A pneumatic tire comprises a sidewall, an annular tire cavity, and a hydraulic actuator connected to the sidewall inside the annular tire cavity, wherein the hydraulic actuator has a flexible reservoir for containing a hydraulic fluid, and an opening allowing hydraulic fluid to enter the reservoir and to exit the reservoir. Further, the hydraulic actuator comprises a lever arm connected to the sidewall and holding the flexible reservoir between the lever arm and the sidewall, wherein the lever arm comprises a fluid channel allowing hydraulic fluid to flow from the reservoir through the opening out of the lever arm.