The Parachrom Blu hairspring has been... - GINAULT

A Modern Rolex Anomaly
The Parachrom Blu hairspring has been one of the many advancements Rolex has incorporated into
their movements. With the exception of the Daytona that incorporated the Parachrom Blu back in
2003, none of the traditional movements had this hairspring, nor any of the latest Rolex
advancements. It had been rumored that the late Z series and M series 16710's had the new 3186
movement. After month's of this urban myth being bantered about, Tahoeblue,
on Timezone and Vintage Rolex Forumshowed these images of opening four M series 16710
GMT's and looked inside. He found 3186 movements and the discovery was verified byFourtane
Jewelers, a Rolex AD located in Carmel, California. The original TimeZone and Vintage Rolex Forum
posts I have captured in a 500kb .pdf file here.
Other forum readers have discovered or confirmed the existance of a 3186 movement in 16710's.
Sleedawg on The RolexForum also saw a stick font GMTII at the San Francisco Certififed Rolex
Service Center in March 2008. The Rolex Forum member, Scarface, in this post, shares that he
confirmed with a Rolex representative at Basel 2008 that the dials with the stick II is not a misprint,
but intentional to designate which 16710's have the 3186 movement. Kai on The Rolex Forums took
his M serial M305xxx GMTII 16710 pepsi with stick dial to an RSC, and they confirmed it to have a
3186 movement. He noted that the interesting part was that they would not open the case because
there is nothing wrong, but in the service report they wrote 3186!
The 3186 movement includes the Parachrom Blu hairspring (videos), and according to James
Dowling in a TimeZone post, the wheels of the drive train are closer together removing some of the
gear play felt in the 3185 when the hour hand was being set as well as the Parachrom Blu hairspring.
Anyone new to Rolex would not notice, but when comparing a 3185 next to a 3186 side-by-side, there
is a discernable hand-slop when setting the hour hand of the 3185 movement than on the 3186
movement. The crown on a 16710 with a 3186 movement is said to be more stable. Now known as
the "wiggle test," this is one of the very noticable methods to distinguish between a 3185 and a 3186
movement without removing the caseback. More on the Wiggle Test as well as the Crown Method is
shown below.
The Card
There is no information as to why Rolex may have
produced these watches. Some have speculated that they
were a test prior to the new 116710 GMT IIC, but this
would certainly not seem correct given the late production.
Some have also speculated that Rolex had more 16710
cases than older 3185 movements to match, but people
also doubt Rolex has run short on the 3185. The warranty
card on the left indicates an N for Noir (Black bezel). The
Red/Black bezels have an "A" designation and Red/Blue
has a "B" designation on the card (image at bottom of the
page) (click for larger image)

The Case
the Stick Font II are listed below.
(click for larger image)
This is certainly a rare anomaly of Rolex production. All
four are M serials two came with black bezel and two with
Pepsi bezel. There is no notation on the paperwork or
otherwise to indicate they have the 3186—-the only way to
determine the type of movement is to open the watch to
confirm. Another possible example in Finland (with Z serial)
has been mentioned in a previous post on the watch
forums. You will also notice that the pictured watch has an
unusual dial—-the "II" of "GMT-Master II" is in "non-roman,"
or "stick" font. The stick II on GMT's have been bantered
about regarding the GMT's collectability and possible dial
printing error. There are many GMTII's with the same dial,
presumably without the 3186. Interestingly all four of the
noted 3186 GMT II’s have this dial variant. More images of
Caseback Removed
There was thought that one reason Rolex increased the
case thickness for the new 116710 was to accommodate
an increased height of the 3186 calibre. But as as the
photos show, the 3186 fits nicely in the older case.
(click for larger image)
This picture from
another source
shows the
Parachrome
hairspring, but
look closely, the
baseplate
appears to show
3185.
(click for larger
image)

It's definately a 3186
The 3186 on the movement definately insures the
movement number.
(click for larger image)
... And another 3186
Charles
Newgass
on Timezone
purchased a
late
series M3XXXXXX Coke bezeled 16710. He indicated that when unscrewing the crown and changed
the 24 hour hand, none of the hands wiggled, a tell-tale sign between a 3185 and 3186 movement as
the wheel train is closer together on a 3186.
Charles had the back removed and found a 3186 movment.
(click for larger image; photo used with permission)
Distance to the Crown
The thickness between the crown and the movement is
definately less than the upgraded 116710 case. This is
definately a traditional 16710 case.
(click for larger image)
Tahoeblue definately blew this urban myth. Our thanks to
his fortitude on correcting what many had thought was
sheer nonsense. With this discovery, there is a good
chance that M-series Explorer II's might have the same
3186 movement.
-Pictures and text re-posted with permission from Tahoeblue.