Tuner

Graph Tech Ratio Locking Tuners (4+2, PRL-8421)

Graph Tech's locking RATIO tuners in a 4+2 layout, made for Music Man and other 4-and-2 headstocks.

1 guitar checked: 1 likely drop-in.

Illustration, photo coming soon

Where to buy

Part specs

Tuner hole size

10mm

Confirmed

Mounting pattern

Two-pin casing, usable as-is or with the four included InvisoMatch mounting plates, which let the tuners use the existing screw holes on most guitars. Right-handed 4+2 set.

Confirmed

Gear ratio

Not a single ratio by design, RATIO tuners assign a unique gear ratio to each string position (39:1, 24:1, 20:1, 35:1, 20:1, 12:1 low E to high E), per Graph Tech's own spec

Confirmed

Guitars we've checked

1 guitar checked: 1 likely drop-in.

Music Man

John Petrucci Majesty 2022

Likely drop-in

A locking 4+2 set made for Music Man headstocks, so the layout matches this guitar. It needs 10mm holes, the size this guitar's stock Schaller tuners normally use. Pick the included mounting plate that lines up with your existing screw holes and no drilling is needed.

Why we say this

Graph Tech sell the PRL-8421 specifically as a 4+2 locking set for Music Man headstocks, with 10mm peg holes required and InvisoMatch plates included to reuse existing screw holes, per Graph Tech's own product page. A verified buyer review on Graph Tech's site reports installing this set on a Music Man Majesty with an easy install. This guitar ships with Schaller M6 locking tuners, which normally sit in 10mm holes, though Music Man don't publish the hole size.

Help improve this data

Nothing is flagged as an open question here right now. If you have fitted something to this Graph Tech Ratio Locking Tuners (4+2, PRL-8421) that we haven't covered, send it in.