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1. Kestrel introduced bladder-molded monocoque carbon structures to the industry in 1986. Carbon fiber composites delivered the best of all worlds – stiffness, strength, lightweight, formability, corrosion resistance, shock damping – for a superior ride. The use of Aerospace-grade carbon/epoxy “pre-preg” materials would revolutionize bicycle frame design and manufacturing and change the sport forever.

2. Our Modular Monocoque construction combines the best of the multi-patented Kestrel frame technologies, EMS fork technologies and structural bonding techniques that we’ve honed for two decades. A one-piece, hollow bladder-molded main frame is joined to separately bladder-molded rear sub-assemblies using advanced bonded joint designs and aerospace adhesives, yielding a single Modular Monocoque frame structure.
[ref “why kestrel” info on website]

3. Kestrel was the first company to use higher-stiffness “intermediate modulus” carbon fiber, dating back to 1989 and the 200 EMS. In fact, Kestrel’s use of Hercules “IM-8” fiber pre-dated the US Air Force’s qualification for the F-22 Raptor prototypes by two years.

4. Kestrel introduced the world’s first all-carbon composite bike frame, the Kestrel 4000, in 1986 for the 1987 model year. The 4000 was also the first production frame with aerodynamic “tube” sections.

5. Kestrel was the first bicycle company to employ true aerospace carbon fiber engineers, starting back in 1986, with engineers from such companies as Lockheed Missiles & Space, Aerojet Strategic Propulsion and the US Air Force Advanced Composites Program. The original Rocket Scientists of the bike industry.

6. Kestrel engineers have set up carbon fiber frame manufacturing plants in the US (three separate facilities), Japan and China. We have acted as consultants on manufacturing equipment, processes and quality control to today’s major Asian carbon frame suppliers. We’ve been there and done that so we know exactly what it takes; and we know exactly what to monitor to insure that Kestrel’s strict engineering and quality standards are met.

7. Kestrel introduced the world’s first all-carbon mountain bike, the MX-Z, in 1988. This bike dispelled the myth that carbon fiber composites could not stand up to off-road use and abuse.

8. Kestrel introduced the world’s first all-carbon triathlon bike, KM40, in 1989. One of the first bikes to adopt a forward, 78-degree seat position and dual 650C wheels, the KM40 also was the first production “tri bike” to utilize aerodynamic tube sections.

9. Even Kestrel’s owner/operators are aerospace-trained carbon fiber engineers, including its President and its Product & Marketing Director. These two individuals alone represent more than 40 years of carbon fiber engineering in both design and manufacturing.

10. Kestrel provides design and manufacturing engineering to several automotive aftermarket companies.

11. World’s first monocoque carbon road fork, the “EMS Fork”, introduced for 1989. With its higher stiffness, lower weight and smoother ride over the existing metal forks, the EMS literally created a new market segment. Carbon forks are now standard spec on virtually every high-end road and tri bike.

12. Kestrel’s full-carbon “Nitro” MTB prototype of 1988 was the predecessor to the full-suspension craze. The bike featured the first-seen prototype of what was to become RockShox, as well as ingenious approaches to high-forward pivot design, linear-pull brakes and on-the-fly suspension lockout. In 2001, the Nitro was selected by Mountain Bike magazine as the second most important mountain bike – ever.

13. 1992 – the Kestrel 500 SCi is the first modern seat-tubeless design. Kestrel engineers fully exploit the unique properties and formability of carbon fiber, creating a structure completely unattainable with traditional metal frame materials and providing improved aerodynamics, a silky-smooth “passive suspension” ride and stiffer-than-steel bottom bracket response.

14. The 1999 KM40 Airfoil becomes the first molded composite frame completely designed utilizing 3-D Solid Modeling techniques. Kestrel’s advanced design is so complicated in form that not even the engineers who developed the Solid Modeling software can replicate it. Instead, custom-modified code must be used to input the KM40’s complex curves and blends.

15. Aluminum rivnuts, stainless rivets. There you have it, the entire list of “off the shelf” items that go into a Kestrel frame. Because every Kestrel – road, mountain or tri – is designed entirely from scratch by our team of engineers and designers, from the proprietary modular monocoque composite structure to the model-exclusive machined, stamped or forged details that finish it off. Unlike our competition, we don’t use any pre-made, generic-design tubesets, stay assemblies, or metal fitments.

16. No generic “private labeled” forks, either. Every Kestrel road and tri frame comes with its own model- and size-specific Kestrel fork design, based on over 17 years of experience in making the finest carbon forks available.

17. Proprietary Bonding Design and Techniques. In addition to our pioneering development of monocoque carbon molding, Kestrel has employed engineering-grade structural adhesives and bonded joint designs since day one. We design our bonds correctly, loading the adhesive in “shear” for optimal strength, with properly maintained adhesive gap for reliability. Typically, the bond is over-designed so that its strength surpasses that of the carbon structure itself. It’s light-years from gluing a bunch of separate tubes and lugs together.

