it's because the pressure in your tyres expands more-(warm air expands)-especially in summer and the rubber softens fast when its hot also escpecially in the tyre shoulders (doha is full of roundabouts),it's compulsary to change your tyres especially when its wornout to avoid accidents..when your tyre fails,it very difficult to control your vehicle,even at low speeds.so better change it.of corse choose a tyre with TEMP. A rating(high-temp),it's written on the sidewall area.it's the gulf standard for tyres.