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Tools · 28 March 2008, 10:28 AM

The Tachymeter or Tachometer bezel on your Chronograph is a simple calculator for determining approximate speed in MPH/KPH, or determining a simple rate of production.

For speed estimates, you need a measured mile or kilometer. As the object you want to time enters one point on the measure (milepost) start the stopwatch function of your chronograph. When it reaches the next milepost, stop the second hand. An estimate of mph is read off the bezel.

Here is an example. The time to travel the measured mile took 20.2 seconds or ~179 mph

SpeedyTachy-1.jpg

Rate of production can also be determined. If you are watching an assembly line, or timing an event (say chugging a bottle of water), you start the timer at the beginning of the event. You stop after the end of the event, or when another product comes off the assembly line.

Using our example above; if 1 widget was made during the 20 seconds timed, then 179 widgets are being produced per hour. Or you are chugging a bottle of water at the rate of 179 bottles per hour.

There are more than one type of bezel or scale available for a chronograph. Some are marked with a Telemeter bezel. In the case of our next example below, it is the red scale. When a visual cue at a distance is observed, the timer is started. The timer is stopped when an audible cue that corresponds to the observation is heard. The approximate distance is read off the scale.

Using our example below let's say that a lightning strike is observed, and then the event is timed until the thunderclap is heard. In this case, ~36 seconds, and our scale is calibrated in kilometers, so reading off the telemeter scale, distance is slightly over 12 kilometers away.

In a military application, you can see the flash of the artillary, time the event until you hear the sound, and be able to know the approximate distance away the artillary is placed.

LancoTachy-1.jpg

One last type of bezel encountered is the decimal bezel. This is easily identified because it is calibrated from 1 to 100, Using this bezel, time is read off the bezel in tenths, or hundreds of a minute.. If you time an event and the second hand is stopped at exactly 30 seconds, the decimal bezel would reflect .50 of a minute.

juneja · 28 March 2008, 11:06 AM

My first Omega arrived today, and your timely post (ahem) now enables me to use her properly.

Thank you!!

Wasatch · 28 March 2008, 01:54 PM

Excellent post, Larry. Thank you.

Gurmot · 27 July 2008, 03:47 AM

Another great article, and very useful too but aren't we forgetting another member of the Speedy bezel family?

Here's my 1967 cal 321 Speedy with a Pulsations or Doctor's bezel. It is used to measure heart-rate by recording the time it takes for 15 heart-beats. The watch is stopped after the 15th beat and the equivalent BPM is displayed.

What do you reckon to this one?

Cheers - Simon

yujinyboy · 28 August 2008, 11:29 AM

nice information!

Tools · 28 August 2008, 12:17 PM

Omega also produced a Decimal bezel for the Speedy as shown in this 1970 example.

This bezel was handy if you were interested in knowing hundredths of a minute..

For example; 15 seconds would be 25 hundredths of a minute, or in the case of this photo, the second hand is stopped at 22 seconds, which equals 37 hundredths of a minute.

Speedy Decimal.jpg

jmsrolls · 11 October 2008, 10:37 PM

My vintage Speedy Pro manual provides this info regarding all four bezels:

The telemetric bezel was used as an artillery range finder. The chrono hand was started upon a muzzle flash and stopped when the shot was heard. The scale then revealed the range.

Fr. John+

gaopa · 3 December 2008, 10:54 PM

This is a very interesting and informative thread! Thanks guys! Cheers, Bill P.

vapalux · 23 December 2008, 04:54 AM

Hi Larry

Great posting and info. I have been wondering how it all worked

Si

oneillba · 23 December 2008, 07:24 AM

All very good and informative information, Guys. Thanks for posting.

PAMFanatic · 9 March 2009, 05:19 AM

good info.. thx

icnbne · 7 April 2009, 05:21 AM

I never even thought about using Tachymetre. For me, it was always about the look-factor. But great article, I learned a few things just then.

DadsWatch72 · 22 September 2009, 07:11 AM

Good thread. I have learned something today.

AWATCH · 22 September 2009, 07:23 AM

thanks for sharing

Ultraman · 22 September 2009, 11:09 AM

Thanks for the post and info, always wanted to know!

