Seiko Caliber 6r35

Seiko Caliber 6R35

Seiko Caliber 6r35a

ManufacturerSeiko
Caliber Number6R35, 6R35A
Movement TypeAutomatic
Diameter27.40mm (needs confirmed)
Casing Diameter
27mm (needs confirmed)
Height5.25mm (needs confirmed)
Jewels24
Vibrations Per Hour
21,600 bph
Lift Angle
53 degrees
Shock System?Diashock
MainspringSpron 510 (needs confirmed)
Regulation
ETACHRON
Power Reserve
~70 hours
Rotor Direction
Bi-directional (Magic Lever)
Hacking?Yes
Hand-Windable?Yes
Magnetic Resistance
4,800 A/m (60 gauss)
FunctionsHours, minutes, central second hand, date at 3:00
Country of ManufactureJapan
Known Models
Presage models: SPB127, SPB131, SPB129, SPB115, SBP113, SPB095 (Arita), SPB111 / Prospex Alpinist: SPB117 (SBDC087), SPB119 (SBDC089), SPB121 (SBDC091), SPB123 (SBDC093) / Prospex “Sumo”: SPB101, SPB103, SPB125 (Add more in the comments below)

The Seiko caliber 6R35 is an automatic movement that is part of what Seiko refers to as the high performance 6R series caliber. The 6R35 is considered an upgrade from the caliber 6R15. Watches with the 6R35, such as the Presage Arita Porcelain were announced at Baselworld 2019. The Prospex SPB149 powered by the 6R35 was announced in March 2020.

6R15 VS 6R35:

The caliber 6R35 is beginning to find its way into watches that used to house the 6R15. The biggest difference between the two movements is a 20 hour increase in power reserve. The 6R15 has a power reserve of approximately 50 hours and the 6R35 has a power reserve of approximately 70 hours.

6R35 / 6R35A / 6R35B / 6R35C:

This is still a rather new movement, so currently there is only the 6R35A. The general caliber number is 6R35, with 6R35A being the first version. The subsequent letter variations indicate evolution stages in the movements development. This post will be updated if the movement gets any upgrades.

Accuracy of the 6R35:

Seiko claims the accuracy of the caliber 6R35 has a rating of -15/+25 seconds per day in normal temperature conditions (between 5 – 35 degrees C).

Seiko says this about accuracy:

  • The accuracy of mechanical watches may not fall within the specified range of time accuracy because of loss/gain changes due to the conditions of use, such as the length of time during which the watch is worn on the wrist, arm movement, whether the mainspring is wound up fully or not, etc.
  • The key components in mechanical watches are made of metals which expand or contract depending on temperatures due to metal properties. This exerts an effect on the accuracy of the watches. Mechanical watches tend to lose time at high temperatures while they tend to gain time at low temperatures.
  • In order to improve accuracy, it is important to regularly supply energy to the balance that controls the speed of the gears. The driving force of the mainspring that powers mechanical watches varies between when it is fully wound and immediately before it is unwound. As the mainspring unwinds, the force weakens.
  • Relatively steady accuracy can be obtained by wearing the watch on the wrist frequently for the self-winding type and winding up the mainspring fully everyday at a fixed time to move it regularly for the wind-up mechanical type.
  • When affected by external strong magnetism, a mechanical watch may loss/gain time temporarily. The parts of the watch may become magnetized depending on the extent of the effect. In such a case, consult the retailer from whom the watch was purchased since the watch requires repair, including demagnetizing.

Power Reserve:

The caliber 6R35 holds a power reserve of at least 70 hours. To fully wind the mainspring, turn the crown a minimum of 55 times.

Crown Position Functions:

0 (against the case): Clockwise = Manual Winding / Counterclockwise = Nothing
1 (pulled out one click): Clockwise = Nothing / Counterclockwise = Date setting
2 (pulled out two clicks): Time setting clockwise and counterclockwise

Can you overwind the movement?

No. According to the Seiko documentation, manually winding the movement after it is already fully wound will not break the spring.

When can you adjust the date?

Do not adjust the date between 9:00 PM and 1:00 AM.

Stem Removal:

To remove the stem, make sure the crown is in position 0 or normal position (not date or time setting position). There is a lever with a small indentation for your tool. Gently press down while pulling the stem out. See official instructions below for more guidance:

Seiko Caliber 4r36 Stem Removal

How often does the 6R35 need serviced?

According to official Seiko documentation, watches with the caliber 6R35 should be serviced every 2-3 years. Learn all about Seiko service intervals here. At the time of this post, the starting cost of getting this movement overhauled by Seiko is $260.00 USD.

Examples of watches with caliber 6R35:

Additional Resources:

  • Seiko 6R35 official instruction manual here
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Jyrgen N
Jyrgen N
4 months ago

The 6R35 is also in the SPB113J1 (Presage with white enamel dial) I bought two weeks ago. So far I have observed deviations from +3 to -3 s per day; the day I saw the latter may have been one with very little activity. So far I am as happy with the caliber as with the watch in general, meaning *very* happy.

