	NEW	Delta time for session optimal lap
LapDeltaToSessionOptimalLap_DD	s/s	float	NEW	Rate of change of delta time for session optimal lap
LapDeltaToSessionOptimalLap_OK		bool	NEW	Delta time for session optimal lap is valid
LapDeltaToSessionLastlLap	s	float	NEW	Delta time for session last lap
LapDeltaToSessionLastlLap_DD	s/s	float	NEW	Rate of change of delta time for session last lap
LapDeltaToSessionLastlLap_OK		bool	NEW	Delta time for session last lap is valid

Position and Physics

Name	Unit	Type	Disk	Live	Description
Lat	deg	double	1	1	Latitude in decimal degrees
LatAccel	m/s²	float	1	1	Lateral acceleration (including gravity)
Lon	deg	double	1	1	Longitude in decimal degrees
LongAccel	m/s²	float	1	1	Longitudinal acceleration (including gravity)
Pitch	rad	float	1	1	Pitch orientation
PitchRate	rad/s	float	1	1	Pitch rate
Roll	rad	float	1	1	Roll orientation
RollRate	rad/s	float	1	1	Roll rate
Speed	m/s	float	1	1	GPS vehicle speed
VelocityX	m/s	float	1	1	X velocity
VelocityY	m/s	float	1	1	Y velocity
VelocityZ	m/s	float	1	1	Z velocity
VertAccel	m/s²	float	1	1	Vertical acceleration (including gravity)
Yaw	rad	float	1	1	Yaw orientation
YawNorth	rad	float	1	1	Yaw orientation relative to north
YawRate	rad/s	float	1	1	Yaw rate

Engine and Vehicle Systems

Name	Unit	Type	Disk	Live	Description
ManifoldPress	bar	float	1	1	Engine manifold pressure
OilLevel	l	float	1	1	Engine oil level
OilPress	bar	float	1	1	Engine oil pressure
OilTemp	C	float	1	1	Engine oil temperature
RPM	revs/min	float	1	1	Engine rpm
Throttle	%	float	1	1	0=off throttle to 1=full throttle
ThrottleRaw	%	float	1	1	Raw throttle input 0=off throttle to 1=full throttle
Voltage	V	float	1	1	Engine voltage
WaterLevel	l	float	1	1	Engine coolant level
WaterTemp	C	float	1	1	Engine coolant temp

Pit and Session Data

Name	Unit	Type	Disk	Live	Description
OnPitRoad		bool	1	1	Is the player car on pit road between the cones
PitOptRepairLeft	s	float	1	1	Time left for optional repairs if repairs are active
PitRepairLeft	s	float	1	1	Time left for mandatory pit repairs if repairs are active
PitSvFlags		irsdk_PitSvFlags bitfield	1	1	Bitfield of pit service checkboxes
PitSvFuel	l	float	1	1	Pit service fuel add amount
PitSvLFP	kPa	float	1	1	Pit service left front tire pressure
PitSvLRP	kPa	float	1	1	Pit service left rear tire pressure
PitSvRFP	kPa	float	1	1	Pit service right front tire pressure
PitSvRRP	kPa	float	1	1	Pit service right rear tire pressure
PlayerCarClassPosition		int	1	1	Players class position in race
PlayerCarPosition		int	1	1	Players position in race
RaceLaps		int	0	1	Laps completed in race
SessionFlags		irsdk_Flags bitfield	0	1	Session flags
SessionLapsRemain		int	1	1	Laps left till session ends
SessionNum		int	1	1	Session number
SessionState		irsdk_SessionState int	1	1	Session state
SessionTime	s	double	1	1	Seconds since session start
SessionTimeRemain	s	double	1	1	Seconds left till session ends
SessionUniqueID		int	1	1	Session ID

Steering and Controls

Name	Unit	Type	Disk	Live	Description
SteeringWheelAngle	rad	float	1	1	Steering wheel angle
SteeringWheelAngleMax	rad	float	1	1	Steering wheel max angle
SteeringWheelPctDamper	%	float	1	1	Force feedback % max damping
SteeringWheelPctTorque	%	float	1	1	Force feedback % max torque on steering shaft unsigned
SteeringWheelPctTorqueSign	%	float	1	1	Force feedback % max torque on steering shaft signed
SteeringWheelPctTorqueSignStops	%	float	1	1	Force feedback % max torque on steering shaft signed stops
SteeringWheelPeakForceNm	N*m	float	0	1	Peak torque mapping to direct input units for FFB
SteeringWheelTorque	N*m	float	1	1	Output torque on steering shaft

