Calfee-Ellsworth Witness Full Suspension Off Road Tandem

Industry design icons, Craig Calfee and Tony Ellsworth, collaborate to deliver the most advantageous full suspension off road tandem platform in production.

Calfee Ellsworth Witness Profile_Final
The ideal off-road tandem frame for a given team would fit the rider’s build and would be very light. It would absorb shock well, but it would handle crisply because of lateral stiffness and would deliver undiminished applied pedal power to the drive train. It would be durable and not subject to fatigue failures and would be strong enough to stand up to unexpected impacts and torsion forces. It would lend itself to attractive finishing and would resist corrosion or attack by the elements.  Our full suspension off road tandem frame design leverage the beneficial and intrinsic attributes of the carbon fiber material to realize these qualities.

Calfee Ellsworth Witness Rear End Detail_Final

Suspension linkage derived from Ellsworth’s 25 years of mountain bike manufacturing experience compliments the carbon Calfee main frame.  Ellsworth’s patented Instant Center Tracking (ICT) tuned four-bar linkage design provides true zero-energy loss to suspension function.  By aligning the instant center on the chain torque line and continually tracing the chain torque throughout the range of travel, ICT is accomplished without the need of a lockout.  This keeps the suspension fully active and always on, resulting in increased traction and control, and reduced rider fatigue.


  • All frames have 36.8cm (14 ½”) bottom bracket heights and 42.5cm chainstays
  • Wheel/tire size for this chart: 27.5” (650B) wheel size with 2.25” (57mm) tire
  • Wheel/tire size changes standover and bottom bracket heights: 700 x 38 (+1cm), 27.5” (650B) x 42mm (-1cm)
  • Review technical drawings of each frame type and size, including stack and reach metrics, here.
  • Review a geometry table and product summary here.


  • 140mm of energy-efficient ICT rear suspension (by Ellsworth, Instant Center Tracking)(27.5″ wheel size – stock geometry)
  • Compatible with electronic drivetrains
  • Internal wire and cable routing
  • 10.5 pound complete frame weight
  • Off Road Tandem, Full Suspension, retails for $8,295


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