Ghost Bikes is testing a prototype next generation North Shore downhill bike at the UCI World Cup race in Meribél, France, by pro team rider Johannes Fishbach.
While this design has a good bit of development still to come, it does show some major changes to the frame and a jump to 650B wheels, which they say is what should be ridden for downhill.
The bike will get a revised frame with lower main pivot and more heavily hydroformed front triangle. Rear travel is currently 180mm, but they want to get it up to 190-193mm.
Above, the current (2014) generation North Shore’s linkage and chain path. Below, the new version:
The rear moves away from high pivot with secondary pulley above the chainring and moves the main pivot 3-4cm closer to the bottom bracket. The downtube makes a bigger section at the head tube junction and now flows as one piece all the way to the BB shell.
Gone are the chunky monocoque sections at the BB and the seat tube, replaced by a machined lower pivot and shock mount.
Their tech reps said the additional pulley was robbing power when pedaling, but it was necessary to get the chain to clear the chainstay. The pivot was higher to get the kinematics right, which necessitated the rest of the design. With the move to larger wheels, the higher pivot was putting too much stress on the drive side chainstay.
The rocker arm will likely be made out of carbon, which will save a lot of weight.
Cable routing for the rear derailleur and brake will be cleaned up, too, possibly going internal. For now, they just needed to keep it safe, away from the underside of the BB.