Watch Bezel Types Explained: Dive, GMT, and Tachymeter
What Is a Watch Bezel?
The watch bezel is the ring that surrounds the crystal. It sits on top of the case and can be fixed (stationary) or rotating. Different bezel types serve different purposes — from timing dives to tracking a second time zone.
At Funny Items, our watch cases come with different bezel styles depending on the watch type. Here is what each one does.
3 Main Bezel Types
1. Dive Bezel (Unidirectional)
A dive bezel rotates only counterclockwise. It has minute markings from 0-60. You align the zero marker with the minute hand, and as time passes, the minute hand moves past the bezel numbers, showing elapsed time.
Why unidirectional? If the bezel accidentally rotates, it can only show more elapsed time — never less. This is a safety feature for divers who need to know they have enough air.
See: Black Sub NH35 With Date, Vintage Bronze Watch
2. GMT Bezel (Bidirectional)
A GMT bezel rotates both directions and has a 24-hour scale. It works with the GMT hand (4th hand) to track a second time zone. You can rotate the bezel to adjust for different time zones without changing the watch settings.
See: Pepsi NH34 GMT, Batman NH34 GMT, 40mm Bidirection GMT Case
3. Tachymeter Bezel (Fixed)
A tachymeter bezel is fixed (does not rotate). It has a scale used to measure speed over a known distance. Start the chronograph at the beginning of a mile/km, stop it at the end, and the bezel number shows your average speed.
See: 40mm VK Movement Case — chronograph case with tachymeter bezel
Bezel Materials
| Material | Look | Durability | Cost |
|---|---|---|---|
| Ceramic | Glossy, rich color | Excellent — scratch-proof | Higher |
| Aluminum | Matte, lightweight | Good — can scratch | Affordable |
| Stainless steel | Polished or brushed | Excellent | Moderate |
| Bronze | Develops patina | Good — ages with wear | Moderate |
Bezel Insert vs Bezel
These two terms are often confused:
- Bezel — The entire ring assembly on the case, including the insert
- Bezel insert — The flat ring with numbers/markings that sits inside the bezel. This is the part you can replace to change the look of your watch.
A ceramic bezel insert is the most popular upgrade for Seiko mod builds. It is scratch-proof and available in many colors.
How to Replace a Bezel Insert
- Use a thin blade or bezel removal tool to pry off the old insert
- Clean the bezel surface
- Apply the new insert with adhesive (usually included)
- Press firmly to ensure a secure fit
Funny Items offers replacement bezel inserts in ceramic and aluminum for popular case sizes.
Frequently Asked Questions
Can I change the bezel on my watch?
Yes. Most Funny Items cases accept standard bezel inserts. Measure the inner diameter to find the right size.
Ceramic or aluminum bezel?
Ceramic is more scratch-resistant but costs more. Aluminum is lighter and more affordable. Both look great.