Niken tire replacement depth?

[maximNikenGT]

Was checking tread depth on my car tires with a Steelman tread depth tester and was good all around. Depth tester is green if you have >6mm, 3< yellow < 6, and red if <3mm for auto tires. 

Just for fun I decided to test my Niken tires and all three tires showed in yellow / borderline red for replacement on the depth tester. Fronts showed 4 mm of depth while rear tire showed 3mm depth remaining.

I happened to have a brand new set of front replacement Pirelli Diablo Rossi tires and those showed 6mm deep tread remaining. 

So what should the actual tread depth (in mm) be for motorcycle tires before  one  needs replacing? 

 

Edited April 5, 2023 by maximNikenGT
Added photo

[betoney]

The tread depth wear indicators are molded into the tire tread. 
 

I usually replace tires based on degraded handling, (flat or out of round profile) before running them to the wear bars.  I can’t say that I have ever measured tread depth. 

[maximNikenGT]

Ran across this on the Bridgestone site where US tires must have minimum 2/32 in (~1.6mm) depth. Obviously  one should replace them sooner if the tire doesn't feel safe to ride on. 

 

[Gordie]

On 4/4/2023 at 3:49 PM, betoney said:

The tread depth wear indicators are molded into the tire tread. 
 

I usually replace tires based on degraded handling, (flat or out of round profile) before running them to the wear bars.  I can’t say that I have ever measured tread depth. 

I agree with this theory if the tires show signs of being misshapen flat or out of round profile its time to replace them. That will most likely happen before the tread wears out.