7s26A vs 7s26B vs 7s26C

[Deleted]

Dec 9, 2019 21:40:33 GMT -8 @treescientist said:

Dec 7, 2019 14:53:35 GMT -8 HiBeat said:

I am thinking maybe this is worthy of being a sticky in the tinkering area.

Thanks Peter !!!

Agreed! Also, a 6R15 A/B/C/D sticky would be helpful as well. And then somehow link both of them to the Watchuseek Seiko forum so we can stop the uninformed masses from starting new "Why the 7s26A is superior" and "Is the 6R15D REALLY better than the 6R15C?" threads every two weeks.

Well, I don't have access to any of them but I do remember that one of the main reasons they went from A to B was because the A had tried using the old 7s26A date wheel and it occasionally caused interference and stopped the watch. They may have also had to change the main plate to accommodate a new date wheel and mechanism. There may have been other changes as well.

I think that with the exception of the inventory rationalization changes, that each new version has been overall better than it's predecessor. The problems with hairspring looping were over weighed by other things that were actual improvements.

[SeikoPsycho]

Looks like you've done your homework Peter and have helped us all understand the differences and issues with the 7S26 balance assy.

Thanks for your efforts!

[filnabro]

Good Evening my friend ,  I need your advice about a choice I need to make. I can choose between 2 seiko monsters , the first one has the 7s26A mechanism and the second one the 7s26C mechanism. I have read your posts about the differences, however I am not sure which one is the best. Both of them look they work correctly. The seiko with 7s26A  externally is near mint condition and the other is also in good condition but not as good as the first one. Should I choose regarding the mechanism or the condition they are? Thanks a lot.

[HiBeat]

Mar 23, 2020 3:58:46 GMT -8 filnabro said:

Good Evening my friend ,  I need your advice about a choice I need to make. I can choose between 2 seiko monsters , the first one has the 7s26A mechanism and the second one the 7s26C mechanism. I have read your posts about the differences, however I am not sure which one is the best. Both of them look they work correctly. The seiko with 7s26A  externally is near mint condition and the other is also in good condition but not as good as the first one. Should I choose regarding the mechanism or the condition they are? Thanks a lot.

Get the one with the external look you prefer. 

A 7S26C can be purchased any day if you ever wanted to upgrade it to the modern version.  

[filnabro]

thanks for the answer! I have this dilemma because they are both in very good condition, however the older one has a little less saturated orange colour which I like more. They have different dials. The older has TG 2 and the newer one R2 . Also I see that at the 7s26A the date is better aligned with a little more bolt letters , like they are better printed. Also it has better rotating bezel as the newer one ( the one with 7s26C) rotates pretty easy in my opinion. I feel that the very early version has better overall construction and quality control. But I have read that 7s26A is ancient mechanism and I am concerned choosing it against 7s26C ...

[HiBeat]

Take the one you are clearly drawn to with the A movement.

These are WIS conversations don't lose sleep over A vs B vs C !!

[Deleted]

Mar 23, 2020 5:24:02 GMT -8 filnabro said:

thanks for the answer! I have this dilemma because they are both in very good condition, however the older one has a little less saturated orange colour which I like more. They have different dials. The older has TG 2 and the newer one R2 . Also I see that at the 7s26A the date is better aligned with a little more bolt letters , like they are better printed. Also it has better rotating bezel as the newer one ( the one with 7s26C) rotates pretty easy in my opinion. I feel that the very early version has better overall construction and quality control. But I have read that 7s26A is ancient mechanism and I am concerned choosing it against 7s26C ...

Check the serial number on the case back of the 'A' version. It could have been made as late as 2006 which isn't really all that old.

The first number tells you the year it was manufactured. If it is a '6' then it could be 1996 or 2006. Any other number will be in the 2000s.

As HiBeat suggests, go with the one that speaks to you cosmetically. When it comes time for a service down the road, just have your watchmaker drop in a 'C' version; it will cost less than the time he/she will charge for working over the old 'A' version.

[Myles]

Mar 23, 2020 6:50:22 GMT -8 HiBeat said:

don't lose sleep over A vs B vs C !!

That's what I used to tell my parents when I brought home my report card.

[jamca]

i really thank you for the answers. It starts with 5 so i suppose it was made back in 2005, which means it is not that old. Also it runs 40+ hours loosing around 2 minute every week max , which i suppose mean that it is in good working condition. It was a friend's of mine that was never used. 