Weather and Environment

Name	Unit	Type	Disk	Live	Description
RelativeHumidity	%	float	1	1	Relative Humidity
Skies		int	1	1	Skies (0=clear/1=p cloudy/2=m cloudy/3=overcast)
TrackTemp	C	float	1	1	Temperature of track at start/finish line
TrackTempCrew	C	float	1	1	Temperature of track measured by crew around track
WeatherType		int	1	1	Weather type (0=constant 1=dynamic)
WindDir	rad	float	1	1	Wind direction at start/finish line
WindVel	m/s	float	1	1	Wind velocity at start/finish line

Replay and Media

Name	Unit	Type	Live	Description
RadioTransmitCarIdx		int	1	The car index of the current person speaking on the radio
RadioTransmitFrequencyIdx		int	1	The frequency index of the current person speaking on the raio
RadioTransmitRadioIdx		int	1	The radio index of the current person speaking on the radio
ReplayFrameNum		int	1	Integer replay frame number (60 per second)
ReplayFrameNumEnd		int	1	Integer replay frame number from end of tape
ReplayPlaySlowMotion		bool	1	0=not slow motion 1=replay is in slow motion
ReplayPlaySpeed		int	1	Replay playback speed
ReplaySessionNum		int	1	Replay session number
ReplaySessionTime	s	double	1	Seconds since replay session start

Shift Indicators

Name	Unit	Type	Disk	Live	Description
ShiftGrindRPM	RPM	float	1	1	RPM of shifter grinding noise
ShiftIndicatorPct	%	float	1	1	DEPRECATED use DriverCarSLBlinkRPM instead
ShiftPowerPct	%	float	1	1	Friction torque applied to gears when shifting or grinding

Car-Specific Sensors

In addition to the above variables that are always available, there are several variables that only show up if a car implements that particular sensor type.

Suspension Components

Name	Unit	Type	Disk	Live	Description
CFrideHeight	m	float	1	0	CF ride height
CFshockDefl	m	float	1	1	CF shock deflection
CFshockVel	m/s	float	1	1	CF shock velocity
CFSRrideHeight	m	float	1	0	CFSR ride height
CRrideHeight	m	float	1	0	CR ride height
CRshockDefl	m	float	1	1	CR shock deflection
CRshockVel	m/s	float	1	1	CR shock velocity

In-Car Adjustments

Name	Type	Disk	Live	Description
dcABS	float	1	1	In car abs adjustment
dcAntiRollFront	float	1	1	In car front anti roll bar adjustment
dcAntiRollRear	float	1	1	In car rear anti roll bar adjustment
dcBoostLevel	float	1	1	In car boost level adjustment
dcBrakeBias	float	1	1	In car brake bias adjustment
dcDiffEntry	float	1	1	In car diff entry adjustment
dcDiffExit	float	1	1	In car diff exit adjustment
dcDiffMiddle	float	1	1	In car diff middle adjustment
dcEngineBraking	float	1	1	In car engine braking adjustment
dcEnginePower	float	1	1	In car engine power adjustment
dcFuelMixture	float	1	1	In car fuel mixture adjustment
dcRevLimiter	float	1	1	In car rev limiter adjustment
dcThrottleShape	float	1	1	In car throttle shape adjustment
dcTractionControl	float	1	1	In car traction control adjustment
dcTractionControl2	float	1	1	In car traction control 2 adjustment
dcTractionControlToggle	bool	1	1	In car traction control active
dcWeightJackerLeft	float	1	1	In car left weight jacker adjustment
dcWeightJackerRight	float	1	1	In car right weight jacker adjustment
dcWingFront	float	1	1	In car front wing adjustment
dcWingRear	float	1	1	In car rear wing adjustment