Dr.B · 22 September 2009, 11:16 AM

Thank you Larry....as always!!!
You never let us down

DadsWatch72 · 23 September 2009, 03:59 AM

I went to Jared's yesterday to look at them first hand. I was very impressed with Omega and they felt solid. I used the chrono function for the first time while shopping and I knew how to use the bezel.

RW16610 · 23 September 2009, 05:02 AM

Quote:

Originally Posted by DadsWatch72

I went to Jared's yesterday to look at them first hand. I was very impressed with Omega and they felt solid. I used the chrono function for the first time while shopping and I knew how to use the bezel.

Omega truly does make a nice, hefty watch indeed

Very useful topic here for those new to this feature

h3rt3q · 9 April 2010, 03:35 AM

Useful information. Thanks

jets · 9 April 2010, 05:08 AM

The telemetric bezel appears to be a useful tool to use when you're in need of it.

Rolexavidfan · 20 February 2011, 12:13 PM

Excellent post !

Rollingsculptor · 1 May 2011, 02:18 AM

Great posts - never thought of it in terms of manufacturing product - which is what I do!!! Duh.... Now I don't have to use my cell phone.... lol....

horseco · 6 May 2011, 02:13 PM

I am embarrassed to say, I have owned 2 Daytona's & had no idea what the bezel was used for... now I know, thanx!!!

Wineman · 3 August 2011, 09:03 AM

Quote:

Originally Posted by Gurmot

Another great article, and very useful too but aren't we forgetting another member of the Speedy bezel family?

Here's my 1967 cal 321 Speedy with a Pulsations or Doctor's bezel. It is used to measure heart-rate by recording the time it takes for 15 heart-beats. The watch is stopped after the 15th beat and the equivalent BPM is displayed.

What do you reckon to this one?

Cheers - Simon

Does under 40 mean the patient is dead? No readings lower!

Mickey® · 23 February 2012, 11:09 AM

Quote:

Originally Posted by Tools

Omega also produced a Decimal bezel for the Speedy as shown in this 1970 example.

This bezel was handy if you were interested in knowing hundredths of a minute..

For example; 15 seconds would be 25 hundredths of a minute, or in the case of this photo, the second hand is stopped at 22 seconds, which equals 37 hundredths of a minute.

Attachment 38048

O MY I love this watch...

mikkolopez · 28 March 2012, 10:37 PM

i own 2 Omega Speedy (a Pro and a Triple Date), 3 Tudor Tiger till now and I just found out today how to read the tachymetre bezel (never felt the need to know before), and I just thought they look cool on these watches since most of my dive watches are the normal 60 units bezel.

I get to know something new everyday.

caso.it · 17 April 2012, 12:39 AM

Nice post

GTS Dean · 6 May 2012, 05:07 AM

Is it possible to have a decimal bezel installed during factory service? Mine is under warranty, and needs regulation. It will probably get a new crystal installed, so this would be the best time to do the swap.

____________________________
TT OysterQuartz
SS/Black "U" Daytona
TT GMT II-C
DD OysterQuartz
Brietling Aero
Omega Speedmaster Pro

Npena240 · 2 July 2012, 12:20 PM

Great info. Thanks

50hz · 15 February 2013, 08:04 AM

very cool info, appreciate this post.