18. Even our bonding adhesive is better than what the other guys use. While others specify a cheaper, quick-cure single stage glue, Kestrel engineers insist on using the highest quality, aerospace grade 2-part structural epoxy adhesive. This adds time – and cost – to our manufacturing process, but it also provides the strongest bonds possible. We wouldn’t have it any other way.

19. Every Kestrel carbon fiber frame, fork, handlebar and seatpost is covered by our legendary Lifetime and No-Fault Warranties.
[ref “warranty statement” on website]

20. All Kestrel frames, forks and components are built using unidirectional, long-filament pre-preg composites. We use long-filament 700K and 800K carbon for the superior strength you get from continuous fiber runs, and we can tune each structure with careful fiber orientation. Our pre-preg carbon - meaning it's pre-impregnated with resin - uses a proprietary, toughened thermoset resin matrix. A fancy way of saying we employ a tough, strong epoxy to hold our carbon together. By using pre-pregs we're able to ensure an optimal fiber-to-resin ratio in the completed part, what you'd call lightest and strongest. This is the preferred way of building carbon parts, that’s why it's employed in Aerospace, Formula 1 racing and virtually all other high-performance applications.

21. Carbon fiber has the best stiffness-to-weight and strength-to-weight ratios of any frame material, with infinite fatigue life and a shock-damping capability 10-15 times that of metals. But not all carbon is the same - there are different grades of carbon, just as there are different grades of metals. We use two different grades of carbon fiber, 700K and 800K. The "K" is short for ksi, which denotes the material's tensile strength in thousands of pounds per square inch. So 700K carbon can withstand a tensile load of roughly 700,000 pounds per square inch of material. And 800K is even stronger, taking an 800,000-pound load. For comparison: chrome-moly steel falls into the 63-97 ksi range, 3Al/2.5V titanium is 73-90 ksi, 6Al/4V titanium is 128-138 ksi, 6061-T6 aluminum is 40/45 ksi, and 7075-T6 aluminum is 73-83 ksi.

But even more significant is stiffness, since a stiff frame that resists pedaling forces is a more efficient one. Carbon's stiffness trumps other frame materials, hands down. Our 700K carbon has a relative stiffness (or Elastic Modulus) of 33.4 million pounds/square inch (msi), and the 800K fiber we use is 42.7msi. (Chrome-moly steel, the stiffest metal used in bicycle frames, comes in at 29.7 msi, 3Al/2.5V titanium is 14.5 msi, 6Al/4V titanium is 16.5 msi, while 6061-T6 and 7075-T6 aluminum are 10.0 and 10.4 msi, respectively.)
[ref “About Carbon” page of our Technology section]

22. Carbon composites offer 10-15 times the shock-damping capabilities of any of the metal frame materials. Which means that, unlike with metals, you actually can feel the difference. With metal structures, the only way to absorb road shock (without incorporating suspension devices) is through flex, so comfort and efficiency become polar opposites. With carbon fiber composites, the inherent damping of the material is substantial enough that the comfort of the frame can actually be addressed separately from its structural performance. The result – a strong, stiff Kestrel frame or component that provides an incredibly efficient ride, yet smoothes out the road and tracks like nothing else.

23. Optimized Tube Shapes and Junction Design. Everything on a Kestrel frame is designed for optimal performance of the task at hand. Tubes and junctions are sized and shaped for the given loading conditions and functional requirements. Tube sizes and shapes continuously vary from one end to the other; bottom bracket and head tube areas are massively reinforced; stays are formed to provide tremendous lateral stiffness while adding to the signature smooth ride.

24. Size-Specific Structural Design and Fiber Layup. Kestrel engineers vary the type, amount and ply angles of our carbon fiber pre-preg materials throughout each frame design, to suit the structural needs at literally every point in the frame. This maximizes performance and ride quality while eliminating unnecessary weight, regardless of frame size. Plus, tube and junction sizes are actually designed in proportion to each individual frame size for consistent stiffness, response and ride throughout the line. In fact, in some models every tube and junction is scaled proportionally to every frame size.

25. Ride Tuned Stays. Our Modular Monocoque seatstay and chainstay sections are engineered for efficient power transfer and lateral tracking, while at the same time enhancing the already silky-smooth carbon ride. Hollow, bladder-molded stay assemblies combine the best of Kestrel frame, fork and bonding technologies. Add to this design details such as functional aerodynamics, and our size-proportional sections and fiber layup techniques.

26. Exclusive and Proprietary EMS Fork Technology. Every Kestrel road and tri model frame comes with its own design-specific Kestrel fork. Each is designed and manufactured using our legendary and proprietary “EMS” fork technology and, like our frames, held to the highest engineering, quality and reliability standards in the industry. Every aspect – from materials and processes, to geometry and functional styling, to performance and ride quality – is designed to work in concert with and enhance the Kestrel frame.