Pitstop Adjustments

Name	Type	Disk	Live	Description
dpFNOMKnobSetting	float	1	1	Pitstop front flap adjustment
dpFUFangleIndex	float	1	1	Pitstop front upper flap adjustment
dpFWingAngle	float	1	1	Pitstop front wing adjustment
dpFWingIndex	float	1	1	Pitstop front wing adjustment
dpLrWedgeAdj	float	1	1	Pitstop lr spring offset adjustment
dpPSSetting	float	1	1	Pitstop power steering adjustment
dpQtape	float	1	1	Pitstop qtape adjustment
dpRBarSetting	float	1	1	Pitstop rear bar adjustment
dpRFTruckarmP1Dz	float	1	1	Pitstop rftruckarmP1Dz adjustment
dpRRDamperPerchOffsetm	float	1	1	Pitstop right rear dampter perch offset adjustment
dpRrPerchOffsetm	float	1	1	Pitstop right rear spring offset adjustment
dpRrWedgeAdj	float	1	1	Pitstop rr spring offset adjustment
dpRWingAngle	float	1	1	Pitstop rear wing adjustment
dpRWingIndex	float	1	1	Pitstop rear wing adjustment
dpRWingSetting	float	1	1	Pitstop rear wing adjustment
dpTruckarmP1Dz	float	1	1	Pitstop truckarmP1Dz adjustment
dpWedgeAdj	float	1	1	Pitstop wedge adjustment

Detailed Tire and Suspension Data

Left Front Tire (LF)

Name	Unit	Type	Status	Description
LFcoldPressure	kPa	float		LF tire cold pressure as set in the garage
LFtempCL	C	float		LF tire left carcass temperature
LFtempCM	C	float		LF tire middle carcass temperature
LFtempCR	C	float		LF tire right carcass temperature
LFwearL	%	float		LF tire left percent tread remaining
LFwearM	%	float		LF tire middle percent tread remaining
LFwearR	%	float		LF tire right percent tread remaining
LFshockDefl	m	float		LF shock deflection
LFshockDefl_ST	m	float	NEW	LF shock deflection (sub-tick)
LFshockVel	m/s	float		LF shock velocity
LFshockVel_ST	m/s	float	NEW	LF shock velocity (sub-tick)

Right Front Tire (RF)

Name	Unit	Type	Status	Description
RFcoldPressure	kPa	float		RF tire cold pressure as set in the garage
RFtempCL	C	float		RF tire left carcass temperature
RFtempCM	C	float		RF tire middle carcass temperature
RFtempCR	C	float		RF tire right carcass temperature
RFwearL	%	float		RF tire left percent tread remaining
RFwearM	%	float		RF tire middle percent tread remaining
RFwearR	%	float		RF tire right percent tread remaining
RFshockDefl	m	float		RF shock deflection
RFshockDefl_ST	m	float	NEW	RF shock deflection (sub-tick)
RFshockVel	m/s	float		RF shock velocity
RFshockVel_ST	m/s	float	NEW	RF shock velocity (sub-tick)

Left Rear Tire (LR)

Name	Unit	Type	Status	Description
LRcoldPressure	kPa	float		LR tire cold pressure as set in the garage
LRtempCL	C	float		LR tire left carcass temperature
LRtempCM	C	float		LR tire middle carcass temperature
LRtempCR	C	float		LR tire right carcass temperature
LRwearL	%	float		LR tire left percent tread remaining
LRwearM	%	float		LR tire middle percent tread remaining
LRwearR	%	float		LR tire right percent tread remaining
LRshockDefl	m	float		LR shock deflection
LRshockDefl_ST	m	float	NEW	LR shock deflection (sub-tick)
LRshockVel	m/s	float		LR shock velocity
LRshockVel_ST	m/s	float	NEW	LR shock velocity (sub-tick)

Right Rear Tire (RR)

Name	Unit	Type	Status	Description
RRcoldPressure	kPa	float		RR tire cold pressure as set in the garage
RRtempCL	C	float		RR tire left carcass temperature
RRtempCM	C	float		RR tire middle carcass temperature
RRtempCR	C	float		RR tire right carcass temperature
RRwearL	%	float		RR tire left percent tread remaining
RRwearM	%	float		RR tire middle percent tread remaining
RRwearR	%	float		RR tire right percent tread remaining
RRshockDefl	m	float		RR shock deflection
RRshockDefl_ST	m	float	NEW	RR shock deflection (sub-tick)
RRshockVel	m/s	float		RR shock velocity
RRshockVel_ST	m/s	float	NEW	RR shock velocity (sub-tick)

Legacy 2015 Variables Not in Current TypeScript

The following variables were documented in the 2015 specification but do not appear in the current TypeScript interface. They may have been deprecated, renamed, or are available but not exposed in the TypeScript bindings:

