A tire valve unit includes a tire valve and a sensor unit. The tire valve includes a valve stem and a rubber body located on the periphery of the valve stem. The sensor unit includes a sensor mounted on a wheel and a housing that accommodates the sensor and is secured to the tire valve. The tire valve unit is mounted on the wheel by press-fitting the tire valve into a mounting hole in the wheel. The body includes an attaching portion. The tire valve includes an attaching projection that projects in the axial direction of the tire valve from the inside of the attaching portion toward the outside. The tire valve unit further includes a fixture that secures the attaching projection to the housing.

A bicycle tire pressure cap, used with a bicycle tire valve, comprising a metal case, an anti-leak washer, a ventilation disc, a rubber gasket, a floating holder, a warning plug, a spring and a transparent cover. The bicycle tire pressure has a simple structure, low failure rate, low cost, and can quickly indicate whether the tire pressure is sufficient and effectively enhance the riding safety.

A tire valve unit includes a tire valve and a sensor unit. The tire valve includes a valve stem and a rubber body located on the periphery of the valve stem. The sensor unit includes a sensor mounted on a wheel and a housing that accommodates the sensor and is secured to the tire valve. The tire valve unit is mounted on the wheel by press-fitting the tire valve into a mounting hole in the wheel. The body includes an attaching portion. The tire valve includes an attaching projection that projects in the axial direction of the tire valve from the inside of the attaching portion toward the outside. The tire valve unit further includes a fixture that secures the attaching projection to the housing.