from John: 1st – reference: Post-16688
1 The shallow depth of the NSR crown teeth, presses the motor shaft disproportionately against the Thin (0.50mm) “guard-flange” of the Centering Channel.
2 With the Aluminum shank crowns, the guard-flange wears quickly, shedding AL dust and distorting the shape of the Centering Channel.
3 After less than an hour (on a rolling-road) the crown’s mesh has changed (the teeth are alternatively pressing harder/loser against the pinion). Friction increases noticeably.
4 The NSR brand Brass/Bronze shank crowns take over 45 minutes before they start shedding from wear on the guard-rails. The NSR Brass/Bronze crowns also have a (0.50mm) guard-flange.
5 The Slot.IT brand Brass/Bronze shank crowns have a (0.75mm) guard-flange. After 30 minutes on the rolling-road, the Slot.IT Brass/Bronze crowns seem to have little shed, and NOT degrade in mesh/lash (and hence performance.) The slight eccentricity from the Slot.IT having a larger diameter hole 2.38mm (2.998/32 inch, 0.09370in) vs. 2.37mm (2.9858/32 inch, 0.09331in) for the NSR axle, does Not seem to have any obvious consequences.
6 Russ’ solution to use the OEM brass spacers, and Trim the shaft so that it no longer contacts the Centering Channel – seems to be an easy and viable solution.
from Mark:
The wear issue appears to be either a flaw in the Design of the Crown’s teeth (too shallow) or in the Manufacturing during alignment on the Shank (computer parameters mouning the crown on the shank too close to the centering-channel). The skinny 0.50mm Guard-Band also seems like a Doofus design choice with no apparent cost/weight/performance benefit. Note that most NSRs are either short-can pseudo-sidewinders (2deg AW) or long-can angle-winders; so their overall experience with Inlines seems limited (e.g. only ocurrent models with ILs are Mosler, Clio, Abarth, LMP, F1)
In conclusion – I join John in (a) requesting that both (a) the Slot.IT crowns (b) and trimming the motor shaft be Permitted.
"... get on your bad motor scooter and ride!"
Sammy with Montrose