JG8 vs JG6: specs compared
Updated 05 September 2026.
7.94 mm
JG8 wins on tube outer diameter
On tube outer diameter, JG8 leads: 7.94 mm versus 6 mm.
| Spec | JG8 | JG6 |
|---|---|---|
| Designation | 5/16" (8 mm) OD | 6 mm OD |
| Size / thread | 5/16" (about 7.94 mm) | 6 mm OD tube |
| Fitting form | push-fit collet, imperial | push-fit collet, metric |
| Seals on | single O-ring plus stainless collet grab-ring | single O-ring plus a stainless collet grab-ring |
| Rating / role | John Guest Speedfit rated 16 bar at 1 C, 10 bar at 20 C | John Guest Speedfit metric fittings for 6mm OD tube; tube OD within 0.1mm of nominal |
| Tube OD | 7.94 mm | 6 mm |
Questions and answers
Which has the higher tube outer diameter, JG8 or JG6?
On tube outer diameter, JG8 leads: 7.94 mm versus 6 mm.
How do JG8 and JG6 compare?
On tube outer diameter, JG8 leads: 7.94 mm versus 6 mm.