Eclipse S11i

The Ultimate


We set out to build the ultimate in two-wheeled urban transport. No price point targets, no competitive analyses, no focus groups. Just a bunch of guys living in Taipei, Taiwan; Austin, Texas; Turku, Finland; Stuttgart, Germany; and Schaffhausen, Switzerland — otherwise known as the Tern product team — working together in the cloud and designing our collective dream bike for urban commuting.

Photo may show optional accessories.
N-Fold Technology

The Faster Fold

Folding bicycle design hasn’t changed much in decades. N-Fold Technology is a small but important change that results in a faster, and more compact fold. N-Fold Technology includes new frame and handlepost geometries and spins the front wheel by 180 degrees before the central fold, resulting in a package 40 mm (1.5”) shorter. Using N-Fold technology, our Eclipse and Castro bikes are only very slightly larger than the typical small wheel folding bicycle. Bicycles with N-Fold technology can also be folded – easily – in less than ten seconds.

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OCL Joint

Stronger, Better, State of the Art

The OCL Joint is a new reference in folding frame technology. It includes two new patents and everything we know about making the safest, strongest, and most durable frame joint.

  • Taller, Stronger, Stiffer — Making the hinge taller and moving the pivoting surfaces outward from the center axis more than doubles overall strength and stiffness and it’s a difference you’ll feel from your very first ride.

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3-D = Stronger

Folding bikes have a sometimes deserved reputation for flexy frames. All Tern frames feature patented DoubleTruss technology which turns the rear half of the frame into a three dimensional truss so that it’s much more resistant to torsional forces. That equals increased stiffness and much better power transfer from the pedals to the rear wheel.

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Smooth TIG Welding

Beauty Meets Function

The normal TIG welding process for aluminum bicycle frames is done by hand and involves the welder laying down a series of small, overlapping beads covering the two parts to be joined. The better the welder, the more uniform the beads. In the smooth TIG process, the welder makes a “double pass”, laying down a second layer of beads on top of the first. These beads are then sanded down by hand in an intensive process that requires extreme care. Done properly, the frame is strengthened because the possibility of stress risers is reduced. And the result is a very smooth weld joining the two tubes.

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Marco Dropouts

For the Right Amount of Adjustment

Proper chain tension on a hub gear in horizontal dropouts, when it’s also fitted with disc brakes, is an interesting engineering issue. We solved it with Marco dropouts, with integrated, adjustable chain tensioners and tunable disc caliper positioning. Custom CNC machined.

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Physis Handlepost

Stronger, Stiffer, Better Ride

Flexy handleposts and noodly handling are the Achilles heel of many folding bicycle designs. The Physis handlepost solves this with a massively strong, precision machined design that virtually eliminates flex. Four new patented technologies go into the design. The proof, of course, is in the ride.

  • Massive Strength — To eliminate flex, the Physis Joint knuckle was beefed up and made wider by moving the pivoting surfaces outward from the center axis.

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Andros Stem

Adjust to Fit

Your bike should adapt to your body and riding style, not the other way around. That’s why we developed the Andros, an adjustable stem that not only adjusts for height, but also reach. So whether you want your bars high and far, or low and close, the Andros will adapt. A single quick release controls both the stem and handlebar so it takes only seconds to get the bars in the position you want. The Andros features a patented TwinStem design, making it extra stiff and strong.

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Ergon BioKork Grips


Ergon grips deliver the ultimate in ergonomics for the hand, reducing fatigue and numbness, even on the longest rides. Ergon’s grips are made from a newly developed BioKork material using 40% cork, sourced from certified, sustainable forests in Portugal. In addition, the inner core is plastic reinforced using natural fibre, which makes up 40% of its mass. In place of mineral oil, the gel in the palm section of the grip is vegetable-oil based.

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Stasis Seatpost by Syntace

Ultra-light, ultra-tough

The Syntace P6 is one of the strongest and precisely engineered seatposts on the market. We wanted the best so we worked with Syntace to develop a 580 mm seat post with a variation of their 3D cold-forged P6 clamp. Made from ultra-light 7075 aluminum and hard-anodized (black color option) for scratch resistance. ERS technology delivers loads of fore/aft adjustment for the saddle: you can run the saddle forward for zero offset stiffness, or all the way back like an offset seatpost. Two bolt micro adjust for infinite angle adjustment.

