I have the OEM 19 Bridgestone Potenza's and was wondering how I can determine the tread wear on them. Is there a specific tool I need or is it done by eye. Do I have to bring it to an tire shop and have them take a look?

 

i know they do sell a special ruler to judge, but i've heard different easier methods like using a quarter or something like that....i forget what specifically but do a yahoo search and you should find something

 

The old rule of thumb I remember is to place a penny in a tread (on edge, head down). If you can see the top of Lincoln's head, you need new tires.

 

^^ jep.

but some people like me like tires when they are semi-bald as they
stick better sometimes. really depends on the tire.

 

Unfortunately tire compounds harden with miles, temperature cycles, ozone etc. Usually they best dry point is somewhere around half worn 6/32".

http://images.google.com/images?hl=e...ch&sa=N&tab=wi

Note the durometer [pictuered in above] is used to measure the hardness of compound......measure brand new , measure periodically.

How could anyone own a car without a ACCURATE pressure and depth gauge?