Ahh, I see I see, thx C-Hing, use the 3 Racing part. So does that mean [u]no[/u] bearings needed between the main gear and the shaft? Only use the 賽鋼介子?
Thx C-Hing, I have order the 3 Racing rings (賽鋼介子). But I also made a good discovery to share with C-Hing.
[Stupid me... ] I realise I also bought a steel TRG shaft option for F104 before. It is expensive ($1xx), but as it turns out, it does three things:-
a) steel being stronger
b) the steel extends the "entire length" so the original tamiya "internal" silver aluminium part of the diff assembly is not needed. As such the whole diff structure is a lot stronger (I actually bent the entire diff assembly in a bad crash before >$1xx damage as a whole new diff is required)
c) "This is the nice discovery" . The TRG shaft also gives the option to use 1/12 or Xenon Main gears. The gear portion of the shaft is 1/4in in diameter, and as a result, with a 3/8 x 1/4 bearing, I can fit the Xenon gear straight onto the TRG shaft. See picture.
Hope this is a useful tip/option for others wanting to use Xenon or 1/12 gears (with 3/8 in hole).
I will still need the 3-Racing rings (賽鋼介子) for use with standard F104 shaft and diff.