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BioLogic Joule HG Dynamo Hub

The Holy Grail

HG stands for “Holy Grail” and that’s what this hub is to us. All of us here at Tern love dynamo hubs for their free electricity, but we hate the drag they add when we’re riding during the day and don’t need lighting. We’ve been dreaming for years about a dynamo hub that can be turned “on” when we need power, and “off”, with zero drag, when we don’t need it. Now we have it. The Joule HG has a switch on the side of the hub that can be rotated “on” and “off”. In the “on” position, the Joule HG is one of the most efficient hubs on the market.

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Shimano Alfine 11 Drivetrain

Shifting Refined

The Alfine 11 hub is a masterpiece of engineering. 11 evenly and widely spaced gears are enclosed in the rear hub shell and deliver 409% of total gear range. But the hub is much more than this: it’s also very light, coming in even lighter than the already svelte Alfine 8-speed hub, and special needle bearings are very low in rolling resistance. Shifts (with an XTR style trigger shifter) are butter smooth and can be initiated any time, while you are stomping on the pedals or while you are waiting for the light to turn green.

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BioLogic FreeDrive

Clean and Quiet

The BioLogic FreeDrive encloses the bicycle chain to keep the rider’s clothing protected from grease and dirty spray. The FreeDrive’s ingenious design moves with the chain so it is friction free, unlike with some other chain protection methods. It also reduces chain vibration and noise. With a FreeDrive, you can say goodbye to bulky chainguards and enjoy the looks and cleanliness of a belt drive with the efficiency of a chain drive.

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Luggage Socket

Carry More Stuff

When you need to carry more stuff on your bike, just plug the optional Luggage Truss into the Luggage Socket that’s welded to the head tube of every Tern bike. The Luggage Truss works with any bag, basket, or rack with a KLICKfix adapter. The benefit of a frame mounted luggage system (as opposed to fork or handlebar mounted) is that it doesn’t adversely affect steering. Available Tern accessories include: Kanga Rack, Tour Bag, and CarryAll Basket.

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Valo Light

Integrated Lighting

The Valo is a front light designed specifically for integration with the Andros stem. The Valo snuggles into the space between the Andros’ twin stems, so it’s nice and protected. The high output LED casts a bright, white light for evening rides. The Valo comes in two versions: dynamo with StandLight function and battery. If you do go with the battery version, we recommend rechargeables.

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Tern Tail Masked Paint

Super-fine Details

Getting this finish just right needed a LOT of work with our paint factory. It basically involves incredibly meticulous hand-masking to achieve the final result. With the silver/black finish, we hand-polish the aluminum frame to a mirror finish and then follow that with hand-masked black paint. Detail: the shape of a Tern’s tail is echoed in the paint masking.

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General Info
Wheel Size: 24 inch wheels
Speeds: 11
Weight: 14.7 kg
Folding Time: 10 sec
Folding Size: 42 x 89 x 76 cm
Frame Sizes: One size
Gear Inches: 30" - 120"
Distance: Seatpost to Handlebar: Min: 57 cm Max: 73 cm
Distance: Saddle to Pedal: Min: 75,5 cm Max: 103 cm
Suggested Rider Height: 148 - 195 cm
Max Rider Weight: 115 kg
Frame: Eclipse, hydroformed 7005-AL w/ smooth TIG welding, patented OCL Joint and DoubleTruss technology
Fork: Aero, aluminum, 6061-AL
Handlepost: Physis T-Bar, 2D forged aluminum, 4 patented technologies
Stem: Andros, 3Djust technology, Norglide bearings
Headset: Flux Pro, angular contact cartridge bearings, Tri-seal technology, machined aluminum cups
Handlebar: Kinetix Pro, double-butted 7050-AL, for VRO
Grip/Bars Tape: Ergon GP1 BioKork
Saddle: Kore Sola for Tern, hollow cro-mo rails
Seatpost: Stasis by Syntace, 7050-AL
Seatpost Clamp: Syntace, stainless bushing
Front Brake: Avid Elixir
Rear Brake: Avid Elixir
Brake Levers: Avid Elixir
Brake Cable & Housing: Avid Elixir
Front Hub: BioLogic Joule HG, disc
Rear Hub: Shimano Alfine, 11-speed
Spokes and Nipples: Double-butted 18/10 stainless, Sapim Polyax nipples
Rims: Kinetix Pro, niobium alloy, mirror finish
Tires: Big Apple 50-507, 70 psi, RaceGuard puncture protection
Shifter(s): Shimano Alfine, 11 spd.
Crankset: FSA Vero, ISIS BB, CNC Guard
Cassette/Freewheel: Shimano for hub gear
Bottom Bracket: American Classic, ISIS
Chain: RustBlock, GST coated, 3/32"
Pedals: MKS EZY QR
Shifter Cable & Housing: Shimano
Chainguard: BioLogic FreeDrive
Kickstand: Premium single, aluminum
Clip System: Magnetix 2.0
Luggage Socket: Yes
Front Light: Valo, HiLux LED with StandLight
Rear Light: Spanninga Premium, LED
Fenders: SKS, stainless hardware
Rack(s): BioLogic Portage Racks
Headset Press
November 15, 2012