Car-Specific Suspension Components (2015 Only)

Name	Unit	Type	Description
CFrideHeight	m	float	CF ride height
CFshockDefl	m	float	CF shock deflection
CFshockVel	m/s	float	CF shock velocity
CFSRrideHeight	m	float	CFSR ride height
CRrideHeight	m	float	CR ride height
CRshockDefl	m	float	CR shock deflection
CRshockVel	m/s	float	CR shock velocity

In-Car Adjustments (2015 Only)

Name	Type	Description
dcABS	float	In car abs adjustment
dcAntiRollFront	float	In car front anti roll bar adjustment
dcAntiRollRear	float	In car rear anti roll bar adjustment
dcBoostLevel	float	In car boost level adjustment
dcBrakeBias	float	In car brake bias adjustment
dcDiffEntry	float	In car diff entry adjustment
dcDiffExit	float	In car diff exit adjustment
dcDiffMiddle	float	In car diff middle adjustment
dcEngineBraking	float	In car engine braking adjustment
dcEnginePower	float	In car engine power adjustment
dcFuelMixture	float	In car fuel mixture adjustment
dcRevLimiter	float	In car rev limiter adjustment
dcThrottleShape	float	In car throttle shape adjustment
dcTractionControl	float	In car traction control adjustment
dcTractionControl2	float	In car traction control 2 adjustment
dcTractionControlToggle	bool	In car traction control active
dcWeightJackerLeft	float	In car left weight jacker adjustment
dcWeightJackerRight	float	In car right weight jacker adjustment
dcWingFront	float	In car front wing adjustment
dcWingRear	float	In car rear wing adjustment

Extended Pitstop Adjustments (2015 Only)

Name	Type	Description
dpFNOMKnobSetting	float	Pitstop front flap adjustment
dpFUFangleIndex	float	Pitstop front upper flap adjustment
dpFWingAngle	float	Pitstop front wing adjustment
dpFWingIndex	float	Pitstop front wing adjustment
dpLrWedgeAdj	float	Pitstop lr spring offset adjustment
dpPSSetting	float	Pitstop power steering adjustment
dpQtape	float	Pitstop qtape adjustment
dpRBarSetting	float	Pitstop rear bar adjustment
dpRFTruckarmP1Dz	float	Pitstop rftruckarmP1Dz adjustment
dpRRDamperPerchOffsetm	float	Pitstop right rear dampter perch offset adjustment
dpRrPerchOffsetm	float	Pitstop right rear spring offset adjustment
dpRrWedgeAdj	float	Pitstop rr spring offset adjustment
dpRWingAngle	float	Pitstop rear wing adjustment
dpRWingIndex	float	Pitstop rear wing adjustment
dpRWingSetting	float	Pitstop rear wing adjustment
dpTruckarmP1Dz	float	Pitstop truckarmP1Dz adjustment
dpWedgeAdj	float	Pitstop wedge adjustment

Additional 2015 Tire Data

Name	Unit	Type	Description
LFbrakeLinePress	bar	float	LF brake line pressure
LFpressure	kPa	float	LF tire pressure
LFrideHeight	m	float	LF ride height
LFspeed	m/s	float	LF wheel speed
LFtempL	C	float	LF tire left surface temperature
LFtempM	C	float	LF tire middle surface temperature
LFtempR	C	float	LF tire right surface temperature

Similar variables existed for RF, LR, and RR tires in the 2015 documentation. | RFcoldPressure | kPa | float | 1 | 1 | RF tire cold pressure as set in the garage | | RFpressure | kPa | float | 1 | 0 | RF tire pressure | | RFrideHeight | m | float | 1 | 0 | RF ride height | | RFshockDefl | m | float | 1 | 1 | RF shock deflection | | RFshockVel | m/s | float | 1 | 1 | RF shock velocity | | RFspeed | m/s | float | 1 | 1 | RF wheel speed | | RFtempCL | C | float | 1 | 1 | RF tire left carcass temperature | | RFtempCM | C | float | 1 | 1 | RF tire middle carcass temperature | | RFtempCR | C | float | 1 | 1 | RF tire right carcass temperature | | RFtempL | C | float | 1 | 0 | RF tire left surface temperature | | RFtempM | C | float | 1 | 0 | RF tire middle surface temperature | | RFtempR | C | float | 1 | 0 | RF tire right surface temperature | | RFwearL | % | float | 1 | 1 | RF tire left percent tread remaining | | RFwearM | % | float | 1 | 1 | RF tire middle percent tread remaining | | RFwearR | % | float | 1 | 1 | RF tire right percent tread remaining |