28 March 2008, 10:28 AM	#1
Tools TRF Moderator & 2024 SubLV41 Patron Join Date: May 2007 Real Name: Larry Location: Mojave Desert Watch: GMT's Posts: 43,490	Reading Your Bezel......Tachymetre/Telemeter The Tachymeter or Tachometer bezel on your Chronograph is a simple calculator for determining approximate speed in MPH/KPH, or determining a simple rate of production. For speed estimates, you need a measured mile or kilometer. As the object you want to time enters one point on the measure (milepost) start the stopwatch function of your chronograph. When it reaches the next milepost, stop the second hand. An estimate of mph is read off the bezel. Here is an example. The time to travel the measured mile took 20.2 seconds or ~179 mph SpeedyTachy-1.jpg Rate of production can also be determined. If you are watching an assembly line, or timing an event (say chugging a bottle of water), you start the timer at the beginning of the event. You stop after the end of the event, or when another product comes off the assembly line. Using our example above; if 1 widget was made during the 20 seconds timed, then 179 widgets are being produced per hour. Or you are chugging a bottle of water at the rate of 179 bottles per hour. There are more than one type of bezel or scale available for a chronograph. Some are marked with a Telemeter bezel. In the case of our next example below, it is the red scale. When a visual cue at a distance is observed, the timer is started. The timer is stopped when an audible cue that corresponds to the observation is heard. The approximate distance is read off the scale. Using our example below let's say that a lightning strike is observed, and then the event is timed until the thunderclap is heard. In this case, ~36 seconds, and our scale is calibrated in kilometers, so reading off the telemeter scale, distance is slightly over 12 kilometers away. In a military application, you can see the flash of the artillary, time the event until you hear the sound, and be able to know the approximate distance away the artillary is placed. LancoTachy-1.jpg One last type of bezel encountered is the decimal bezel. This is easily identified because it is calibrated from 1 to 100, Using this bezel, time is read off the bezel in tenths, or hundreds of a minute.. If you time an event and the second hand is stopped at exactly 30 seconds, the decimal bezel would reflect .50 of a minute. __________________ (Chill ... It's just a watch Forum.....) NAWCC Member Last edited by Tools; 19 February 2020 at 10:09 AM..

28 August 2008, 12:17 PM	#6
Tools TRF Moderator & 2024 SubLV41 Patron Join Date: May 2007 Real Name: Larry Location: Mojave Desert Watch: GMT's Posts: 43,490	Omega also produced a Decimal bezel for the Speedy as shown in this 1970 example. This bezel was handy if you were interested in knowing hundredths of a minute.. For example; 15 seconds would be 25 hundredths of a minute, or in the case of this photo, the second hand is stopped at 22 seconds, which equals 37 hundredths of a minute. Speedy Decimal.jpg __________________ (Chill ... It's just a watch Forum.....) NAWCC Member

23 December 2008, 07:24 AM	#10
oneillba "TRF" Member Join Date: Apr 2008 Real Name: Brian Location: Hamilton, MI USA Watch: My beloved TT DJ Posts: 3,831	All very good and informative information, Guys. Thanks for posting. __________________ My Trusty TT DJ

9 April 2010, 05:08 AM	#20
jets "TRF" Member Join Date: Dec 2008 Real Name: Mario Location: CANADA Posts: 2,483	The telemetric bezel appears to be a useful tool to use when you're in need of it. __________________ ♛ DJII 116234 · Submariner 126610LV · Yacht Master 42 226659 ✿ Pelagos 25600TN Ω X-33 Speedmaster Skywalker · 1861 Speedmaster Modsukoshi · SMP 2254.50 · SMP 2230.50 NAC · Seamaster 300 166.0324 · Genève 162.037 Seiko SLA033 Willard · SKX007

28 March 2008, 11:06 AM	#2
juneja "TRF" Member Join Date: Dec 2007 Real Name: juneja Location: London UK Watch: 6542 Posts: 217	My first Omega arrived today, and your timely post (ahem) now enables me to use her properly. Thank you!!

28 March 2008, 01:54 PM	#3
Wasatch "TRF" Member Join Date: Dec 2006 Location: Utah Posts: 17	Excellent post, Larry. Thank you.

28 August 2008, 11:29 AM	#5
yujinyboy Member Join Date: Aug 2008 Real Name: yuji Location: USA Watch: Rolex GMT IIC Posts: 16	nice information!

11 October 2008, 10:37 PM	#7
jmsrolls Banned Join Date: May 2008 Location: USA Posts: 3,185	My vintage Speedy Pro manual provides this info regarding all four bezels: The telemetric bezel was used as an artillery range finder. The chrono hand was started upon a muzzle flash and stopped when the shot was heard. The scale then revealed the range. Fr. John+

3 December 2008, 10:54 PM	#8
gaopa "TRF" Member Join Date: Jul 2007 Location: .. Watch: Rolex Explorer II Posts: 1,820	This is a very interesting and informative thread! Thanks guys! Cheers, Bill P.

