WE ARE HEADING TO ST.ANOTHONYS IDAHO IN A FEW WEEKS.WE HAVE 2002 E-TON VIPER 50CC,ANDA 2001 KASEA SKYHAWK 90CC.WE JUST BOUGHT THEM SHREDDER TIRES AND ALL TREKKER TIRES,WE ARENT SURE HOW MUCH AIR SHOULD BE IN THESE TO RIDE IN THE SAND. ANY IDEAS???