[header] How to check tire tread [title] Place a penny into any tread groove on your tire. [title] Rotate the penny so abraham lincoln's head is upside down and inside the tread. [title] Determine whether you can see lincoln's entire head when the penny is inserted into the tread groove. 
[step] Your tires are considered safe and legal if a portion of lincoln's head is covered by the tread. However, if you can see lincoln's entire head after inserting the penny into the groove, you may need to replace your tire.