Sur Ron Upgrades

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ERT has been developing upgrades for the Sur Ron Electric bike.

The Sur Ron is a solid platform to build upon, and has huge potential for performance enhancements.


ASI BAC4000 Controller Plug and Play Upgrade with TFT Color Display


This is the first significant performance upgrade that you should consider for your Sur Ron.




  1.            Easy
  • Plug and Play and Easy to Install 
  • Plugs into the OEM harness and connectors, everything bolts on for a true play and plug install.
  • Keeps Original Throttle
  • Controller mounting bracket, bolts onto frame without modifications
  • Eco / Sport mode selector is now at: 2500W / 6000W respectively
  • Retains factory functions (Key Switch, lighting, USB charger, etc)


  • FOC (Field Oriented Control) for smooth throttle control and response, high efficiency,
  • Regenative braking that is variable using a second throttle for precise regen braking control, saves significantly on brake pad wear, and increases range by converting braking force and sending energy back into the battery.
  • Much more aggressive power, higher peak motor current compared to stock Sur Ron, improved starting torque and acceleration.
  • Higher top speed due to field weakening. Original controller would slow down nearing top speed, where as Field Weakening allows the motor to gain additional 1000rpm. 
  • Controller operates in Hybrid mode (Uses hall sensors for smooth starting, then transitions to sensorless, increasing efficiency and gain in top speed)
  • Sensorless fallback mode in case the hall sensors were to fail
  • Can fully utilize regen (Sur Ron BMS will cut at full charge, however ERT has found a solution for this by limiting regen power at full charge and gradually increasing then restoring full regen power at battery % reaches 95%.
  • Controller is highly water resistant as is the high quality harness that has been designed in house by ERT to be reliable under all terrain environments.
  • Controller has automatic thermal rollback protection for the controller and the motor. 
  • Motor RPM has increased from 5500rpm to 7000rpm.

                 Color Display

  • Color TFT Display is avaliable, with additional 3 mode power selection. Speedometer, ODO, Voltage, Wattage, Clock, etc

                Future Proof

  • Usable up to 92V 463A when battery upgrades are available 

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