Rolex's Updated Explorer II & GMT II-C

Updated: Explorer II Service

GMT-C 116710 BLNR Explorer II Service

Rolex's traditional GMT and Explorer II models shared the same case and movement, but the new Ref 216570 Explorer II sports a new movement, updated size, updated luminescence and other refinements that separate it from its GMT-C brother.

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Rolex Explorer II & GMT II - C

The new and updated 216570 Explorer II debuted at the Basel 2011 show.  The increased case size to a 42m , the updated luminescence, Paraflex shock mechanism for the balance wheel, and of course the orange hand, make the Explorer II stand out from the rest of the Rolex line.

Initially, when initially released at Basel in 1971 Explorer II did not garner much attention. It had a fixed bezel, unlike the GMT's, and was considered one of the more stealthy Rolexes because it had few polished refinements, and no color unlike the two-tone bezel inserts on the traditional GMT's and it rode low on the wrist.
Rolex GMT-C & Explorer II Booklets Rolex Explorer II Orange Hand
The new Ref 216570 Rolex Explorer II changes all that as the updated model is about size, presence, and orange. The orange 24 hour hand, along with the orange Explorer II on the watch face are subtle refinements that make this watch stand out from the rest of the Rolex line. Unlike the GMT-C and other Rolex sport watches, the Explorer II has a black matt dial, similar to the Deep Sea and Milgauss models. The black matte face creates more contrast against the larger Explorer II hands, and it makes it easier to read the engraved Rolex emblem on the watch crystal located at the 6 o'clock hour marker. The larger super-maxi hands hold extra lume, and they are easier to read. The hands are painted black in the center section so that they have a floating effect above the dial. Even on the Rolex manuals that are included with the watch, the orange hand is intended to stand out.
Rolex Explorer II & GMT-C size comparison
GMT II - C Explorer II
On the left is the GMT-C and on the right is the Explorer II. The case thickness between both watches is very similar with the GMT-C being 12mm and the Explorer II being 12.45mm. The Explorer II case is slightly longer as it is wider being 48.70 long versus 46.38mm on the GMT-C. The image does not adequately capture how the Explorer II case has more of a curvature than the flatter GMT-C case. The weight of both watches is very similar with the GMT-C being 145g versus the Explorer II being 150g (weighed with two links removed from the bracelet).


One of the chief complaints on the traditional GMT and Explorer II models was that the Twinloc crown was too small to operate. Rolex answered that criticism on the GMT by adding the larger Triploc winding crown found on the Submariners onto the GMT-C.

Rolex answered the same small crown criticism on the new Explorer II by fitting it with a larger 7mm Twinloc crown, the same one that is found on the Milgauss rather than the traditional 6mm crown. Although not as water resistant as the Triploc, it is still plenty water proof and the 1mm larger size makes it easier to operate.

Rolex Crown
Rolex Crown

Another production refinement on the Explorer II is that the winding crown lines up vertically. The crown lined up vertically on three different Explorer II modelsI saw, but others have reported that this is not always the case. Hopefully Rolex realized that discerning Rolex wearers would turn down a purchase if the crown did not line up vertically. Additionally, having a vertical crown makes it easy to see if the crown is screwed down fully before going into water. Hopefully, vertical crowns will be more prevalent.

Rolex GMT Rolex Explorer
GMTII - C Explorer II

One of the appealing aspects or the Explorer II is that its size is proportionate. The lugs are 21mm wide, larger than the 20mm GMT-C, but it is not noticeable because the lug horns are now much more tapered like the original Explorer models, unlike the boxier lugs found on the GMT II-C and other updated Rolex models. The images above show a traditional GMT bezel insert laid on the bezel of the GMT-C (left) and the Explorer II (right). The bezel insert almost fits perfectly on top of the GMT-C bezel whereas there is a good 1mm difference on the bezel size on the Explorer II. The watch is larger, but it does not seem so because every increase is proportionately so. The crystal width on the Explorer II is 32.62mm and the GMT-C is 30.50mm (approximately).

One of the refinements on the Explorer II that is not found on any other Rolex other than perhaps the fixed-bezeled Daytonas, is the polished bezel edge. On the traditional Explorer II, this refinement was lost, but on the larger and thicker bezel, the polished edge is a standout feature. Rolex Explorer II
Rolex Crystal on the Explorer II Another aspect of the Explorer II that goes unnoticed is the slightly raised crystal. Unlike the GMT-C and other ceramic bezeled watches, the crystal is slightly raised. Initially, the raised crystal edge was thought to be prone to chips, unlike the more recessed GMT-C crystal. The advantage I discovered when wearing both watches is that more light comes onto the watch face on the Explorer II. This subtle difference is noticed only when the GMT-C and the Explorer II are used by the same person.
Rolex GMT-C and Explorer II Rolex GMT-C & Explorer II Luminescence

