Exclusive: Dirt Rag test rides new prototype from Chris Currie and Speedgoat Cycles

Originally posted on April 15, 2015 at 20:36 pm

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If the name Chris Curries sounds familiar, it’s for good reason. The bike industry veteran owned Speedgoat Cycles, a Pennsylvania bike shop that grew into a major player. When he sold the company he moved to Portland to shepherd his Asylum brand. Now he is the creative director at Stan’s NoTubes. While he’s been a busy guy on the surface, he has also been working on a side project for almost a decade. Without any formal engineering background he set out to design a bike with 5 to 6 inches of travel that pedaled better than anything on the market. After a few false starts and some bumps along the way, he now has his first rideable prototypes. He offered Dirt Rag an exclusive first ride.

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The linkage shown here as 160 mm of travel moving through two counter-rotating linkages that rotate in sympathy (unlike the Santa Cruz VPP system) and they are designed to keep the instant center behind the bottom bracket shell, so that the rear end essentially rotates around its own center. “Picture the front triangle perfectly still, and points of the swingarm’s movement tracing a kind of perfect ‘bow-tie’ shape,” Currie explained. The upper cam link is really only necessary for fine tuning of leverage ratios, as they change as its shape changes. Currie says other versions of the design wouldn’t need it.

The axle path moves rearward for about 90 mm of the suspension’s travel, which Currie says is right on the sweet spot. Currie says the leverage rate follows a sine curve, almost like a VPP suspension, going from 2.55 to 2.46 to 2.6—a minor rising rate then a minor falling rate. Currie says he has it finishing with a falling rate to counteract the naturally occurring rising rate inherent in air shocks.

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“Marketing departments know to talk about ‘low initial leverage ratios for small bump compliance’ and ‘firm end stroke’ or whatever to prevent bottoming,” Currie says. “When what they mean is, ‘The bike bricks at only 80 mm, so we had to make it really soft at first, just to be able to get full travel.'”

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The design “sags into its travel really easily—you can stand next to it and push down to compress the suspension—but is actually using a mellow rising rate up to that first 90 mm of travel,” he explained “Once you’ve blown through 90-100 mm of travel, you’ve hit something that needs undivided attention, so the system switches to a mild falling rate. The overall result is really linear and creates that ability to pedal well while staying really supple, but the concept is kind of multi-stage.”

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Currie says another advantage of the design is its flexibility. He says it can be easily adapted to suit everything from a short-travel cross-country 29er to a downhill bike. The bike you see here is obviously just a prototype and far from being a finished product. Things like cable routing, bottom bracket height and fit are far from being ready for production. Currie says the next batch of prototypes will have a 66 degree head tube angle with a 160 mm fork, a 74 degree seat tube angle and 16.9-inch chainstays. The head tube will remain at 1.5 inches so owners can fine tune their geometry with an adjustable headset like the Cane Creek AngleSet. For now they also have 73mm threaded bottom brackets and 142×12 rear axles.

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A single ride isn’t enough to fully evaluate a bike’s performance, but it does help to get a sense of its personality. I took the prototype to one of my favorite local trails and despite not fitting on the size large very well, I immediately felt at home. The linkage design pedals extremely well, with almost zero bob even without the aid of a climbing switch on the RockShox Vivid Air shock. Initially set to about 25 percent sag I realized I wasn’t pushing it hard enough, so I was able to drop to 30 percent and still get the pedaling performance I was looking for while making the most out of the travel. While many pedal-friendly suspension designs lack small-bump sensitivity, this linkage has an almost uncanny ability to glide over small, square-edge bumps. I’m certainly not prepared to make a final judgement, but my initial impressions were positive.

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So what are Currie’s plans for the bike? Ultimately he is looking for a brand or group of investors to license the design, not unlike what Dave Weagle has done with his suspension layouts. Currie admits that launching his own bike brand around it would be a larger undertaking than he is interested in, but he plans to have bikes available as a demonstration of its merit. The Speedgoat name will stick around as his brand name, but not the name of the design itself.

Update: Here’s the second prototype that is being shown at Sea Otter:

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Stay tuned for more as we keep track of what’s next for Currie’s design.

 



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