Aside from running retread snow tires (which are basically worn out after 1 winter season of driving) on some of my early cars, I personally would rather buy less expensive new tires than go with retreads. On bikes, I don't think I'd even consider retreads - they may be safe, but with my luck, I'd get the odd flier that the QC inspector missed. At least on a car/truck, if the retread throws its cap off you get a bumpy ride to the breakdown lane - on a bike - fall down go boom!