The OnTrack Internal TPMS Sensors provide live tyre pressure and temperature monitoring for serious track day drivers, racing professionals and performance-focused BMW and Porsche owners. Designed to replace factory valve-stem TPMS units, the system gives drivers accurate real-time data while retaining a clean internal installation. Unlike standard TPMS systems that trigger alerts around OEM road pressures, OnTrack allows custom baseline pressure thresholds to be set through the app. This is especially useful for cars running lower track pressures, semi-slick tyres or second wheel sets, helping avoid unnecessary warnings while still giving meaningful tyre data during use. With an approximate 4-second refresh rate, the sensors deliver live pressure and temperature data directly to the OnTrack iOS app. This turns the system into a genuine performance tool, helping drivers monitor hot pressures, identify temperature changes and make more informed setup decisions during track sessions. The sensors are designed for motorsport environments, with rugged wireless hardware built to withstand the demands of racing and high-speed use. They are compatible with most modern BMW and Porsche vehicles using 433MHz TPMS, making them ideal for dedicated track setups, modified cars and additional wheel packages. The package includes 4 internal wireless tyre pressure and temperature sensors and access to the free OnTrack iOS app download. Some vehicles may require coding to remove factory sensor warnings, depending on the setup. Further information below.