23 December 2008, 04:54 AM	#9
vapalux "TRF" Member Join Date: Nov 2008 Real Name: Si Location: united kingdom Posts: 1,655	Hi Larry Great posting and info. I have been wondering how it all worked Si

9 March 2009, 05:19 AM	#11
PAMFanatic "TRF" Member Join Date: Mar 2009 Location: Singapore Posts: 12	good info.. thx

7 April 2009, 05:21 AM	#12
icnbne "TRF" Member Join Date: Apr 2009 Real Name: J Location: Brisbane Watch: Rolex Omega Seiko Posts: 1,562	I never even thought about using Tachymetre. For me, it was always about the look-factor. But great article, I learned a few things just then.

22 September 2009, 07:11 AM	#13
DadsWatch72 Banned Join Date: Jul 2009 Location: USA Watch: DRSD 1665 #3551XXX Posts: 2,401	Good thread. I have learned something today.

22 September 2009, 07:23 AM	#14
AWATCH "TRF" Member Join Date: Jul 2009 Real Name: al Location: GEORGIA Watch: Explorer II Posts: 1,759	thanks for sharing

22 September 2009, 11:09 AM	#15
Ultraman "TRF" Member Join Date: Apr 2009 Location: Australia Posts: 2,175	Thanks for the post and info, always wanted to know!

22 September 2009, 11:16 AM	#16
Dr.B "TRF" Member Join Date: Nov 2008 Real Name: Fernando Location: North Carolina Watch: SS White Daytona Posts: 1,944	Thank you Larry....as always!!! You never let us down

23 September 2009, 03:59 AM	#17
DadsWatch72 Banned Join Date: Jul 2009 Location: USA Watch: DRSD 1665 #3551XXX Posts: 2,401	I went to Jared's yesterday to look at them first hand. I was very impressed with Omega and they felt solid. I used the chrono function for the first time while shopping and I knew how to use the bezel.

9 April 2010, 03:35 AM	#19
h3rt3q "TRF" Member Join Date: Apr 2010 Location: USA Posts: 3	Useful information. Thanks

20 February 2011, 12:13 PM	#21
Rolexavidfan "TRF" Member Join Date: Jan 2011 Real Name: Har Location: Tukwila, WA Watch: Rolex Posts: 1,571	Excellent post !

1 May 2011, 02:18 AM	#22
Rollingsculptor Member Join Date: Apr 2011 Real Name: Eric Location: Vancouver Watch: Breitling Navi.... Posts: 21	Great posts - never thought of it in terms of manufacturing product - which is what I do!!! Duh.... Now I don't have to use my cell phone.... lol....

6 May 2011, 02:13 PM	#23
horseco "TRF" Member Join Date: Jan 2011 Real Name: Anthony Location: North Jersey Watch: Daytona 116528 Posts: 3,425	I am embarrassed to say, I have owned 2 Daytona's & had no idea what the bezel was used for... now I know, thanx!!!

28 March 2012, 10:37 PM	#26
mikkolopez "TRF" Member Join Date: Sep 2010 Location: Philippines Posts: 2,301	i own 2 Omega Speedy (a Pro and a Triple Date), 3 Tudor Tiger till now and I just found out today how to read the tachymetre bezel (never felt the need to know before), and I just thought they look cool on these watches since most of my dive watches are the normal 60 units bezel. I get to know something new everyday.

17 April 2012, 12:39 AM	#27
caso.it Member Join Date: Apr 2012 Location: Italy Posts: 18	Nice post

6 May 2012, 05:07 AM	#28
GTS Dean "TRF" Member Join Date: Feb 2011 Location: NB, TX Watch: 3570.50 Posts: 1,016	Is it possible to have a decimal bezel installed during factory service? Mine is under warranty, and needs regulation. It will probably get a new crystal installed, so this would be the best time to do the swap. ____________________________ TT OysterQuartz SS/Black "U" Daytona TT GMT II-C DD OysterQuartz Brietling Aero Omega Speedmaster Pro

2 July 2012, 12:20 PM	#29
Npena240 "TRF" Member Join Date: Jun 2012 Real Name: Nick Location: Miami, Fl Posts: 25	Great info. Thanks

15 February 2013, 08:04 AM	#30
50hz "TRF" Member Join Date: Oct 2012 Location: usa Posts: 140	very cool info, appreciate this post.

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