Mühle Terranaut I Trail Review


Mühle Glashütte is no stranger to making tough and unique dive watches, as we saw in our review of the S.A.R. Rescue Timer. Their interests, however, go beyond the depths of the sea and into land and air too. While pilot watches are a very common thing (surprisingly common when you think of how many people are actually pilots…), watches that are designed for land sports, by which I mean biking, hiking, etc… are oddly less common. With their Terranaut Trail line, Mühle has set out to make watches for this very purpose.


With designs inspired by pilot’s watches, the Terranaut’s have a restrained and attractive look with an emphasis on legibility. Big hands and markers, all in khaki, are the signature of the line adding an earthiness to the palette that speaks to their purpose. Inside, the watches all feature Mühle standard over the top movement modification, making these a pretty unique offering. Of the three watches currently available, the Terranaut I Trail stands out a bit, as it has a particularly interesting dial and features Mühle’s MU 9408 chronograph movement (which has a Valjoux 7750 base). Coming in at $3,335.00, the Terranaut I Trail is a unique watch with a distinct design, but a heavy price tag that reflects the custom movement within.

Movement: MU 9408
Dial: Black
Lume: Super LumiNova
Lens: Sapphire
Strap: Leather
Water Res.: 50M
Dimensions: 44 x 53mm
Thickness: 14 mm
Lug Width: 22 mm
Crown: 7 x 5 mm
Warranty: Yes
Price: $3,335.00


The Terranaut I Trail’s case design has its roots in pilot watches. It’s a simple, no fuss design that get’s the job done, but still has a hint of elegance. At 44 x 53 x 14mm the satin/brushed PVD case is large though doesn’t seem oversized or out of proportion. As with pilot’s watches, the intentions behind the design are visibility in an active environment, so the scale has purpose.


From above, the case has a classic shape with a cylindrical center and long, slender lugs that sweep in smoothly. From the side, the multipart construction is more apparent and illustrates a couple of features that add up to a more wearable watch. As with most cases, the Terranaut is broken up into a bezel, central body and case back, but the proportions of the three are a bit different than standard. Usually the central body dominates the profile, but here the three are more equal, with a tall bezel that chamfers towards the sapphire crystal, a thin body and a gently domed case back. The domed case back and thin central body make the watch wear thinner than 14mm would suggest.

On the right side of the case are the two chrono-pushers as well as a 7 x 5mm screw-down crown. The crown is nicely designed and proportioned, with an easily graspable coined side and molded windmill logo on its end. The chrono pushers have a cuffed design that makes them appear as though they are screw down, though they are not. The cuff, which has a similar coined texture, does add robustness to them and potentially some protection against hits from the side. Aesthetically, I think it works nicely as it adds some ruggedness to the design.


The gently domed case back, which is also PVD, is held in place by 5 small screws. In the center is a large display window, showing off the nicely decorated MU 9408 movement that powers the watch. Naturally, this is appreciated as Muhle does go above and beyond the norm with their treatment of movements functionally and aesthetically, which contributes largely to the price of the watch.


The dial of the Terranaut I Trail has a lot of personality, mixing legibility with some unique style and a notably striking seconds hand. On the matte black face are several indexes and sub dials, as this is a chronograph, presented in either khaki or dark grey. The primary hour index is non-numerical, consisting of thin yet bold rectangles that don’t vary in shape or size, save where they are interrupted by a sub dial. On the peripheray of the dial, out side of the hour index, is a minute/second index in dark grey, which has numerals at increments of 5, and small hash marks in between.


As with most Valjoux 7750 based chronographs, there are three sub dials; a 30 minute totalizer at 12, a 12 hour totalizer at 6 and the active seconds at 9. The chronograph totalizers are large proportionally to the dial, but work well with overall design. Both are outlined in khaki with indexes consisting of khaki markers, which connect to the outline as well dark grey lines and numerals. To further distinguish these areas from the dial around, the entire sub dial has been given a satin finish, which both makes them appear darker than the surrounding areas and reflect light in a different manner.

