How to Cheat on Zwift, and What Can Be Done About It by Garmin?

Cheating with incorrect Power and Weight figures in Zwift is a known issue. While we do not condone it, highlighting these methods may push hardware manufacturers to address longstanding vulnerabilities.

Regular Zwift users are familiar with cheating in everyday rides. While high-profile cases, such as Eddy Hoole’s ban from Zwift and subsequent cheating on MyWhoosh, garner attention, cheating in sanctioned Zwift races is more difficult due to equipment standardisation and weigh-ins. However, casual rides remain largely unregulated, leaving room for manipulation (cheating).

The most effective cheats involve artificially boosting power or lowering weight. Other methods, such as reducing gradient difficulty, also exist. Below are three key ways users cheat in Zwift and how Garmin and the industry could mitigate these exploits.

Weight Doping (1)

Entering a lower body weight increases climbing speed.

Some riders consistently maintain high watts per kilogram (w/kg) for long periods—whether they are professionals or simply exploiting weight doping is difficult to verify. All that you see is people flying past you up hills.

Potential Countermeasures

• Trainer-Based Weight Calibration: Future TACX trainers could introduce weight calibration by establishing a baseline weight for the trainer and bike, then measuring additional weight when the rider mounts. An algorithm would calculate the rider’s weight from the pressure applied to the trainer, considering that some weight is distributed to the front wheel.
• Automated Weight Transmission: The system could periodically transmit in-ride weight data to Zwift for validation.
• Performance Analysis: Zwift could analyse riders’ power-duration curves and impose age-related w/kg thresholds. Riders exceeding these thresholds would need to verify, potentially via real-world Strava data which should clearly show they are fast riders and that a high w/kg is plausible.

Some racers lower their weight during the ride before hills; Zwift can stop riders from changing weight in those scenarios.

Power Doping (1) – Trainer Manipulation

Some users exploit incorrect trainer calibration or use additional hardware to alter power data before transmission to Zwift.

Potential Countermeasures

• Data Encryption: Garmin implements encrypted data transmission to comply with EU regulations. Power meters should broadcast encrypted data where possible, which Zwift would decode.
• Power Stream Validation: Zwift should periodically validate power meter data against Bluetooth transmissions and trainer power readings. Users failing to provide consistent data streams could be flagged.
• Multiple Power Source Verification: Like MyWhoosh, Zwift could require a secondary power source for verification.

Power Doping (2) – Pedal Power Meter Manipulation

Power meter pedals allow static weight calibration, where users can enter a scale factor to adjust accuracy. Some brands, including Garmin Rally and Favero Assioma, allow such adjustments, potentially inflating power readings by up to 10%.

Potential Countermeasures

• Adjustment Limits: Manufacturers could restrict adjustments to a 3-5% range.
• Adjustment Transparency: Any modifications should be transmitted within the power data stream and flagged in the Zwift interface.

Power Doping (3) – Crank Length Manipulation

Power meters designed for interchangeable use require manual crank length entry. Entering a shorter crank length than the actual measurement artificially inflates power output.

Potential Countermeasures

• Data Transparency: Crank length settings should be included in transmitted data streams and displayed in Zwift.
• Power Source Cross-Validation: Zwift could flag users using power meter pedals for power data while relying on a smart trainer for resistance and gradient simulation. Why isn’t it being used if a trainer’s power meter is available?

The Way Forward

This site calls for Zwift to introduce ‘Verified Rider’ status with a checkmark always shown next to those riders’ names.

Weight and power doping undermine fair competition in Zwift. By implementing hardware-based calibrations, encrypted data transmission, and stricter software validation, Garmin and Zwift could significantly reduce these exploits. Greater transparency and real-time power verification would deter casual cheating and preserve fairness for all riders.