Originally Posted by DiasDePlaya
So why most tires have almost the same treads design for the front and the rear?
By far the main function of the tire tread is to evacuate water.
I think you'll find most of them are opposite. The fronts will V to the rear and the rears will V to the front. The rears drive the bike forward and the fronts get driven to stop.
I would tend to agree that running the V forward on the front could lend to hydroplaning. So you're right in that aspect. If you run a rear in the front in the direction indicated for a rear installation, you get the V facing forward. You want it facing back to channel water and for breaking grip. Hence running them in reverse rotation. I also think this is important for best breaking power on dirt.
My scorpion trails are opposite, front to rears. Sipes in a V facing back to the outside, but the rears have the V facing forward to the outside for best grip when accellerating.