how do you exactlly determine tread life by %s. what do you exactlly look for?

 

You can look up the original tread depth of the tire in the tire specs, either on the tire manufacturer's website or on the website of a retailer like the Tire Rack. You can then pro-rate any tread depth between the tread depth when new, and the tread depth when you toss it. Many people toss a tire when the treadwear indicator bars are flat across, which happens at 2/32" of tread depth. (Granted, some people throw a tire out before that, if they're worried about wet traction. Others go past 2/32" of tread depth, even though it's illegal to do so on public roads. But you can assume that the tire is used until the bars are flat across at 2/32".)

Let's say a tire has 10/32" of tread depth when new. Then the tire uses up 8/32" of tread depth during its life, until it's at 2/32". When the tread depth goes down to 8/32", it has used 25 percent and still has 75 percent left. When the tread depth is 6/32", it has used 50 percent and still has 50 percent left. When the tread depth is 4/32", it has used 75 percent and still has 25 percent left.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nsxtasy &raquo;</TD></TR><TR><TD CLASS="quote">
Let's say a tire has 10/32" of tread depth when new. Then the tire uses up 8/32" of tread depth during its life, until it's at 2/32". When the tread depth goes down to 8/32", it has used 25 percent and still has 75 percent left. When the tread depth is 6/32", it has used 50 percent and still has 50 percent left. When the tread depth is 4/32", it has used 75 percent and still has 25 percent left.
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There is a tool out there designed specifically to measure tread depth. It's cheap just like an air pressure guage, and can measure to 1/32's inch or in millimeters. You should be able to get one @ your local parts store...If not, try here...

http://www.sjdiscounttools.com/mils-448.html

Hope this helps

Matt

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Neo79Si &raquo;</TD></TR><TR><TD CLASS="quote">There is a tool out there designed specifically to measure tread depth. It's cheap just like an air pressure guage, and can measure to 1/32's inch or in millimeters.</TD></TR></TABLE>

Measuring tread depth is exactly what it sounds like - measuring the distance between the top of the tread blocks and the bottom of the deepest tread grooves. So you can use just about anything to measure, as long as it's accurate.

When I was at Discount Tire recently, they had cards (about the size of a credit card) printed with tread depth measurements along one edge, so you could use one to measure tread depth. They were free.

 

again, good freakin info