The Seiko caliber Seiko 4R34 GMT movement (also known as the 4R34A) is a new and affordable automatic GMT movement used in the Seiko 5 Sports GMT series. The NH34 is the nearly identical version of the movement that is sold to third parties.
The 4R34 features an accuracy of +45 to -35 seconds per day, hand-winding, hacking, a 41-hour power reserve, 24 jewels, 21,600 BPH, and a Diashock antishock system. The 4R34 is used in new Seiko 5 Sports GMTs SSK001, SSK003, and SSK005. When outsourced, the 4R34 is rebranded as the NH34.
Read on to discover the 4R34’s specifications, how it stacks up to other movements, watch case compatibility, and more.
Seiko 4R34 Specifications
| Manufacturer | Seiko |
| Caliber | 4R34 / 4R34A |
| Movement Type | Automatic |
| Diameter | 27.4 mm |
| Casing Diameter | 27 mm |
| Height | 5.32 mm |
| Jewels | 24 |
| Hacking | Yes |
| Hand-Winding | Yes |
| Vibrations Per Hour | 21,600 BPH |
| Shock System | Diashock |
| Regulator | Etachron |
| Power Reserve | ~41 hours |
| Winding Direction | Clockwise |
| Country of Manufacture | Japan |
| Known Watches | Seiko 5 Sports GMT: SBSC001/SSK001, SBSC003/SSK003 and SBSC005/SSK005 |
4R34 Accuracy
The 4R34 has an accuracy of +45 to -35 seconds when worn on the wrist under normal conditions, which Seiko specifies as between 5°C and 35°C.
Setting the Time
To set the time on the 4R34 movement, do the following:
- Pull the crown out two clicks.
- Rotate the crown clockwise to move the time forward and counterclockwise to move it backward. Rotate until the time displayed is correct.
- Push the crown back into place.
Setting the Date
Here’s how to set the date on the 4R34:
- Pull the crown out halfway or one click.
- Rotate the crown counterclockwise until you see the correct date.
- Push the crown back into place.
Note: Do NOT set the date when the watch is set between 9:00 p.m. and 3:00 a.m. as this may damage the date wheel.
Using the GMT to Track Another Time Zone
To use the GMT to track another time zone:
- Pull the crown out halfway (one click).
- Turn the crown clockwise until the GMT hour hand matches the hour of your desired time zone on the watch’s bezel.
- Push the crown into its starting position.
Alternatively, use the GMT bezel to track an additional time zone :
- Turn the bezel until the corresponding time lines up with the 24-hour hand.
I.E., tracking the time zone for London while in the U.S.
If it is currently 8 am in London, turn the bezel until the number 8 on the bezel lines up with the 24-hour GMT hand.
Winding the 4R34
The 4R34 is an automatic movement that also has a manual winding feature. A watch with this movement winds itself through the motion on your wrist, so manual winding is unnecessary.
However, if you wish to hand-wind the 4R34 movement, turn the crown clockwise while it is in position 1, pushed toward the case. Generally, about 40 rotations will fully power the movement, allowing it to run for its approximated 41-hour power reserve. Don’t worry; you can’t overwind this movement.
4R34 vs NH34
The NH34 is an unbranded version of the 4R34 movement that Seiko sells to third parties, such as microbrands.
The 4R34 and the NH34 have identical specifications. The NH34 contains 24 jewels, has a 21,600 BPH, and is manufactured in Japan.
4R34 vs 4R36
The Seiko 4R34 movement is a GMT movement, while the 4R36 is a time-only movement. The 4R36 is a great, cheaper alternative for somebody who would not find the GMT useful, as it is featured in more affordable Seiko watches, such as the Seiko 5 Sports divers.
While both have hacking and hand-winding, the 4R34 only has a date display, while the 4R36 has both day and date displays.
Due to the added complications of the GMT in the 4R34, the few existing watches that use the movement are more expensive than movements that use the 4R36, making it a better choice for those who specifically want a GMT in their watch.
Watches that Use the 4R34
The 4R34 is used in Seiko 5 Sports GMT watches:
- SBSC001/SSK001
- SBSC003/SSK003
- SBSC005/SSK005
We will likely see many microbrands begin to design watches using the NH34 movement shortly.
Is the 4R34 Compatible with Watch Cases That Use the NH35 or 4R15?
Yes, if the NH35 watch case has enough clearance for the additional .4mm of the height of the 4R34, it will fit the movement. The movements are nearly identical and universally compatible otherwise.
The 4R34 is .4 mm taller than the NH35 almost exclusively because of the added GMT hand, and the hand post to support it.
Attempting to use the 4R34 in a case that is too short will result in the handset scratching against the crystal, damaging the crystal and the movement.
4R34 Complications
The 4R34 features three noteworthy complications:
Hacking
Hacking is the ability to stop the second hand when pulling out the crown. This lets you accurately set the second hand and the minute and hour hands to keep time as precise as possible.
Hand-Winding
For those that love the feel of winding their own watch, the 4R34 provides that option. Hand-winding also has practical purposes. It’s easier to fully wind an automatic watch this way rather than shaking it vigorously (which could damage small parts inside).
GMT
A GMT hand and a 24-hour bidirectional rotating bezel allow you to track an additional time zone anywhere in the world, making it the perfect watch for globetrotters.
Seiko 4R34 Manual
If you are having trouble with your 4R34 movement or would like to learn more about it, visit the official manual from Seiko.
Summary
The 4R34 is one of the most affordable automatic GMT movements ever made. It’s a welcome addition to Seiko’s new Seiko 5 Sports GMT watches. It will also be a welcome addition to the workbench of any watch mods or microbrands that take advantage of the identical NH34 variant.
