What's the diff ?

[RCP57]

Originally Posted by Supermario

Not sure if its been mentioned before Reg, I've seen tire guys underground using a tread depth gauge in those cut outs to measure and keep track of tire wear. I think that's the only purpose? or maybe also just a part of the tire making process?

That would be the only reason for it in my mind but I'm no tire guy. Makes sense that it would otherwise be difficult to gauge wear without it on a smooth tire.