AFTER AFEW YEARS THEY TEND TO DRY OUT AND BLOW OUT IF ONE GOES MIGHT AS WELL GET THEM ALL MAY SAVE YOU A STOP SIDE THE ROAD WHERE YOU DON'T WANT TO BE . JUST REPLACED MINE ONE AT A TIME . BUT GOOD TIRES AND PLENTY OF AIR THEY WILL LAST LONGER . GOT ABOUT 7 YEARS OUT OF MINE . SPEND THAT MONEY YOU WON . AIN'T THE WAY IT HAPPENS .