27. Proven No-Compromise Geometry and Fit. Kestrel road, mountain and tri geometries have been tweaked and refined over two decades, with input from some of the premier sizing and fit experts in the industry. Geometries are based on classic center-to-center dimensions - we don’t compromise with one-size-fits-all designs or marketing fads. And since each size of each frame model requires its own unique set of costly CNC-machined tooling, the geometry spec’s for each size can be designed without the shared tube angles, lengths or junctions commonly found on volume manufacturers’ frames. As a result, Kestrel frame models provide size-proportional fit and consistent performance throughout the range.

28. Every millimeter of the Airfoil Pro tri bike is designed to minimize drag and provide high-speed stability. Case in point: Our engineers employ extensive wind-tunnel test knowledge to push the aerodynamic “center of pressure” as far rearward as possible. This precise redistribution of side surface area maximizes crosswind stability, plus it reduces drag by taking full advantage of the forward lift vector generated by those same crosswinds.
So the only ones being blown away are your competitors …

29. The 2006 Airfoil Pro combines exacting new carbon/epoxy materials processing with fine-tuned ply orientation for increased torsional stiffness and bottom bracket rigidity. The result – a faster, more efficient bike that retains its signature smooth ride and wind-cheating performance.

30. Kestrel wrote the industry handbook on carbon bicycle design, and our engineers are constantly adding new chapters.

31. Kestrel introduced the world’s first one-piece molded carbon road handlebars, the “EMS Pro” series, in 2001. Lighter and stiffer the then-standard aluminum bars, with a smoother ride, an unlimited fatigue life and a Lifetime Warranty.

32. Every tube and stay on the Evoke features unique, continuously varying cross-sections over its entire length, for optimal use of our proprietary 700K Carbon Fiber. Kestrel engineers employ 3-D Solid Modeling software to develop each size’s proportionally scaled tube and junction profiles, for consistently superior stiffness, response and ride quality throughout the size range.

33. Every Kestrel design is proprietary-we engineer everything in-house in Santa Cruz, California, beginning with computer-aided design & analysis and ending with exacting manufacturing procedures and quality standards. While other companies may simply order up a mass-produced, generic-design carbon frame from a nameless factory and slap their own stickers and paint on it, we engineer every Kestrel from scratch.

34. Ever notice how some of our competition’s bikes look like Kestrel designs of ten or more years ago? We have…

35. Kestrel Engineering specifies the most rigorous qualification testing of carbon products in the bicycle industry. Twenty years of prototyping, manufacturing and testing of carbon frames, forks and components gives us a proprietary database that has proven effective time and again. While other companies rely solely on certain commonly accepted “standards” as well as the advice of their outside suppliers, Kestrel goes the extra mile to consistently produce the most reliable, best performing products on the market. Yes, it’s more costly to produce products that satisfy our testing requirements, but we believe it’s a better value at the end of the day.

36. Fiber Areal Weight (faw) – is the weight of the fiber portion of a given quantity of fiber/matrix pre-preg material; usually expressed in grams-per-square meter, or gsm. For example, a carbon/epoxy pre-preg with a faw of 150 gsm contains 150 grams of carbon for every square meter of material. Similarly, one square meter of 110 gsm material would contain 110 grams of carbon. Since the comparative surface area is fixed (one square meter) the difference in fiber weight will determine the thickness of the layer, or “ply” of pre-preg material. Note that faw has nothing to do with the stiffness or strength properties of the material, but is merely an indication of the fiber weight and therefore the ply thickness of the material.

Lowering the faw of a given fiber will make the ply thinner and lighter, but will also decrease the structural properties. However, when employing a stronger, stiffer material - such as Kestrel’s 800K carbon - the faw can be reduced proportionally to provide a thinner, lighter structure while retaining sufficient stiffness and strength in the final structure.

In fact, Kestrel was the first to combine a lower faw with higher grade, high strength/high stiffness fibers to produce ultralight carbon frames, starting with the 200 EMS back in 1989. Years before the industry marketing machines caught on to this concept.

37. The Airfoil Pro comes in a full range of six sizes – from 47cm to 59cm, to fit a wide range of athletes. Yet each and every size features its own unique set of geometry and fit specifications. Head angles and seat angles are dialed to the nearest quarter-degree, to provide consistently superior fit and finely balanced handling throughout the range. Even wheel diameters are proportional, with 700C wheels on 54/56/59cm frames and 650C on 47/50/52cm versions. So you get the best fit and fastest ride possible, regardless of your frame size.

38. The Evoke comes in a full range of seven sizes – from 47cm to 62cm. Yet each and every size features its own unique set of geometry and fit specifications. Head angles and seat angles are tweaked to the nearest quarter-degree, to provide consistently superior fit and finely balanced handling throughout the range. We don't cut corners to save in tooling or production costs. So you get the best ride possible, regardless of what size frame you ride.

MORE TECHNOLOGY:
Production Perfection | No-Compromise Materials | About Carbon | Anatomy of a Kestrel

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