Rolex claims to have improved the luminescence on its watch hands. The greenish Super Luminova used on the GMT-C is plenty bright. If the watch has been outside all day in sunlight, it will glow all night. My experiences in the Grand Canyon have proved this to be true. The improved blue Chromalite luminescence used on the Explorer II does not appear to be brighter in intensity, but Rolex claims that it glows longer and I would have to agree. I have found that the blue luminscence glows brighter in twilight conditions (sunset) than the green lume version. The color difference appears similar to seeing blue headlights in automobiles; blue headlights are not necessarily brighter but they are certainly easier on the eyes. Despite the claims for longer luminosity, the larger hands, larger face, more lume, and the bright orange hand make the Explorer II an easy watch to read day and night, more so than the any other Rolex model I have owned, including the DeepSea SeaDweller

The 24 hour hand on the Explorer II is easier to read at night as it does not blend in like the GMT-C 24 hour hand. Tthe GMT-C 24-hour hand is hard to discern from an hour dot at night (as shown in the above right image). The Explorer II second hand is also much more visable at night and is not lost in the hour dot glow as other models. The larger hands in the new Explorer II and Chromolite lume make a very discernable difference.

The guys on the Prodical Guideshare that the Rolex Chromolite blue is similar to Timex indiglo. Frankly, I don't care what they say, Chromalite is better than the original green lume.

The GMT-C caseback is a little flatter than the Explorer II. The Explorer II caseback is a little more raised. Even though Explorer II rides slightly higher, the watch does not feel top-heavy. Rolex casebacks
Kello & GMTII Kello & Explorer II
GMT II - C Explorer II
Like other Paracrom Blu watches that I have owned, the Explorer II starts slow, but after a few months, it speeds up. Using Kello, an iPhone app shows the GMT-C on the left, and the Explorer II on the right. The GMT-C started out approximately -2 seconds/day out of the box in 2006, but runs approximately +2/day five years later. The Explorer II starts out approximately -1 second/day out of the box, but like the M series 16710 as well as the 116710/GMT-C, it is anticipated that the Explorer II will speed up as the years progress. Update: Three years later, my Explorer II is +0 to +1/day. I now set the time exactly to atomic time without having to worry whether the watch is slow or not. I have yet to have a Parachrom hairspring Rolex that has not gained rate over time.
3187 Movement Paraflex
Rolex Paraflex
The Rolex 3187 movement sports Paraflex balance staff shock protection. Paraflex is a shock absorber patented and developed by Rolex who claims that it increases shock absorption by 50% over other industry standard shock systems such as KIF or Incablock.  Rolex introduced Paraflex in the updated Rolex Day-Date II / President a few years ago and is becoming more commonplace in newer Rolex movements such as the 3187. (Photo Credit: Jake's Rolex Magazine)
Rolex Explorer II


My pals at Fourtané, the AD who sold me the watch think that this watch is going to be as popular as the Submariner because of its presence, its proportion, and the orange highlights. I completely agree. After wearing this watch, it is not top-heavy, is as comfortable as any of the GMT's, and rides well on the wrist. This watch is definately a keeper, and I am sure that many others will agree.

The 24 hour hand is set to local time such that when the hour hand is pointed towards the sun, the 24 hour hand points north (only in the Northern hemisphere; read the watch upside down with the watch overhead for this to work in the Southern hemisphere).

Choosing between the two watches is hard. The GMT-C weights and wears approximately the same as the Explorer II and has similar mechanical features. If having a third time zone is important, get the GMT-C. The Explorer II has more wrist presence, feels a tad-bit heartier and is more readable than the GMT-C, although the GMT-C is not a tough watch to read. Rolex GMT-C & Explorer II

Rolex GMT Ref 116710 BLNR & Rolex Explorer II Ref 216570

I was able to borrow a GMT 116710 BLNR from Fourtané for an Everest Strap review on A Blog to Watch. While I had the 116710 BLNR, I made some quick comparisons to the Explorer II 216570.

The blue–black bezel is a first in the watch industry and known within the Rolex cognoscente as the Rolex GMT Bruiser or GMT Batman because of its iconic colors.  Solid colored ceramic bezels are nothing new to Rolex, but the GMT BLNR (BLNR for bleu/noir or blue/black) is the first time two colors are incorporated into one ceramic bezel insert by any Swiss watch company, and the research Rolex pursued to accomplish this feat is well worth the effort.

Rolex 216570 & Rolex 116710 BLNR

You quickly notice the BLNR bezel, but the blue does not shout at you like the traditional red/blue Pepsi bezel, and the transition between the blue and black is seamless both technically and visually.

