Tyre thread design for what size?

[SimonTan]

I have seen the 175 to 235 tyres all uses the same thread design.

The water grooves are same width.

Shouldn't smaller tyres 175 have narrower water grooves, as there is lesser volume of water to push out from the smaller footprint?

 

Sometimes I wonder how the tyres thread are designed for wide or narrow tyres?

 

The reason is same thread design on different sized tyres do give different results. Which is why nowadays, the tyres test must state the tyres size and whether front/rear wheel drive.