The S45A's roller colour is a perfect match for Lego's "Dark Bluish Gray" colour scheme. I was excited about testing the new wheels using softer durometer materials on the rollers. As the test show, the S45A provides better traction, which is especially good for lighter robots when compared with the standard S55A 'Orange' compound.
I decided to try and demonstrate the difference in the grip between the new 'S45A' and the older 'S55A' Type Roller Compounds. I built the two test rigs with the axles fixed so the wheel couldn't role to preform the demonstration. I used a sheet of 'Melamine' Whiteboard which is as slippery as glass placed at a gradient of 45 Degrees for the Rotacasters to slide down.
As can be seen in the Video above, the S45A out preforms the S55A easily, even when a 55g Lego Boat Weight is added to the two rigs when it comes to grip. On the down side, being softer, the S45A wheels won't ware as well as the S55A type wheels.