"If a typical set of cheap tires lasts 50,000 km (30,000 miles) then according to this study they would emit 290 kg (640 lb) of pollution over the life of the tire.  Google says a light car tire weighs 20 lb (9 kg).  There's a conservation of mass issue going on here."

"Checkering looks great. Here's an example showing how to achieve this look in SolidWorks - it takes more work to do checkering in CAD than in real life! http://blogs.solidworks.com/tech/2015/05/solidworks-part-reviewer-checkering-tutorial.html"