Real-World Testing

We loved the last Stumpjumper, but we wanted to make it an even more capable descender—this meant adding stiffness to the frame. To do it, we developed our own mountain-specific stiffness test that examined the connection between a rider’s hands and feet. When each get different signals, you get confused.

Extensive field-testing was performed in order to fine-tune the front-end stiffness. Our team would go ride a working version of the frame, provide feedback, and then we’d overwrap the frame with carbon plies, test it in the lab to record the stiffness value, and then give it back to the rider. We did this exact fine-tuning process over and over until we hit the perfect balance of stiffness and handling. And the result is a bike that feels like it’s riding on rails. Point it where you want, and you’re going there. This is Rider-First Engineered™ for mountain, and it delivers the ultimate trail ride—regardless of size.

We pulled out all the stops to lighten and stiffen up the frame, and what we arrived at was a vastly more efficient structure with a new sidearm design. The sidearm design directly connects all three mounting points of the rear-end and shock to the frame, and this creates a significant increase in both stiffness and performance over bumps. More explicitly, frame flex has been minimized when the rear suspension is active. In CAD, we were able to put the new 3D shape against the last iteration of the Stumpjumper, and with Finite Element Analysis (FEA), we were able to prove that the new layout was 20% more efficient. At the end of all of this, we’ve ended up with one of the lightest trail frames on the market.

With over two decades of experience with FSR, we refined our proven design. We love it, because FSR allows us to tune every part of the suspension with the least amount of compromises. Bike suspension is a marriage between the frame kinematics and the shock, after all. And given that we have our own Suspension Team (led by the King of Suspension, Mike McAndrews), we had them working hand-in-hand with the frame engineers on the bike design from day one. Because of this union, we’re now able to rely more on the frame kinematics and less on the shock damper to perfect the Stumpjumper’s ride quality. The end result? The Stumpjumper is supple over small bumps, yet it possesses a firm mid-stroke and exceptional bottom-out support. This is the suspension that makes the Ultimate Trail Bike.

 

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