On 12/03/2016 03:49, DaveC wrote:
Jasen Betts asked wisely:

do they have the same capstan diameter?

I was just about to say €œSilly question!€� but instead thought better...

one 2mm, one 2.2mm

I guess the difference is driven (c; by the fact (stated by Phil) that the
flywheels are different diameters to discourage mechanical resonance.

Thanks Jasen!

May seem pedantic , but there is a rationale.
Having been here before, to standardise to using a strobe to set tape
speed, in the absence of a test tape of known goodness, ie not
stretched, as the people wanting cassette players repaired these days
tend to be musically on the ball as regards being perfect pitch.
You'll probably find the spindle diameters are 1.99mm and 2.19mm .
I got a precision mechanical engineer to measure a dozen or more random
spindles and they were all *.*9 mm , presumably because the available
bearings are *.*0 mm