[Deleted]

Mar 23, 2020 12:15:18 GMT -8 jamca said:

i really thank you for the answers. It starts with 5 so i suppose it was made back in 2005, which means it is not that old. Also it runs 40+ hours loosing around 2 minute every week max , which i suppose mean that it is in good working condition. It was a friend's of mine that was never used. 

17 seconds per day is well within spec. It could probably be tweaked for even better performance but for me this is more than acceptable

[coffee]

Sorry for resurrecting this old thread. 

As many know, Spencer Klein is a huge 7s26A fan. He recently said the 7s26A has more in common with the bulletproof 700x movements from the 70's/80's, than the B/C variants.

My 2006 1st Gen. Monster has the A version. I think I will always have it serviced, in order to maintain the A variant. Not a fan of movement swaps (seem a bit cold IMO). My watchmaker gives me a sweet deal for a full-overhaul, so it's actually less expensive for me have it serviced, than to buy+swap a NOS movement. Not a fan of upgrading it to an NH36 movement either.

Even though the A version lasted a decade (from 1996 until Oct. 2006), I think it will be harder to find in the future 7s26A, unmolested/modded versions. So many SKX007's were modded or had movement swaps later on.

BTW: Anybody know the exact month the 7s26A was introduced in 1996? I assume it's the same month the SKX007 was released. 

[HiBeat]

Jul 12, 2023 4:03:23 GMT -8 coffee said:

Sorry for resurrecting this old thread. 

As many know, Spencer Klein is a huge 7s26A fan. He recently said the 7s26A has more in common with the bulletproof 700x movements from the 70's/80's, than the B/C variants.

My 2006 1st Gen. Monster has the A version. I think I will always have it serviced, in order to maintain the A variant. Not a fan of movement swaps (seem a bit cold IMO). My watchmaker gives me a sweet deal for a full-overhaul, so it's actually less expensive for me have it serviced, than to buy+swap a NOS movement. Not a fan of upgrading it to an NH36 movement either.

Even though the A version lasted a decade (from 1996 until Oct. 2006), I think it will be harder to find in the future 7s26A, unmolested/modded versions. So many SKX007's were modded or had movement swaps later on.

BTW: Anybody know the exact month the 7s26A was introduced in 1996? I assume it's the same month the SKX007 was released. 

I can buy a brand new 7S26C from Seiko for less than $50 with tax

Your watchmaker must be a very economical choice

[HiBeat]

I totally get the desire to keep a watch all original and respect paying to overhaul a movement rather than drop and swap a new one, regardless of whether it costs less or more to do so.

All that said, the 7S26C is way better.  Look at the regulation system.  

I too have spare working 7S26A movements to use in period correct models.   I know a friend was bummed when Seiko Service Center swapped in a C and confiscated his A when he went it in under the premise of a "service".

[coffee]

Jul 12, 2023 5:53:18 GMT -8 HiBeat said:

Jul 12, 2023 4:03:23 GMT -8 coffee said:

Sorry for resurrecting this old thread. 

As many know, Spencer Klein is a huge 7s26A fan. He recently said the 7s26A has more in common with the bulletproof 700x movements from the 70's/80's, than the B/C variants.

My 2006 1st Gen. Monster has the A version. I think I will always have it serviced, in order to maintain the A variant. Not a fan of movement swaps (seem a bit cold IMO). My watchmaker gives me a sweet deal for a full-overhaul, so it's actually less expensive for me have it serviced, than to buy+swap a NOS movement. Not a fan of upgrading it to an NH36 movement either.

Even though the A version lasted a decade (from 1996 until Oct. 2006), I think it will be harder to find in the future 7s26A, unmolested/modded versions. So many SKX007's were modded or had movement swaps later on.

BTW: Anybody know the exact month the 7s26A was introduced in 1996? I assume it's the same month the SKX007 was released. 

I can buy a brand new 7S26C from Seiko for less than $50 with tax

Your watchmaker must be a very economical choice

In my neck of the woods, my watchmaker is actually one of the most expensive for Seiko servicing. He works for the Seiko Service Center, but I go to him directly since I've known him before. Here is my OM serviced a few weeks ago.



Thing is, here in Latin-America manual labor costs are way below what they charge in the United States. In USD conversion, around $50 is what he charges for a full overhaul.

Wow, $50 for a 7S26 movement from Seiko is a great deal. On Ebay they are around $80.

[HiBeat]

Amazing stuff there coffee !

Funny to see the Seiko tech uses proper Swiss Bergeon screwdrivers when they sell Seiko drivers as tools !

Happy for you sounds like a great arrangement.