Jyrgen N
Jyrgen N
4 months ago
Reply to  Jyrgen N

The above was during a time when I had relatively little activity during staycation. In between I have seen that in a normal work week the clock gains about 20 seconds, meaning around +3 seconds per day on average. Good!

Don Jones
Don Jones
4 months ago

It’s also in the new SPB151 & SPB153 models

Bryan W
Bryan W
2 months ago

Also in the SBDC101/SPB143 series MAS62 reissue watches.

Gareth Davies
Gareth Davies
2 months ago

With regard to my SPB143J1, I am getting +15 seconds a day. Quite disappointed really.

zeke
zeke
1 month ago
Reply to  Gareth Davies

that will slow down over a month run in time…i have spb149 and for the first few days it was +1 a day now afther 3 weeks of 24/7 wear its now -10 per day

Gareth Davies
Gareth Davies
1 month ago
Reply to  zeke

Alas, after two weeks my watch was gaining up to 28 secs a day. Spoke directly to Seiko, who asked me to return the watch for adjustment and have subsequently written to me explaining they will rectify any defects, but it will take at least 3 weeks to test the watch properly. Will keep you posted as how the watch performs once returned to me.

Gareth Davies
Gareth Davies
25 days ago
Reply to  Gareth Davies

Received my watch back from Seiko after 4 weeks. They have replaced the entire movement, all under warranty. It’s currently gaining gaining plus 9 secs a day, but hopefully it will bed in and improve. Fingers crossed

trackback
Reseña SEIKO SPB143 – SaFonaGastroCrono
1 month ago

[…] finalizar hablaré de su calibre, el movimiento automático 6R35, la evolución del 6R15. Ha aumentado su reserva de marcha hasta las 70 horas y su latido es de […]

Benjamin Kingsmill
Benjamin Kingsmill
24 days ago

It gains too much time in a day! I’m constantly readjusting it, wish it was a quartz! So disappointed for an £740 watch!

Benjamin Kingsmill
Benjamin Kingsmill
24 days ago
Reply to  Caliber Corner

Hi, yes I checked to see if my seiko sumo 3rd gen was magnetised with this ‘Lepsi’ app you can download, and it was showing that it is not at all. My watch is only a few months old, I have wound it up fully and then let it unwind all the way down ( which was recommended on another watch site) and then wound it back up and worn it for 3 weeks, it… Read more »

Gareth Davies
Gareth Davies
24 days ago

Ben, if you are in the UK. Speak to Beverly in Seiko customers services. Explain your situation and return the watch to them. If the movement needs changing, they will. She’s very understanding and obliging. Your watch comes with a warranty for a reason. The 6R35 is not bullet proof. I know that and so do Seiko.

Benjamin Kingsmill
Benjamin Kingsmill
24 days ago
Reply to  Gareth Davies

Ahh thanks so much Gareth! Really appreciate this thread and website forum, and speedy assistance!.. I have just wound my watch up again and set it to the speaking clock and I will monitor carefully for a week just so I have definitely got my facts straight and then if still the same, and I see no reason why it won’t be!, I will send it in, from your advice! All the best , and… Read more »

Myles
Myles
5 days ago

Hi, Ben.

Does the Lepsi app require you to place your watch in close proximity to your phone? If so, that’s an excellent way to *magnetize* a watch movement! Instead, use a small compass, or better yet, buy a cheap demagnetizer and treat the watch empirically with the demagnetizer. It can’t hurt.

Good luck!

Myles

Bari W
Bari W
22 days ago

JUNK. Absolutely junk of a movement. Bought my SBDC101 (aka SPB143) with this 6r35 movement, and the quickset date no longer works… Extremely disappointed in Seiko. Luckily I have warranty, so I will get this watch fixed. I bet they will charge me to ship it over to Japan too. As soon as I get this watch fixed I am going to sell it off… doubt I will ever try another Seiko again. It’s a… Read more »

Laurens vH
Laurens vH
17 days ago
Reply to  Bari W

Dear Bari, I can imagine you are disappointed, but your are now basing your evaluation of the Seiko brand off one bad experience. If I did the same I couldn’t buy any Rolex (misaligned bezel on a GMT Master) or Omega (1 minute a day fast on a Speedmaster) or any watch from any brand for that matter. Sometimes bad ones slip through QC, and sometimes stuff breaks… Seiko’s are (very) good watches and offer… Read more »

Mike T
Mike T
11 days ago

The book says 20 winds to get it going and no damage done if you over wind. Saw a comment saying 50 winds to max its out. How many winds to do….

Max
Max
4 days ago

Just got an SPB149J1 second hand with blank warranty card. Really liked the look of it and splurged for my first seiko. (too bad it was sold out everywhere pretty fast) Running +45 seconds per day :-(. Will seiko honor their warranty on it or with a blank card I am stuck. Also the bezel feels weird as after the click it still has a bit of play. Is it normal? Has anyone experienced this?… Read more »

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