Right Rear (RR)

Name	Unit	Type	Disk	Live	Description
RRbrakeLinePress	bar	float	1	1	RR brake line pressure
RRcoldPressure	kPa	float	1	1	RR tire cold pressure as set in the garage
RRpressure	kPa	float	1	0	RR tire pressure
RRrideHeight	m	float	1	0	RR ride height
RRshockDefl	m	float	1	1	RR shock deflection
RRshockVel	m/s	float	1	1	RR shock velocity
RRspeed	m/s	float	1	1	RR wheel speed
RRtempCL	C	float	1	1	RR tire left carcass temperature
RRtempCM	C	float	1	1	RR tire middle carcass temperature
RRtempCR	C	float	1	1	RR tire right carcass temperature
RRtempL	C	float	1	0	RR tire left surface temperature
RRtempM	C	float	1	0	RR tire middle surface temperature
RRtempR	C	float	1	0	RR tire right surface temperature
RRwearL	%	float	1	1	RR tire left percent tread remaining
RRwearM	%	float	1	1	RR tire middle percent tread remaining
RRwearR	%	float	1	1	RR tire right percent tread remaining

Live-Only Array Data

In addition there is a series of variables that are only ever output live (not available in ATLAS) that show up in an array format with one entry for each car in the race, up to 64 entries.

Name	Unit	Type	Live	Description
CarIdxClassPosition		int	1	Cars class position in race by car index
CarIdxEstTime	s	float	1	Estimated time to reach current location on track
CarIdxF2Time	s	float	1	Race time behind leader or fastest lap time otherwise
CarIdxGear		int	1	-1=reverse 0=neutral 1..n=current gear by car index
CarIdxLap		int	1	Lap count by car index
CarIdxLapDistPct	%	float	1	Percentage distance around lap by car index
CarIdxOnPitRoad		bool	1	On pit road between the cones by car index
CarIdxPosition		int	1	Cars position in race by car index
CarIdxRPM	revs/min	float	1	Engine rpm by car index
CarIdxSteer	rad	float	1	Steering wheel angle by car index
CarIdxTrackSurface		irsdk_TrkLoc int	1	Track surface type by car index

Data Types

Each variable has an associated type, the types are as follows:

Data Types

Each variable has an associated type, the types are as follows:

bool – 8 bit int that can be set to 1 (true) or 0 (false)
int – 32 bit signed integer
float – 32 bit signed floating point number
double – 64 bit signed floating point number
bitfield – 32 bit unsigned integer with each bit representing a different state or value

Array Types in Current Implementation

The current TypeScript interface uses array types for all telemetry variables:

bool[] – Array of boolean values
int[] – Array of integer values
float[] – Array of floating point values (covers both float and double from 2015)

Most telemetry variables return single-element arrays, while car index variables (CarIdx*) return arrays with one element per car in the session.

Bitfield Types

Here is a description of each of the 4 bitfield types:

irsdk_EngineWarnings

Flag	Hex Value	Description
irsdk_waterTempWarning	0x0001	Water temperature warning
irsdk_fuelPressureWarning	0x0002	Fuel pressure warning
irsdk_oilPressureWarning	0x0004	Oil pressure warning
irsdk_engineStalled	0x0008	Engine stalled
irsdk_pitSpeedLimiter	0x0010	Pit speed limiter active
irsdk_revLimiterActive	0x0020	Rev limiter active

