What are the many little circles in the tread?

[wbwanzer]

Are these little circles part of the manufacturing process? Or is it part of the tread design? Can't imaging. They don't look very deep.
Is this a Capriracer question?

BTW, it is the Vredestein HiTrac.

I'm liking these as a next tire. Thanks for any input.

 

[jhellwig]

From the curing process.

 

[vavavroom]

Suction cuplets!

 

[wbwanzer]

Suction cuplets!

That's what I was hoping.

 

[CapriRacer]

Are these little circles part of the manufacturing process? Or is it part of the tread design? Can't imaging. They don't look very deep.
Is this a Capriracer question?

BTW, it is the Vredestein HiTrac.

I'm liking these as a next tire. Thanks for any input.

Yes, this is a CapriRacer question!

Those are the tops of a poppet valve that allows air to bleed out between the tire and the mold. In the old days, they used drilled holes, but those had to be trimmed. Another way to do this is to make the mold out of a slightly porous material, but that has problems of its own.