SilkTi Technology:
Although simple in appearance, the Ibis SilkTi is a marvel of technology and clever engineering. The sections below summarize the design goals and features found on the patent pending SilkTi. Each links to a more technical description of what technology was used to accomplish our goals.
SilkTi Design Goal
Our Goals for the SilkTi are simple yet lofty: To keep the simplicity, light weight and aesthetics of the softtail, while engineering more rigidity and travel into it. Like all our suspension bikes, we insist on the highest quality travel with maximum pedaling efficiency, resulting in more plush with less mush. We've always been taught to think for ourselves. For example, we came up with the Ti Mojo using the world's first truly double butted titanium tubeset, and then the still unreplicated BowTi, a bike Mountain Bike Action calls "the world's most fabulous dual suspension bike". Continuing to think for ourselves and wanting to disprove that adage that "you can't please all the people all the time", we felt compelled to invent the SilkTi, a short travel bike completing our Holy Trinity of hardtail, softtail, and full-suspension titanium frames. You can call the SilkTi a short-travel pivotless frame, or more simply a softtail.
Softtails are usually light and simple, but we wanted to get more than the typical one-inch or less of suspension travel, and we wanted a true full-suspension feel. Other softtails are all minor variations on common themes; round chainstays and short-travel shock absorbers. Thus they all suffer from the same problems: limited vertical travel, insufficient lateral rigidity, and poor performance. Our Patent Pending chainstay and CDE shock absorber solve these problems to give you more lateral stiffness and more high-quality travel than any other softtail.
These solutions are simple, effective, durable and lightweight.
The Chainstay
The SilkTi chainstay is the most striking feature of the frame. It is a fully triangulated _" tall plate of Ti 6Al/4V, known to engineers as a planar truss. We went with the flat plate because we wanted a part that is flexible in the vertical direction and stiff laterally. Round tubes are only capable of very limited travel, and tend to make the rear end whippy, which are symptoms common to softtails. Our plate chainstay is the cure. The chainstay is ten times as flexible vertically as it is laterally, compared to a round tube which is the same stiffness in both directions. We've prepared a technical section complete with an animation showing the stress analysis on the part.
Click here to learn more >
See an animation of the silkti chainstay in action >
The CDE Shock
CDE stands for critically damped elastomer. Usually, damping is not associated with elastomer shocks. But ours is different from others, providing damping in proportion to the size of the bump. Most softtails use a coil spring as a shock. The problem with a coil spring, aside from excess weight, is that the stiffness does not increase as it is compressed--it's not progressive. A suspension designer using a coil spring on a short-travel bike has to make serious compromises. A coil spring must be stiff to avoid harsh bottoming, but then it's too stiff to absorb even small bumps well. So it doesn't work well on big bumps because of limited travel, or on small bumps because it's too stiff. Sometimes a small elastomer is used inside the coil to keep it from bottoming harshly. This helps, but still, a coil is not as smooth as a pure elastomer spring. Our CDE shock provides a solution for all of these shortcomings.
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The Rest of the Frame
Unfortunately, a frame is only as stiff as its flexiest link. We quickly noticed that many softtails have too much flex in the front triangle, so we've redesigned the front of the bike to solve this problem. On the computer, John tweaked the diameter and wall thickness of the tubes to evaluate each one's effect on front triangle stiffness. This let him hone in quickly on the optimum combination. You'll notice that the SilkTi has a special large diameter downtube and toptube, which will give us an impressive 38% increase in front end stiffness over a normal size tube. This makes the overall stiffness as good as our benchmark which just happens to be one of our other favorite bikes-the Ibis Ti Mojo.