irsdk_Flags

Flag	Hex Value	Description
irsdk_checkered	0x00000001	Checkered flag
irsdk_white	0x00000002	White flag
irsdk_green	0x00000004	Green flag
irsdk_yellow	0x00000008	Yellow flag
irsdk_red	0x00000010	Red flag
irsdk_blue	0x00000020	Blue flag
irsdk_debris	0x00000040	Debris flag
irsdk_crossed	0x00000080	Crossed flag
irsdk_yellowWaving	0x00000100	Yellow waving flag
irsdk_oneLapToGreen	0x00000200	One lap to green
irsdk_greenHeld	0x00000400	Green held
irsdk_tenToGo	0x00000800	Ten to go
irsdk_fiveToGo	0x00001000	Five to go
irsdk_randomWaving	0x00002000	Random waving
irsdk_caution	0x00004000	Caution
irsdk_cautionWaving	0x00008000	Caution waving
irsdk_black	0x00010000	Black flag
irsdk_disqualify	0x00020000	Disqualify
irsdk_servicible	0x00040000	Servicible
irsdk_furled	0x00080000	Furled
irsdk_repair	0x00100000	Repair
irsdk_startHidden	0x10000000	Start hidden
irsdk_startReady	0x20000000	Start ready
irsdk_startSet	0x40000000	Start set
irsdk_startGo	0x80000000	Start go

irsdk_CameraState

Flag	Hex Value	Description
irsdk_IsSessionScreen	0x0001	Is session screen
irsdk_IsScenicActive	0x0002	Is scenic active
irsdk_CamToolActive	0x0004	Camera tool active
irsdk_UIHidden	0x0008	UI hidden
irsdk_UseAutoShotSelection	0x0010	Use auto shot selection
irsdk_UseTemporaryEdits	0x0020	Use temporary edits
irsdk_UseKeyAcceleration	0x0040	Use key acceleration
irsdk_UseKey10xAcceleration	0x0080	Use key 10x acceleration
irsdk_UseMouseAimMode	0x0100	Use mouse aim mode

irsdk_PitSvFlags

Flag	Hex Value	Description
irsdk_LFTireChange	0x0001	Left front tire change
irsdk_RFTireChange	0x0002	Right front tire change
irsdk_LRTireChange	0x0004	Left rear tire change
irsdk_RRTireChange	0x0008	Right rear tire change
irsdk_FuelFill	0x0010	Fuel fill
irsdk_WindshieldTearoff	0x0020	Windshield tearoff
irsdk_FastRepair	0x0040	Fast repair

Enumerated Types

While the following are not actually bitfields, each value has a specific meaning as outlined in the tables below:

irsdk_TrkLoc

Value	Name	Description
-1	irsdk_NotInWorld	Not in world
0	irsdk_OffTrack	Off track
1	irsdk_InPitStall	In pit stall
2	irsdk_AproachingPits	Approaching pits
3	irsdk_OnTrack	On track

irsdk_SessionState

Value	Name	Description
0	irsdk_StateInvalid	Invalid state
1	irsdk_StateGetInCar	Get in car
2	irsdk_StateWarmup	Warmup
3	irsdk_StateParadeLaps	Parade laps
4	irsdk_StateRacing	Racing
5	irsdk_StateCheckered	Checkered
6	irsdk_StateCoolDown	Cool down

Appendix B – Session String

The session string represents all the details about the current state of iRacing and its current session that don't need to be updated 60 times a second. For the most part this is a static string that does not change, however it is not guaranteed to be static and in fact will change as drivers register for the session and as the race results are posted. The string is formatted using the YAML format, a nested data format like XML but one that is easily read by a human. The key to this format is that indentation matters, and - denotes the start of an array entry.

The ATLAS .ibt importer pulls some data from the session string and makes it available to ATLAS, however to see the vast majority of this information you will need to use one of the various telemetry tools to gain access to the data.

Here is a mockup of a session string with every possible entry filled in and some pseudo code to indicate the format of the data and an indication of what each array represents. The data is indicated using standard printf() notation, %s is a string, %d is an integer, and %0.xf is a floating point number where x represents the number of decimal places to display.

Session String Structure

---
WeekendInfo:
  TrackName: %s
  TrackID: %d
  TrackLength: %0.2f km
  TrackDisplayName: %s
  TrackDisplayShortName: %s
  TrackConfigName: %s
  TrackCity: %s
  TrackCountry: %s
  TrackAltitude: %0.2f m
  TrackLatitude: %0.6f m
  TrackLongitude: %0.6f m
  TrackNorthOffset: %0.4f rad
  TrackNumTurns: %d
  TrackPitSpeedLimit: %0.2f kph
  TrackType: %s
  TrackWeatherType: %s
  TrackSkies: %s
  TrackSurfaceTemp: %0.2f C
  TrackAirTemp: %0.2f C
  TrackAirPressure: %0.2f Hg
  TrackWindVel: %0.2f m/s
  TrackWindDir: %0.2f rad
  TrackRelativeHumidity: %d %
  TrackFogLevel: %d %
  TrackCleanup: %d
  TrackDynamicTrack: %d
  SeriesID: %d
  SeasonID: %d
  SessionID: %d
  SubSessionID: %d
  LeagueID: %d
  Official: %d
  RaceWeek: %d
  EventType: %s
  Category: %s
  SimMode: %s
  TeamRacing: %d
  MinDrivers: %d
  MaxDrivers: %d
  DCRuleSet: %s
  QualifierMustStartRace: %d
  NumCarClasses: %d
  NumCarTypes: %d
  