The active seconds subdial at 9 is much smaller than the chronograph totalizers, but also features a khaki border. The second hand, which Muhle refers to as the “constantly rotating function display” is the most unique visual element of the watch. Instead of your typical hand shapes, they went with an equilateral triangle that matches the diameter of the sub dial, and rotates about its center. One of the points of the triangle has been marked with a line, to create some sense of a hand, though the purpose of the triangle is more to show that the watch is active. Visually, it is quite striking, giving the watch a lot of personality.


Text on the dial is limited to the brand logo above the day/date window at 3 and “made in germany” in fine print around 6. The day/date is presented in white on black, keeping it fairly unobtrusive. Considering that Mühle rebuilds their movements fairly extensively, I was a bit surprised to see that they didn’t go the extra mile and make the text khaki to match the motif.

Other than the triangular active seconds, the hands on the Terranaut are pretty straightforward, with standard shapes. The main hour and minute are long and relatively thin Roman swords, speaking a bit to the pilot watch undertones throughout, with black edges and khaki color lume. The chronograph seconds is a thin khaki stick with a triangular tip and the chrono hours and minutes are thick fence posts. Overall, the hands match with the style of the watch well, maintaining legibility, adding some sportiness and being well proportioned.


The dial features SuperLumiNova on the primary index as well as the minute and hour hands. Unfortunately, that limits the chronograph function a bit and I did expect (nay, want) the active seconds triangle to glow as well. Overall, the lume is average, but not exceptional, like it was in the SAR. The mix of lumed khaki and non-lumed also makes for some color variation on the dial. The lumed areas are paler, with a hint of green while the non-lumed are a touch pink.

Overall, I think the dial is very successful. It’s stylized enough to be unique and memorable, yet not so over the top as to be novel. I love the use of khaki and black instead of typical white or green. The watch is the “Terranaut Trail”, and the khaki has an earthiness to it that speaks to the concept of the watch. It’s also a bit subtler that white or green, yet has enough contrast to really pop off the black. That said, the khaki or “old radium” lume brands use tends not to be very potent.


The MU 9408 movement inside of the Terranaut I Trail is Mühle’s rebuilt Valjoux 7750 Top. Unlike other brands that just perhaps re-decorate or regulate (not to degrade those features) Mühle takes the whole thing apart, refinishes it and adds several in-house components, a treatment they do to all of their watches to varying degree. In the case of the MU 9408, they added house made blued screws, a Glashütte ¾ plate with perlage, their patented woodpecker neck regulation, the automatic bridge and the rotor. All of these features have functional as well as aesthetic benefits, such as the screws which are more corrosion resistant and the ¾ plate which has a removable escape wheel bridge for easier maintenance of the movement and the woodpecker regulation, which adds shock protection. Lastly, they regulate the movement to 6 positions, guaranteeing accuracy.


The decoration of the MU 9408 is beautiful. Chronographs are always nice to look at, but the added perlage, swirled graining, blued screws and interesting rotor make it all the better. One thing I was surprised by was that the Mühle rotor design is meant to have 5 small rivets, which weren’t present on the watch we received. Functionally, the MU 9408 is the same as the 7750, with 25 jewels, day/date, chronograph function, hacking seconds, hand winding, a 48hr power reserve and a frequency of 28,800 bph. It’s a great movement made even better, so you know it’s going to last. That said, we did notice the chronograph seconds had the occasional stutter, though that is likely atypical.

Straps and Wearability

The Terranaut I trail comes mounted on a 22mm black Russian leather strap with heavy white stitching and matching PVD buckle. It’s a very nicely made strap with a soft supple feel right out of the box. The design features a generous amount of padding by the lugs, which has a nice look and makes the strap more comfortable. The white stitching, though not bad looking, could have been more of a cream tone to bring out the khaki in the dial, but overall it works. One funny thing I noticed was that the strap that “new car” smell when I first took it out of the box…which I honestly really liked. Given the price of the watch, I would have liked to see a second strap option available, either a bracelet or something with more of an active sport material.


