GR Technologies 65FD vs GR Technologies G66FD Radtke
The GR Technologies G66FD Radtke has a wider cup diameter.
Mouthpiece A
GR Technologies 65FD
• Flugelhorn
Cup diameter16.50 mm / 0.6496 in
Cup depthDeep
Rim width—
Throat diameter—
Backbore—
Finish—
Material—
vs
Mouthpiece B
GR Technologies G66FD Radtke
• Flugelhorn
Cup diameter16.76 mm / 0.6598 in
Cup depthDeep
Rim width—
Throat diameter—
Backbore—
Finish—
Material—
Cup Diameter
The GR Technologies G66FD Radtke has a cup diameter of 16.76 mm / 0.6598 in compared to 16.50 mm / 0.6496 in on the GR Technologies 65FD — a difference of 0.26 mm / 0.0102 in. A wider cup generally produces a fuller, darker tone but requires more air support.
Cup Depth
Both mouthpieces share a deep cup depth, so the sound character from depth alone will be very similar.
Which is better?
Neither mouthpiece clearly dominates the other — the right choice depends on your embouchure, playing style, and the sound you're after. Try both if possible.