  WeekendOptions:
    NumStarters: %d
    StartingGrid: %s
    QualifyScoring: %s
    CourseCautions: %s
    StandingStart: %d
    Restarts: %s
    WeatherType: %s
    Skies: %s
    WindDirection: %s
    WindSpeed: %0.2f km/h
    WeatherTemp: %0.2f C
    RelativeHumidity: %d %
    FogLevel: %d %
    Unofficial: %d
    CommercialMode: %s
    NightMode: %d
    IsFixedSetup: %d
    StrictLapsChecking: %s
    HasOpenRegistration: %d
    HardcoreLevel: %d
    
  TelemetryOptions:
    TelemetryDiskFile: "%s"

SessionInfo:
  NumSessions: %d
  Sessions:
    # for each session
    - SessionNum: %d
      SessionLaps: %d
      SessionTime: %0.2f sec
      SessionNumLapsToAvg: %d
      SessionType: %s
      SessionTrackRubberState: %s
      ResultsPositions:
        # for each car in position order
        - Position: %d
          ClassPosition: %d
          CarIdx: %d
          Lap: %d
          Time: %.3f
          FastestLap: %d
          FastestTime: %.3f
          LastTime: %.3f
          LapsLed: %d
          LapsComplete: %d
          LapsDriven: %.3f
          Incidents: %d
          ReasonOutId: %d
          ReasonOutStr: %s
      ResultsFastestLap:
        - CarIdx: %d
          FastestLap: %d
          FastestTime: %.3f
      ResultsAverageLapTime: %.3f
      ResultsNumCautionFlags: %d
      ResultsNumCautionLaps: %d
      ResultsNumLeadChanges: %d
      ResultsLapsComplete: %d
      ResultsOfficial: %d

QualifyResultsInfo:
  Results:
    # for each car
    - Position: %d
      ClassPosition: %d
      CarIdx: %d
      FastestLap: %d
      FastestTime: %.3f

CameraInfo:
  Groups:
    # for each camera group
    - GroupNum: %d
      GroupName: %s
      IsScenic: true
      Cameras:
        # for each camera in group
        - CameraNum: %d
          CameraName: %s

RadioInfo:
  SelectedRadioNum: %d
  Radios:
    # for each radio
    - RadioNum: %d
      HopCount: %d
      NumFrequencies: %d
      TunedToFrequencyNum: %d
      ScanningIsOn: %d
      Frequencies:
        # for each frequency in radio
        - FrequencyNum: %d
          FrequencyName: "%s"
          Priority: %d
          CarIdx: %d
          EntryIdx: %d
          ClubID: %d
          CanScan: %d
          CanSquawk: %d
          Muted: %d
          IsMutable: %d
          IsDeletable: %d

DriverInfo:
  DriverCarIdx: %d
  DriverHeadPosX: %.3f
  DriverHeadPosY: %.3f
  DriverHeadPosZ: %.3f
  DriverCarIdleRPM: %.3f
  DriverCarRedLine: %.3f
  DriverCarFuelKgPerLtr: %.3f
  DriverCarFuelMaxLtr: %.3f
  DriverCarMaxFuelPct: %.3f
  DriverCarSLFirstRPM: %.3f
  DriverCarSLShiftRPM: %.3f
  DriverCarSLLastRPM: %.3f
  DriverCarSLBlinkRPM: %.3f
  DriverPitTrkPct: %.3f
  DriverCarEstLapTime: %.3f
  DriverSetupName: %s
  DriverSetupIsModified: %d
  DriverSetupLoadTypeName: %s
  DriverSetupPassedTech: %d
  Drivers:
    # for each car
    - CarIdx: %d
      UserName: %s
      AbbrevName: %s
      Initials: %s
      UserID: %d
      TeamID: %d
      TeamName: %s
      CarNumber: "%s"
      CarNumberRaw: %d
      CarPath: %s
      CarClassID: %d
      CarID: %d
      CarScreenName: %s
      CarScreenNameShort: %s
      CarClassShortName: %s
      CarClassRelSpeed: %d
      CarClassLicenseLevel: %d
      CarClassMaxFuelPct: %.3f %
      CarClassWeightPenalty: %.3f kg
      CarClassColor: 0x%02x%02x%02x
      IRating: %d
      LicLevel: %d
      LicSubLevel: %d
      LicString: %s
      LicColor: 0x%s
      IsSpectator: %d
      CarDesignStr: %s
      HelmetDesignStr: %s
      SuitDesignStr: %s
      CarNumberDesignStr: %s
      CarSponsor_1: %d
      CarSponsor_2: %d
      ClubName: %s
      DivisionName: %s