Naturally, the long lugs and pilot undertones make the Terranaut look great with NATO style straps. I threw one of our Gold NYC NATO’s with PVD hardware on there and it looked great. The yellow/khaki tones picked up the khaki in the dial while also adding contrast to the case, and the added bulk works well with the large case design.


The Terranaut wears well for a large watch, though it is perhaps too big for my 7″ wrist. The 44mm diameter is tempered by PVD, making it read smaller, though the 53mm lug to lug does span over my whole wrist. The 14mm height is very tolerable, which as I said earlier is made to feel thinner through smart case design. The look of the watch is simply great. It has an interesting aesthetic that speaks to military designs while having its own unique presence. The desire to make a sport watch intended for the trail comes through in the legibility and khaki on black colorway. Though the watch is available in PVD or stainless, the black case adds to the purposefulness of the overall design, as it clearly reflects less light.

As far as a daily watch goes, it certainly is robust enough to be a “go to” watch, though the aesthetics might limit its versatility. That is to say, not likely appropriate for dressy occasions, but suitable for casual to formal events. PVD is by nature less conservative, but I think with khaki pants and black shoes, this watch would look fine in an office. Of course, with black jeans and boots, this watch will look at home too.



One last thing worth mentioning is that the Terranaut I Trail comes in a beautiful wooden box. Made out of lacquered hardwood with a high gloss mahogany tone, this is the kind of box you’ll keep around. The outside is detailed with nice joinery and just a very high level of finish. The box opens by pushing on a metal button located on the lower half, which is a nice point of interaction. Inside you have your standard set up with a slot for the watch and a pocket for documents, all in a cream colored felt. All in all, just a great presentation.



Whether you intend on using the Terranaut I Trail for biking, hiking, other sport activities or just as watch with chronograph function, it will certainly be up to the task. The design is intriguing and fun, with an aesthetic that although familiar is unique enough to not feel derivative. The rotating triangle at 9 adds a lot of personality to the otherwise stern design, and is the kind of detail that can really sell the watch. The MU 9408 / Valjoux 7750 inside adds a dimension of fine mechanics that elevates the overall watch even more. It’s quite rare to find a chronograph at this price that has any in-house components, so that certainly is a great feature.

With that said, at about $3,335.00, the Terranaut I Trail is quite expensive and has tough competition. The movement modifications go a long way, but whether or not you wish to pay more for them is up to you. Clearly this isn’t a watch one buys on a whim, so the design really has to win you over. For me personally, though I love the looks, but the high price is very limiting. That said, the Terranaut series includes some much less expensive 3-hand watches, namely the 40mm Terranaut III, which at starting price of about $1,400 are much more tempting. Though the triangular seconds hand is unique to the chronograph, the three hands models speak to the land sport concept and have a nice and very clean design as well.

by Zach Weiss

Review unit supplied by Mühle Glashütte

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Zach is the Co-Founder and Executive Editor of Worn & Wound. Before diving headfirst into the world of watches, he spent his days as a product and graphic designer. Zach views watches as the perfect synergy of 2D and 3D design: the place where form, function, fashion and mechanical wonderment come together.
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3 responses to “Mühle Terranaut I Trail Review”

  1. Neil says:

    I love the looks and functions of the watch but why the puny 50m water resistance rating?
    I understand its not a diver so why not 100m or even 150m? In essence, what they saying is go ahead hike or climb that mountain, repel of that sheer rock face but be sure to take the watch off if your going to do the dishes. Seems to lose a bit of its punch, no? Another great review by the way.

  2. Toni says:

    Great review as usual. Just wondering, but if the purpose of the second dial is to show that the watch is running, perhaps it should have had some lume? It might be just me, but it reminds me of my water meter which has a triangle that indicates water is running through the pipes.

    I agree that the 50m rating doesn’t correspond to its “sports” persona – more like a dress watch rating.

    Lastly, I’m always wary of watch manufacturers having to dress up the presentation box to such an extent. Who’s got room for that kind of space waster.

  3. German Lopez says:

    I’ve really been digging these Mühle watches, especially The Seebataillon GMT. Very unique and different.