On September 29, 2023 US patent number 7128329 is set to expire. While few outside of the mountain bike design world know this patent by number, consumers are likely familiar with its street name: DW-Link. Designer and engineer Dave Weagle patented the highly regarded suspension design in 2003, and this year marks its 20th anniversary. It also marks the end of US patent protection for DW-Link.
What is the DW-Link?
Few mountain bike suspension designs have been referenced more than number 7128329, with dozens of subsequent patents from brands including Yeti, Santa Cruz, and Knolly seeking to improve and build upon, or at least differentiate themselves from, patent number 7128329.
While a total of five brands licensed DW-Link back when it was new, two are still using the design today, and with no shortage of success. Ibis and Pivot Cycles have both taken DW-Link to new heights and used the linkage to build global brands. Iron Horse, Independent Fabrication, and Turner Bikes also licensed the design in the past. Iron Horse dissolved after filing for bankruptcy in 2009, Turner moved to rigid titanium frames, and Independent also stopped pursuing linkage bikes.
The patent’s abstract explains DW-Link is “a wheel suspension system having, under powered acceleration, a squat response that begins in the realm of anti squat and passes through a point of lessened anti squat at a further point in the travel.” It then goes on to explain the physics of the system in detail over the course of more than 12,000 words.
Though it’s likely been a while since the website was updated, DW-Link.com lays out seven reasons why the design is the “best performing suspension system in the bicycle world” in terms a little easier to comprehend than the patent language.
The design is efficient and deals with anti-squat, or the tendency for weight to shift rearward when a vehicle accelerates; DW-Link reduces pedal feedback during suspension compression and doesn’t lock up under hard braking, keeping the wheel on the ground; the suspension system also had a more advanced leverage curve than others at the time of its patent and didn’t need to rely solely on a shock damper to control its travel; and, because of the platform’s short suspension links, the rear triangles on DW-Link bikes could remain in one piece, increasing stiffness that is often lost through longer links or pivots built into the chain or seat stays.
Ibis and Weagle began working together in 2005, after the bike brand’s “re-birth,” which brought their first carbon full-suspension bike the Mojo, built around the DW-Link. At the time, mountain bike brands across the country were looking for a suspension design that limited pedal bob and squat and maintained a high amount of traction while braking and under power. Ibis declined to comment regarding the patent expiration.
In 2007, Chris Cocalis, who had previously founded Titus Cycles, sold his stake in that brand and started Pivot Cycles with the DW-Link as the foundation for their full-suspension bikes. Cocalis had used a Horst link design at Titus, but believed the design was limited in its application compared to the DW-Link.
“With the DW-Link, we can make the bike pedal better and get increased traction in the beginning part of the travel as well as achieving much better square edge bump performance than a Horst-Link bike,” Cocalis said in a Bike Radar interview in 2008. “We still maintain that active feel while keeping braking forces out of the equation.”
In the mid-2000s, mountain bikes were far from a new concept but suspension designers and shock engineers were still navigating a fairly fresh field, and most designs had plenty of downsides, like squatting, bobbing and becoming more rigid when a rider grabbed the brakes. Weagle and the brands that licensed the design knew they had something great on their hands.
“There’s just a lot of suspension designs that didn’t pedal well for a long time, so when you got on one that did, it was like ‘wow,’” said Chris Canfield in an interview with Singletracks. Canfield is the designer and licensor of Canfield Balance Formula, a dual link suspension platform design licensed by Revel Bikes and Canfield Bikes. When it comes to marketing a bike to customers, building a reputation on a licensed and trademarked design can be like putting a gold star on the frame.
“The customer immediately knows, ‘I know what that bike’s gonna ride like,’” said Canfield.
The role of patents
In the U.S., and for much of the world, utility patents are designed to offer inventors 20 years of legal protection from design infringement. The idea is to reward novel approaches to real world problems by giving inventors an exclusive window of time to profit off their innovations while also encouraging new technology to spread far and wide into the future.
While most countries’ patent laws are similar, inventors must apply for individual patents in each market where they hope to protect their invention. In the bike world, designers generally apply for patents in the largest markets including the U.S., Europe and Canada. Depending on the timing of applications, patents can expire in different markets at different times.
In 2013 the U.S. joined much of the rest of the world in granting patents on a “first to file” basis, rather than awarding them to the first person to come up with a new design or invention. Under this system, inventors are incentivized to patent early, and patent often, lest someone else claim rights to an important design.
