Tires: Sidewall flat, tire industry, drivers ed

Question
Barry,
Were does the sidewall start and the last ribbed tread end is there a diagram I can look at.

Answer
Renee,

I suspect what you are really asking is what part of the tire is repairable.  Many folks think it is the tread - and not the sidewall.

Well, the sidewall is not repairable, but there are parts of the tread that aren't repairable as well.  

In words, the repairable area is the tread EXCLUDING the outermost rib.

Here's a link to a web site that has a picture of the repairable area.  You have to go to the 2nd page to see it.

http://www.conti-online.com/generator/www/us/en/continental/automobile/themes/co...

Even though this is on one particular tire company's web site - the picture is from the tire industry standard repair manual and applies to all brands.