Square's website explain it, but I cannot translate Japanese. My english sucks, hard for me to explain.
I don't trust Square's rear Ti input shaft because they did not do good job for SD.
raving-monkey, Order oversea.
This is the translation from Excite. Kinda weird, but....
an input shaft and a SUPA gear -- a hub -- unification GATA is lost and a rotation loss is reduced.