The photo on the right shows how the Explorer II is slightly larger, and the dial has slightly more luminescence, but in the dark shown below, is virtually indiscernible.

Rolex 216570 & Rolex 116710 BLNR

The casebacks do differ with the Explorer II (right) being larger in diameter, and riding slightly higher. The Explorer II flat section is also larger in diameter.

Rolex 216570 & Rolex 116710 BLNR

With the bracelets removed and the caliper out, I was able to take the following measurements:

Endlink Width 21mm 20mm
Lug - Lug Length 50.1mm 48 mm
Height 12.5mm 12mm
Width inc/crown 45mm 44.3mm
Weight w/o bracelet 83g 75g

All the way around the Explorer II 216570 is a larger and heavier watch, but just so slightly. The visual difference is subtle, with slightly more wrist presence going to the Explorer II.

The Explorer II's slightly raised crystal does allow more light to hit the watch face. When combined with the Explorer II's larger dial dots and hands, the watch reads much different than the GMT BLNR.

Rolex 216570 & Rolex 116710 BLNR

The bracelets are identical in shape and feel, but the Explorer II has the 21mm solid endlink (top) rather than the 20mm solid endlink (bottom). Yes, the Exp II bracelet (top) shown on the right has a Glidelock clasp discernable by the longer clasp cover. I added the Glidelock after I purchased the Exp II for which I have a description here.

The polished center links found on the GMT -C braclet have a deep polish that continues to shine even after being scratched.

Rolex 216570 & Rolex 116710 BLNR
The Chromalight luminescence on both the Explorer II (left) and the GMT (right) glows brightly. The larger hands and dial dots found on the Explorer II does make somewhat of a visual difference, but reading the GMT was no less difficult. Rolex 216570 & Rolex 116710 BLNR
Rolex 216570 & Rolex 116710 BLNR Rolex 216570 & Rolex 116710 BLNR

To demonstrate how much 1mm makes in the fitting of a Rolex endlink, I installed the 20mm GMT bracelet onto the 21mm Explorer II watch. The .5mm on each side of the solid endlink is visibly and operationally significant.

It is a toss-up between the Explorer II and the GMT BLNR. Wearing the GMT 116710 BLNR is an easy affair.  The black – blue ceramic insert is not as bold as the traditional red-blue insert, yet has subtle contrast to set this watch apart from others.  The blue 24-hour hand disappears into the watch face but provides better contrast for the 24-hour indicator triangle at the end of the hand making the triangle appear like it is floating above the watch face.

The Explorer II is larger, has slightly more wrist presence, and is much more understated than the GMT BLNR. Either way, there is no bad choice here.

Explorer II 216570 Service

For about two weeks, my Explorer II 216570 started running slow, then it stopped. Although the watch had a full wind, the hands failed to run normally. I took the watch to my local Rolex - AWCI certified (CW21) watchmaker and he thinks he found the culprit pictured on the right.

This is the 24-hour hand click mechanism that when viewed under inspection, was scored. Apparently, these are normal 3186/3187 movement service replacement parts.

Rolex 216570 Service
Here are the parts viewed next to my rollerball pen. The components consist of a spring, pin, and two wheels. All of these were replaced. Rolex 216570 Service
Also replaced was the Paraflex jewel clip. Although the clip was not broken, the watchmaker indicated that the clip felt weak upon installation so he replaced it. Rolex 216570 Service
Here is an idea how small this clip really is. Rolex 216570 Service
The watch was completely serviced utilizing Rolex replacement parts and will run flawlessly for years to come. This repair shows that Rolexes are not completely foolproof, but when serviced by a Rolex certified watchmaker -availability to Rolex genuine parts makes all the difference. Rolex 216570 Service

24-Hour Hand Pointing North

One neat feature of the 24-hour hand found on the GMT-C and Explorer II models is that when the 24-hour hand is set to local time, it points north when the 12 hour hand points to the sun (Northern Hemisphere).

Rolex 24 Hour Hand
This is another method for 24 hour hand-less watches, but the 24-hour hand is between the minute and 12-hour hand when the 24-hour hand is set to local time. Rolex 24 Hour Hand
Rolex 24 Hour Hand Rolex 24 Hour Hand
For the Southern Hemisphere, hold the watch overhead, or do the what the right images illustrate.
According to Rolex, the Rolex Explorer II can be used as a solar compass for orientation during expeditions: at whatever time of the day, simply pointing the hour hand towards the sun while holding the watch horizontally will result in the orange 24-hour hand indicating the north in the northern hemisphere, or the south in the southern hemisphere. The only requirement is that both the regular and the 24-hour display are set to the local time. Rolex Explorer II 216570

A great article on why its important to have an accurrate watch by Shane Griffin is here.

Photo Courtesy of HQ Milton

GMT 1675