I've wore out three sets of M/T ET Street tires on mu Duster so far, two sets of new tires and one set of used tires, the new ones didn't need any special prep to make them keep air in them The one used set wouldn't hold air worth a crap until I followed what was recommended on here for sealing them, use Dawn dish washing soap straight out of the bottle and coat the intire inside of the tires, let them sit over night to soak in before remounting and reinflating them Works good, last a long time