After three years of extensive testing, redesign, and further refinement, we at Zinn Cycles and Clydesdale Bicycles are proud to announce our revolutionary Zinn Duro fork. We have long awaited a carbon fork that is tough enough for the abuse that gravel cyclists, bikepackers and big and tall cyclists dish out. Our vision included a carbon fiber bike fork made to match our super-strong, bike frames in durability and fit. Having a fork that can perfectly fit any size bike from small to 4XL is a huge deal in the bike industry, for tall riders and average sized riders alike. Having the confidence that your fork will never fail is now a possibility for everyone.
Our designers have spent years tackling the hurdle of creating a carbon fork that was strong enough for heavy loads and long enough for riders over 6’10” and who had a tire-size limit of 700 X 38C.
Introducing the Zinn Duro Fork
The only way to get a carbon fork strong enough for the abuse our customers put on a fork and long enough for 7-footers was to do it ourselves. We set out to design a carbon fork for bike riders that would accept road and gravel tires that would also able to handle the loads of heavy gear and larger riders. The Zinn Duro fork is perfect for aggressive gravel roads and trails, bike packing and, of course, big and tall cyclists. Its 450 mm steerer and longer lower legs means it will fit extremely tall riders and tires up to 700 X 45C. Our extensive testing included 50% higher loads than the standard ISO fork tests so we know this one can handle heavy riders or increased bikepacking loads.
Rigorous Testing
We tested the Zinn Duro carbon fiber bike fork in Germany at the industry’s best independent test lab, along with forks of other brands for comparison, and we learned a lot from it. Since we want our forks to work for a group of riders that the bike industry generally doesn’t cater to, we insisted on testing at much heavier loads than in the standard ISO fork fatigue tests required for import into Europe. We discovered that we could not make our carbon fork for heavier-set bike riders with as slim a design as other carbon fiber bike fork specialty components. We ran the risk of not lasting the 20,000 cycles ISO specified when tested at the 50% higher loads we were using. This was especially true for the braking-load tests like the one in this video. With each iteration, our fork legs got bigger until we were consistently hitting the higher testing standards we had set for ourselves.
Going Bigger
We went large size for everything on the Duro fork, not just on the fork legs. Instead of a 1-1/4” tapered steering tube, we went with a 1.5” taper, and we made it with thicker walls than other carbon fork types. For bike forks to suit a big and tall rider, everything needs to be enlarged in turn. Instead of a 12mm-diameter through axle, we went with 15mm. And instead of accepting either a 140mm or 160mm front rotor like other flat-mount forks, our forks accept either 160mm or 180mm brake rotors. Our Duro carbon fiber bike fork offers the further option of using a four-caliper flat-mount brake coupled with a 180mm rotor, like the Hope RX4+, which provides more brake power than you can find on any other road or gravel bike. The Zinn Duro fork is the finished product for the modern big and tall rider and we can’t wait for you to try it out for yourself.