The 20-year utility patent protection clock begins at the time of application, though it can take a year or more for a patent to be officially granted. During this in-between period, inventors often use the label “patent pending” to dissuade others from copying their designs.
However not every utility patent lasts 20 years. If a patent holder fails to enforce their patent they can lose their exclusive rights to its use, so holders are incentivized to take legal action against infringing products. On the flip side, while patents generally can’t be extended, inventors can work to improve upon their original design and apply for new but related patents.
Patent holders mainly profit off their inventions by becoming the exclusive provider of a particular product, or through licensing agreements. The agreements themselves may be exclusive to a single licensee, or extended to multiple parties. Inventors are free to choose who they license their technology to, and to dictate the price and terms of the license. Patents can even be assigned (sold) to another party.
Much like other inventions, DW-Link has had to fight for protection over alleged design infringement. In 2013 DW-Link Inc. sued Giant Bicycles for patent infringement and breach of contract after years of licensing negotiations and design work following the 2005 launch of Giant’s Maestro suspension design. The lawsuit was dismissed a year later. In another instance, Weagle sued Trek because their Active Brake Pivot suspension allegedly infringed upon another patented design known as Split-Pivot. Trek won the suit and Split Pivot was ordered to pay Trek’s legal costs.
Patents vs. trademarks
Like patents, trademarks are a form of intellectual property that affords various legal protections. While patents cover inventions and designs, trademarks guarantee the right to use symbols or words to represent a brand or product. Trademarks must be registered within individual countries or regions like Europe, and can generally be extended indefinitely through regular renewals.
Apart from the DW-Link utility patent, the words “DW-Link” and “DW*Link” are trademarked in the U.S. This gives the trademark holder the exclusive rights to apply those designations to anything vehicle or apparel related, including but not limited to full suspension bicycles.
Hasn’t this happened before?
DW-Link is not the first mountain bike suspension design patent to face expiration. Virtual Pivot Point (VPP) and Horst Link are two such patented designs, and what happened following the expiration of their protection could offer a preview of what’s to come of DW-Link.
Virtual Pivot Point
Today, if you hear the letters VPP, you most likely think of one brand that has used the design to incredible success.
Santa Cruz Bicycles bought the VPP patent from a small bike brand named Outland in 2001 after reaching the end of what they thought was the potential of their single pivot designs. VPP is not totally unlike DW-Link. It uses a short, dual-link design, but instead of the links rotating in the same direction like DW, the links on a VPP bike rotate in opposite directions. The heads at Santa Cruz knew the technology had potential.
“When the VPP first came out at Interbike, 1995, I thought, Holy [cow]! This thing is really cool,” Rob Roskopp of Santa Cruz told Mountain Bike Action. “It solved all the things that we were trying to address with a single pivot, and accomplished things that we couldn’t make our system do.”
Similarly to DW-Link, VPP was known for how it managed acceleration and squat. Early on, Roskopp and his partner at Santa Cruz Hans Heim exclusively licensed VPP to one other California brand, Intense. The two thought that if multiple brands were using the design, there would be “strength in numbers.”
The VPP patent expired in 2015. Diamondback took advantage of the foundation and the brand created Level Link, a design with two counter-rotating links, though it was just different enough for them to file their own patent on the improved design.
The Horst link and FSR
According to the Mountain Bike Hall of Fame, Horst Leitner built his first four-bar suspension mountain bike prototype back in 1985. By the early 1990s he had been granted a patent for his design which was licensed to Rocky Mountain Bicycles, Turner, Mongoose and Titus Bikes before the patent was sold to Specialized. In 2005 Specialized successfully blocked Scott from selling full suspension, four-bar Genius bikes in the US that were said to infringe on the patent.
By 2014 the main Horst Link patents had expired, allowing brands like Canyon to incorporate the same basic design into full suspension bikes sold worldwide. Many brands are using the Horst link design today; Norco has an elevated Horst Link system on their Shore freeride bike and the YT Virtual Four Bar system is essentially a Horst, just not in name.
Specialized, for its part, has continued to tweak the Horst Link design over the years, applying the FSR label and patenting various updates and improvements along the way. The Horst design ultimately served as a building block for many other systems, and by the time the original patent expired, the earliest licensors had moved on with further tweaks and improvements to differentiate their designs.
Suspension design patent power
While patents confer valuable protection to designs, they’ve become less important in the world of mountain bike suspension over time as shocks have improved.
“In the 90s and the early 2000s, there was a lot of [suspension layout design] being done,” said Aaron Abrams, Director of Product for Marin Bicycles. “Shock technology wasn’t very good back then, so suspension layout was much more important than it is today.”
