@ syndrome .. 44 mm x 12 mm.
We did some spool building today.
the "old" spool from the first 415 is not gonna fit the new 37 pulley`s
that`s the same problem we had with fitting the wide pitch pulley to the msx
you need the spool axle that comes with the MRE. then the 37 pulley is a perfect fit.
the sleeves don`t fit anymore, because the diff bearing holder is thicker.
you need to shave about 1mm .
sorry for the blurry picture,