I'd be wary about those tires. There may be a chance there's a hidden defect. Freebie beware. What make/brand are they?

Here's a TireRack.com link explaining the Uniform Tire Quality Grade (UTQG) rating system.

Richard | Focused 24-7 2002 Focus ZTS...+275,000km and beyond! Ontario Focus Owners Club | SVTOA-Toronto | SVTOA Redline Rendezvous