It almost seems like they "sprout" in the tread grooves, well before the tire is completely worn down to the level of the top of the wear-bars? So you can picture what I mean - if the tread depth is 1/4", the bars are about 1/8" below that, still inside the groove. My guess is that they "measure" 2-3/32" in tread height?

I seem to remember they were not visible at all when the tires were OEM new. Am I correct to suppose that a tire is not all used up just because the bars are now visible? How do the bars know when to show up?

Tatt

 

Wear bars don't sprout. They were always there but were hard to see since the actual tread was so much above the wear bands.

IIRC legal tread is 3/32" which is about the distance from the top of Washington's head to the edge of a quarter. Therefore, if you put a quarter head down into the tread of a tire, if you can see the top of Washington's head, your tires are no longer legal. I haven't checked, but I assume that when the wear bars are flush with the tread, you have about 3/32" of tread left and should be thinking about replacements.

 

The wear bars are always there, molded in the rubber. They don't pop up. Find a new tire, and use the tip of a pen, you will feel them. And yes, the bars are typically 2/32". In states with inspection, 2/32" is the cut off for tires passing.

New tire tread depth is usually 10 or 11/32", so if you still have 1/4" (8/32") you still have lots of life left.

Steve

 

Kewl we at least have the same assumption there. One more assenting vote and I'll have a consensus. I was motivated to find this out when I got a "recommendation" (from someone who sells tires, of course) to replace tires and to me it didn't seem quite like it was time yet (wear-bars not flush with the tread, like you said).

Thing is, it's Mrs. Tatt's Kid-Taxi we're talking about, and I sure don't want to put anyone at unnecessary risk running on blecchy tires .

Thanks,
Tatt

 

The wear bars use the tire pressure sensor circuit to connect to your cell phone and place a call to your bank to check your balance then they show up when you have a little extra money that you had plans for.

 

I knew it was all a conspiracy:impatient

 

OK got it! And to think, I thought all my cell phone was good for was unlocking the car over vast distances.

Since I so rarely have that little bit extra cash, I think my tires might be immortal.

Thanks all, that was very quick,
Tatt

 

Glad I could clear that up.

Seriously now, wear bars are an indicator that the tread is gone, so for sure time to replace, however tires can be done before the wear bars are flush. If they are unevenly worn they will handle poorly with tread left or if they are old and dry they will have less traction even if tread is left. So keeping an eye on tire wear and condition is important.