They are supposed to be the same, 7mm. I just took a look at both of them, and it sure does look the same. Maybe need to use a more scientific method, like a caliper to measure.
actually they are not that slim. I think it is the same size as Ti 10. Probably because the way yonex designed the ISO TI SP racquet which makes it feels like its shaft is slim. The weight is concentrated on the grip and the head, and feels like there's little weight on the shaft. And this contributes to the SWING SPEED ........................
But MP-100 is thicker right? I measured that MP-100 is 7.5mm while TIS is 7mm... MP100 is too hard to drive because of this I guess...