SplitTimeInfo:
  Sectors:
    # for each sector
    - SectorNum: %d
      SectorStartPct: %.3f

API Evolution Summary

Key Changes Since 2015

Sub-Tick Data: Addition of _ST suffix variables providing higher precision physics data
Modern Racing Features: Push-to-Pass, tire compounds, enhanced pit strategies
Enhanced Monitoring: Performance metrics, network quality, system resource usage
Improved Tire Management: Comprehensive tire set tracking and compound management
Better Multi-Car Support: Enhanced car index arrays with more detailed information
Pace Car Integration: Full support for formation laps and pace car procedures

Compatibility Notes

Core telemetry variables (throttle, brake, steering, etc.) remain consistent
New variables are additive - existing applications should continue to work
Geographic variables (Lat/Lon/Alt) appear to be deprecated in current implementation
Some car-specific adjustment variables may have been reorganized or deprecated
TypeScript interface provides type safety and better development experience

Recommendations for Developers

Use Current Interface: Leverage the auto-generated TypeScript interface for new development
Sub-Tick Data: Consider using _ST variables for high-precision physics applications
Modern Features: Take advantage of tire compound and P2P systems for strategy applications
Backward Compatibility: Check for variable existence before accessing newer telemetry points
Performance Monitoring: Utilize new performance metrics for optimization and debugging

This documentation combines the original 2015 iRacing telemetry specification with current implementation details from the auto-generated TypeScript interface. Variable availability may vary depending on car type, session configuration, and iRacing version.

teknologika/iRacing Telemetry Documentation.md

Position and Physics

Geographic Data (Legacy - 2015 Only)

Engine and Vehicle Systems

Shift and Power Systems

Weather and Environment

Driver Change and Team Racing

System and Graphics

Pit Services and Repairs

Enhanced Tire Management

Individual Tire Usage Tracking

Tire Set Tracking

Camera System

Tire Rumble Effects

Driver Controls and Adjustments

Pitstop Adjustments

Overview

Appendix A – Telemetry Variables

Data Collection Methods

Session and Race Control

Push-to-Pass and Boost Systems

Track and Replay Status

Performance Monitoring

Player Car Data

Car Index Arrays (Multi-Car Data)

Pace Car and Formation

Vehicle Controls and Input

Force Feedback and Steering

Lap Data and Timing

Delta Timing

Delta Timing

Position and Physics

Engine and Vehicle Systems

Pit and Session Data

Steering and Controls

Weather and Environment

Replay and Media

Shift Indicators

Car-Specific Sensors

Suspension Components

In-Car Adjustments

Pitstop Adjustments

Detailed Tire and Suspension Data

Left Front Tire (LF)

Right Front Tire (RF)

Left Rear Tire (LR)

Right Rear Tire (RR)

Legacy 2015 Variables Not in Current TypeScript

Car-Specific Suspension Components (2015 Only)

In-Car Adjustments (2015 Only)

Extended Pitstop Adjustments (2015 Only)

Additional 2015 Tire Data

Right Rear (RR)

Live-Only Array Data

Data Types

Data Types

Array Types in Current Implementation

Bitfield Types

irsdk_EngineWarnings

irsdk_Flags

irsdk_CameraState

irsdk_PitSvFlags

Enumerated Types

irsdk_TrkLoc

irsdk_SessionState

Appendix B – Session String

Session String Structure

API Evolution Summary

Key Changes Since 2015

Compatibility Notes

Recommendations for Developers