In 2003, around the time DW-Link was patented, shocks weren’t as adjustable as they are today, and linkage designs were necessary to elicit progressivity and to counter pedal feedback.
“Fast forward to 2023 and shock technology is fantastic,” said Abrams. “Things like simple, single-pivot bikes and Horst link bikes especially were not that great until shock technology evolved to where it is now.”
Kona bike designer Doug Lafavor agrees. “I think [suspension designs] used to be more important than they are now.” Rather, he argues the biggest jumps in mountain bike suspension technology have come from suspension companies like Fox, RockShox, and Cane Creek.
No single design to rule them all
In the world of mountain bikes, there’s no such thing as a perfect design, and that’s especially true when it comes to suspension. Each design, whether it’s single pivot, Horst, VPP, or DW-Link, has its own performance characteristics and ride feel, pros and cons.
“You’re going to have some benefits that are really good in some applications, and some places where it doesn’t give you as much benefit,” said Abrams.
Everything from the amount of travel to the bike’s geometry plays into suspension design.
“There are a ton of variables involved,” he said. “You can’t just say this is the one [design] that rules them all.”
Even when brands do commit to a single basic design – say single pivot or Horst – most will tweak things in order to create a uniquely optimized ride feel. It’s all about maximizing the pros and minimizing the cons for a given design since none are perfect.
Patents aren’t the only protection
Even if one suspension design were objectively superior to the others, a design’s success or failure is heavily influenced by marketing.
“Nissan can come up with a sports car that’s ten times better than Porsche, Mercedes, or BMW but guys will buy a Porsche, Mercedes, or BMW even if it’s not as good because of the pedigree,” said Lafavor.
Brands like Pivot and Ibis have built their reputations on the DW-Link design. Any other bike brand, using Weagle’s design under another name, would be at a huge marketing disadvantage to those who can claim the DW-Link label. In this case, trademark protection will likely blunt some of the effects of the utility patent expiration.
Implementation takes time
It’s also important to recognize that a patent isn’t a blueprint. Compared to other patents in the bike industry, the DW-Link patent is heavy on theoreticals, but light on specific implementation. In that way, brands that have been refining DW-based designs for more than a decade have a leg up on newcomers hoping to capitalize on this particular suspension layout.
That being said, implementation wouldn’t be too much of a stretch for a good product design team with access to nimble manufacturing resources. “A lot of stuff can happen relatively quickly,” said Lafavor.
Pivot Cycles didn’t have much to say about the patent expiration, but did emphasize their enduring relationship with Weagle and the DW-Link and that it may take time for new brands to achieve success with the system. Chris Cocalis likened it to the expiration of the VPP patent.
“DW-Link is an equally complex design that will be difficult for most manufacturers to truly capitalize on without having the years of development that both Dave Weagle and Pivot have put in to perfect our designs,” he told us over email.
The future of DW-Link
While it seems likely some brands will incorporate various aspects of the Weagle design once the patents expire, there probably won’t be an explosion of copies.
“I agree that we’re going to see more DW [style] bikes out there, but I don’t think it’s going to be a mass exodus of design,” said Lafavor.
With the patent no longer in force, Abrams says the more likely scenario is that brands will make small moves.
“There will be some people that will kind of quietly adjust and move some things into that space to get something that they didn’t feel like they could before.”
Few, if any mid- to high-tier brands will copy the DW-Link design exactly, he says, though he leaves open the possibility that small, upstart brands may find the design attractive.
We sent Weagle a handful of questions about the patent and expiration. He didn’t want to comment directly on them, but talked about what he and his licensors and the athletes who’ve ridden the bikes to World Cup success accomplished and what they’ll pursue. Jenny Rissveds won the XCC in Lenzerheide this summer and Charlie Hatton claimed gold in Scotland on an Atherton Bikes Downhill.200, which uses the DW6, a 6-bar version of the DW-Link.
“While the early DW-Link patents were a starting point for the cycle world understanding anti-squat curves, the bikes my partners and I create have become much more advanced since then,” he said in an email. “Over the last decade, DW-Link evolved into a tech-focused company, always working on new designs and innovations that matter. Right now, we’re busy developing and refining new designs, and they seem to be working, as this year we’ve won an XC World Cup and DH World Championships!”
He added, “That there probably tells you most of what you need to know; we are still getting after it. And we plan to be for a long, long time. It’’s just what we love to do!”