"The Eclipse P7i is easily a very good contender for a practical bike. We at Headset Press really like the look of Tern’s, coming in good colours and generally well styled (not common for folding bikes!). They pay a lot of attention to the aesthetic of their bikes and it really shows. So if you’re in the market for a folder or solid commuter bike look no further than Tern."

Read the entire article online here.

Folding Bikes
October 16, 2012

"Overall, the Tern Eclipse P9 folding bicycle rides like a dream on the street, with the 24” wheels rolling over the bumps and crevices with ease. With its range of gears you’ll be able to ride up bridges and hills during your commute, or carry some groceries home from the store. At the end of your ride, fold up the bike and stow it away. The Tern Eclipse is a great blend of comfort and portability."

Read the full article online here.
July 2, 2012

"And when it comes to handling, the Eclipse S11i is on a class of its own. The bike’s Andros steering system is solid and responsive. I tried the bike on three different kinds of riding: short and middle distance commutes, long-distance day tour – and I am happy to report that all had turned out really smooth."

Read the full article online here.

June 29, 2012

"Das Tern ist die eierlegende Wollmilchsau, die sich wirklich fährt wie ein großes Rad. Größere Laufräder und ein etwas größeres Faltmaß bringen beim Tern ein vielfaches an Fahrfreude an einem rundum gelungenen Rad. RADtouren Kauftipp!"

June 27, 2012

"Was die Eclipse-Serie von Tern auszeichnet, ist unseres Erachtens vor allem das Fahrverhalten: Die um zehn Zentimeter größeren Durchmesser im Vergleich zu den üblichen 20 Zoll-Rädern stabilisieren durch ihre höheren Kreiselkräfte die Fahrt, sie loten mit ihrem größeren Radius nicht jede Plattenfuge aus, und sie verkürzen Dank des höheren Rahmens den Überstand von Sattelstütze und Lenksäule. Diese werden dadurch wesentlich steifer. Zudem hat Tern gegenüber früheren Dahon-Modellen die Rahmen komplett überarbeitet und mit deutlich größeren Faltscharnieren versehen. Wiegetritt, einhändiges oder gar freihändiges Fahren – unterm Strich fährt sich das Eclipse P9 fast so, als sei es kein Faltrad."

The active Times BETA
May 18, 2012

"The Tern’s larger wheels and stout frame take it in stride, and feel quite comfortable at speed, too. The double-braced, fully adjustable stem, in particular, gave this bike the most assured front-end stiffness of the bunch — plus it’s a great feature for fitting riders of varying sizes."

Read the full article online here.

April 16, 2012

"The Tern Eclipse S11i is one of the most well conceived folding bicycles from Tern. It has more features than any other Tern bike: dynamo lights, hydraulic disc brakes, rack, fenders, adjustable handlebar, and the list goes on! If you want the best of the best folding bikes from Tern the Eclipse S11i is the one for you."

Watch the full video review of the Eclipse S11i.

The Gear Caster
November 5, 2011

"So you got a folding bike, you can just go in (to the ferry) and sit down. So while everybody kinda has their bikes deck on each other. You can just hang out and have your bike next to you for the next ride. This is pretty cool."

Read the full article online here.

RADtouren Magazin
October 18, 2011

"Ebenfalls auf der Eurobike nahm die Redaktion des Magazins RADtouren auf dem 24″ TERN Eclipse S11i Platz. Das überaus positive Fazit des Kurz-Checks."