Seiko NH34 vs Miyota 9075: Which is the Better GMT Movement

We’ve sung the praises of the NH34 since its release, talking about how it sparked a new frenzy among watch modders as GMT has been a long-awaited complication. There’s a lot of good things going for it, but it’s not the only choice in the market. Seiko modding has always been about having options and customizing a watch to your exact preferences - while the NH34 is sufficient for most GMT builds, what do you use if you want something more premium? You will want to check out the Miyota 9075.

Both the Seiko NH34 and the Miyota 9075 will let you track time in different parts of the world, but they each bring their own strengths to the workbench. Whether you're building your first GMT mod or looking to understand the differences between these movements, this comparison will hopefully help you make an informed decision for your next project.

 

Overview of Each Movement

Seiko NH34

Source: TMI

 

Seiko released the beautiful SSK trio, and the NH34 alongside it, answering the prayers of many from the modding community. Built on the reliable foundations of the NH35 architecture, it beats at a steady 21,600vph and offers a power reserve of approximately 41 hours - and this while basically keeping the same measurements as its brothers in the NH line. For modders, the NH34 typically comes in at around $75-100, making it one of the more affordable but functional GMT options available from any watch brand.

Miyota 9075

Source: Watch-Movements.eu

The Miyota 9075 comes from Citizen's movement manufacturing division and represents a step up in their offering. Operating at a higher 28,800vph, this movement delivers a smoother sweep of the seconds hand compared to the NH34. It has a slightly higher power reserve of around 42 hours and is positioned as a premium option in the market. Pricing typically ranges from $150-200, placing it in a higher bracket than the NH34. The 9075 is part of Miyota's 9000 series, which has earned a reputation for being their high-beat premium movement line, competing more directly with Swiss offerings.

 

Key Comparisons

Modding Compatibility

The NH34 follows Seiko's well-established design language, making it a natural choice for those already familiar with NH35 mods. It accepts standard Seiko-compatible dials with only a slight modification to the center hole, and hands designed for NH35/36 movements will fit perfectly. The GMT hand installation follows similar principles to standard hand-setting, though it requires extra care due to its additional hand height clearance requirements.

The Miyota 9075, however, presents some unique challenges. While the movement itself is excellent, it uses different hand sizes compared to Seiko standards. This means you'll need to source Miyota-specific hands, which can be more difficult to find in the modding market. Moreover, there are very few cases that take advantage of the much slimmer profile of the 9075. Sure, you can make it work with NH-compatible cases by 3D printing your own custom spacer (sounds laborious, we know), but then you have a lot of unutilized space inside your watch.

Performance

In daily use, the NH34 typically delivers accuracy within -20/+40 seconds per day, which is respectable for its price point. The movement winds smoothly, though you might notice a slight graininess typical of Seiko's affordable movements. The GMT function operates with satisfying feedback, and the date changeover is reliably crisp.

Source: @sensationaldadbod on IG

 

The Miyota 9075 generally offers better accuracy, usually within -10/+30 seconds per day. Its higher beat rate results in a noticeably smoother seconds hand sweep. However, the 9075 is known for its signature "rotor noise" – a spinning sound when the watch moves that some users find distracting and others find charming. The GMT setting is precise and the overall operation feels more refined than the NH34.

 

Other Considerations

Durability and Reliability

Both movements have proven themselves reliable, but they show their character in different ways. The NH34 is built to be a daily driver; it's not the most refined, but it can take a beating and keep running just fine. Common issues include slightly inconsistent accuracy over time and occasional date alignment quirks, but these are generally minor concerns.

The Miyota 9075 demonstrates excellent overall reliability, with fewer reported issues regarding date alignment or accuracy drift. However, its more sophisticated construction means that when problems do occur, they can be more complex to solve. The bidirectional winding system is particularly well-engineered, though some users report that the rotor can feel loose compared to the NH34's more solid feel.

Parts Availability

This is where the NH34 truly outshines the competition. Thanks to Seiko's dominant position in the market, parts are readily available from numerous suppliers worldwide. The movement itself is easily purchasable from established watch parts dealers, modding suppliers, and even major online marketplaces at reasonable prices (you can get one from us here). Whether you need replacement stems, crowns, or even rotors, these parts are easy to source and relatively affordable. Most local watchmakers are also familiar with Seiko movements, making repairs straightforward.

 

Getting your hands on a Miyota 9075 can be tricky, especially compared to the NH34. It's not as easily available, and you might need to go straight to Citizen to order one – which isn’t exactly the easiest process for individual modders. Your best bet might be searching eBay or watch modding forums, but availability is hit-or-miss and prices can be unpredictable. 

 

Verdict

After diving deep into both movements, it's clear that the choice between the NH34 and Miyota 9075 depends largely on your specific needs and experience level. Here's how to make your choice:

Choose the Seiko NH34 if you're:

• New to watch modding and want an easier entry point

• Working with a tighter budget

• Planning to use standard Seiko mod parts

• More concerned with parts availability than “the best money can buy”

• Looking for the most straightforward servicing options down the road

Go for the Miyota 9075 if you're:

• An experienced modder looking for a premium movement

• Willing to invest more in your project

• Prioritizing smoother second-hand sweep and slightly better accuracy

• Comfortable working with more specialized parts

• Planning a high-end build where movement refinement is crucial

The 9075's superior technical specifications make it the better choice for premium builds where budget isn't the primary concern. However, be prepared for a more challenging modding experience and potentially higher maintenance costs.

 

Wrap Up

For most modders, the NH34 is the go-to choice and for good reason. It’s accessible, reliable, and fits seamlessly into the Seiko modding ecosystem. But the Miyota 9075 is a reminder that it’s not the only option out there. As the modding scene continues to evolve, who knows? This year might just bring us better access to premium movements like the 9075. Until then, the NH34 remains the hero of GMT builds.

 

Planning an NH34 build of your own? Go premium and check out our catalog of compatible parts in this collection. If you're more interested in Miyota Mods instead, we do have parts for the 90S5 and 9015 calibers which you can check here.

Happy modding!