Hi from Structure Cycleworks and thanks for taking an interest in our upcoming SCW 1!
It's weird. We know. But it's not different for novelty value. Linkages allow us to do things that simply can't be done with a fork that's constrained to moving in a straight line. We're pretty fond of our bike and here's why we think it may finally be the one to realize the potential of a front linkage:
There are six primary performance benefits to Structure's WTF (Without Telescoping Fork
) suspension design, which also highlight some of the things we're doing differently from past designs. For consistency, the following points refer to heave compression (equal front and rear suspension compression), relative to a traditional, telescoping fork (and previous bicycle linkage front suspension, where noted):
- A combination of two properties that we call "Stability on Demand":
- The head angle becomes slacker as the suspension compresses, maximizing handling agility in less demanding situations, such as riding uphill, and increasing stability in demanding situations. No other production bicycle suspension has done this (certainly not to any significant extent).
- The trail increases as the suspension compresses, again maximizing handling agility in less demanding situations, such as riding uphill, and increasing stability in demanding situations.
- Brake dive is reduced, minimizing load transfer, improving chassis stability, and retaining positive suspension travel when braking. The balance between anti-dive and compliance has taken a large portion of our R&D time and we offer four settings to allow riders to dial it in to their liking.
- The motion ratio and motion ratio curves of the front and rear suspension are matched for optimal suspension balance and increased predictability of the chassis for the rider. No other suspension system has done this.
- Optimized pivots:
- Linkage elements rotate on ball bearings, rather than sliding bushings, which reduces friction in the system and improves suspension compliance, particularly on small impacts.
- The WTF design does not use spherical bearings in the structural elements of the suspension, only in the steering links. Spherical bearings have been a weak point of some previous front linkage designs.
- The linkage elements are integrated into the chassis, rather than being a stand-alone component that mounts to the head tube in the traditional manner. This allows the linkage arms to be longer, reduces the length of highly stressed chassis elements, and distributes loads more evenly throughout the chassis.
- The linkage control arms, when taken together, are the longest ever used in a production bike application. Longer arms permit more consistent chassis dynamics throughout the range of suspension travel by reducing the change in instant centre location and motion ratio.
Four other important differences between Structure's design and that of other bikes:
- SSK (Size-Specific Kinematics): Each chassis size features a unique location of each pivot to ensure the suspension dynamics remain consistent for all rider and chassis sizes.
- Gravity Sizing: Customizable seat tube lengths to allow riders of various heights to choose a chassis size based on desired handling characteristics, rather than rider leg length.
- Wide Range Geometry: Bikes without variable seat tube length are forced to offer an excessive number of frame sizes with little difference between each size. By separating seat tube length from chassis length, Structure can offer meaningful differences in handling properties between each size and span a range of rider agility vs. stability preferences.
- The modular nature of the front-end components (steering links, upper crown, lower headstock) facilitate custom parts for geometry and handing modifications if demand arises.
I'll address some of the other questions and ... "suggestions" raised in this thread. After that, I'll try to monitor this thread (if anyone is still reading it), but the best way to reach me is at Ryan at Structure dot bike.
Thanks to everyone here for taking an interest in unconventional designs and doubly so to those who keep an open mind!
-Ryan