Linkage suspension forks aren't a new concept, with the idea being trailed in all sorts of two-wheeled sports throughout the past. Fans of motorcycle road racing still talk about the legendary ELF Honda NSR500 and its wild chassis and linkage front-end that was raced in the 1980s, and mountain biking has also seen a handful of different linkage forks over the decades, from AMP to Whyte and a few others. None of those designs ever caught on, however, and traditional bushing-based suspension forks are obviously still the norm... but should they be?
Structure Cycleworks wants to change that with the 150mm-travel SCW-1 and their linkage fork that's integrated into the bike's carbon fiber chassis. The company knows that they're going to have an uphill battle and that the bike's polarizing looks will be an instant turn-off for many riders, but Structure Cycleworks' Loni Hull says that they're aiming to win people over with its performance, not its appearance.
The blue bike in the Structure Cycleworks booth is a rapid prototype model that hints at what their production version might look like.
What are the claimed performance advantages over a telescoping fork? We've come to accept that telescopic forks have a large amount of inherent friction, even if they feel smooth, and linkage designs have been proven to be nearly friction-free thanks to the sealed bearings that they pivot on. Less plain to see, though, is the ability to tune both the axle path and the amount of anti-dive, which means that the bike could be designed to handle much more consistently. That should add up to more control, confidence, and speed - at least in theory.
But even if those claims all ring true, the trick might be to convince the everyday rider that this wild looking machine is worth considering. As much as some of us get excited about gear that has the potential to be better, we're a weird bunch that rarely embrace disruptive ideas from way out in left field.
My test bike was built three years ago as a proof of concept.
The Structure Cycleworks bike and linkage fork are from well outside the stadium compared to what we're used to; not just left field. Part of the issue for what will surely be a lack of universal acceptance is that it's not like the latest suspension from RockShox, Fox, et all performs poorly, is it? No, of course not, but Structure Cycleworks' Loni Hull believes that it's going to take a paradigm shift in order for suspension performance to take another substantial leap forward.
''There's only so much we can do to make forks maybe only a little bit better for next year, but it's all incremental improvement from maximum effort,'' Hull told me when I posed the simple question of why. ''We're designing with a clean sheet; we're looking at how to make a bike ride better for a rider. It performs well enough that I feel there will be a market for it with people who want something that's a quantum leap over the best of what's currently available in enduro,'' Hull went on to say, clearly not short of confidence in the design.
Loni Hull poses with the rapid prototype model.
The linkage design activates a RockShox damper to deliver 115mm of travel. The production version will have 150mm, however.
Hull explained that the most notable advantage to their linkage system was that the bike's front-center length actually grows longer as the fork goes through its travel, which is the exact opposite of what happens with a traditional suspension fork that shortens the bike's front-end and steepens the head angle when it compresses.
The Structure Cycleworks linkage design actually lengthens and slackens the bike's front-end by as much as a whopping eight-degrees for their 150mm-travel fork, and by about five-degrees for the 115mm-travel fork that I briefly rode. Why would this be a good thing? Getting the front wheel farther out in front of the rider, especially when the fork is deep into its travel, is only going to add stability and keep the rider from feeling like they're about to get chucked over the handlebar.
Even if it performs better than a traditional fork, will mountain bikers be able to get past the appearance?
Right now, a fast and aggressive rider often has to over-pressurize their fork's air-spring if they're facing a steep or rowdy trail, something that compromises small bump action. If the Structure Cycleworks linkage fork performs as claimed, a rider shouldn't have to make this concession. ''We take a rider's center of mass and we look at how the kinematics move around that center of mass,'' Hull explained. ''What we decided is that we didn't want a force-path that brought the axle in a kind of J-hook pattern; we wanted one that maintained the front-center and came up more vertically before it starts to go back into a slacker angle for the big hits.''
That's plenty of talking, but the truth will only come out on the trail, so that's where I went. The futuristic looking blue bike in the Structure Cycleworks booth is actually an unrideable rapid prototype, but they did have their older proof-of-concept machine on hand that they let me take out. This bike is unapologetically rough - it was created three years ago purely to prove that their system has potential. So off I went to find out how much potential it has.
The prototype bike has 115mm of travel up front but it feels like more. And yes, that is a highly modified Norco rear-end you see.
My three-year-old test bike had some fairly dated geometry and a long-ish stem, but you know what? The damn thing felt like a mountain bike to me, and I mean that in the best way possible. The 115mm-travel linkage fork definitely did not feel like a normal fork, though; it was impossibly active relative to how much travel it has.
I'd go so far as to say that it was more supple than the newest 150mm-travel forks on the market, enough so that I first suspected an under inflated front tire, which wasn't the case. I spend a lot of my time on 120mm-travel suspension forks and none of them are anywhere near as active as this odd looking linkage contraption.
The fork was impressively supple, far more than a standard short-travel fork.
My other thought was that the bikes front end felt very torsionally rigid. Yes, at well under 160lbs I don't exactly find any fork to be all that noodly, but it was quickly obvious that the Structure Cycleworks front-end doesn't flex as much as a traditional fork that depends on its axle and arch for rigidity. The linkage fork that I rode is over three years old, and it's little RockShox damper sees too much leverage, but the action was still impressive and, most importantly, very controlled feeling.
In fact, if it was somehow possible to do a blind test without me smoking a tree head on, I'd likely get off the bike saying that it's running some sort of high-end, 150mm-travel fork, which is quite the praise considering that it's actually a three-year-old design with an over-leveraged damper and just 115mm of stroke.
It looks different, but the prototype performs well enough that I'm looking forward to trying the new version.
What good is a test ride if you don't actually test the bike? Getting airborne on the prototype.
So, is this the future? Yes and no. I believe that a linkage design does offer some substantial performance advantages over what we're all using now, especially in a long-travel setup. And Hull is also likely correct when he says that the paradigm shift of a proper linkage fork is the only way to get more than a few percent performance jump over today's high-end forks. But even if all that does end up ringing true, I just don't see the majority of mountain bikers being all that accepting of the design.
The Structure Cycleworks bike is just too disruptive, too out there to become the norm, and there has been of decades of development and acceptance of traditional suspension forks. Regardless of those facts, I won't be the least bit surprised if and when the 150mm-travel SCW-1 comes out and really does blow current bikes and suspension forks away.