The Ducati GP15 Rear Sprocket
At Mugello, Andrea Dovizioso had to retire his Ducati GP15 from an early duel with Marc Marquez due to excessive wear of the rear sprocket. Since then, Ducati has addressed the issue to make sure it doesn’t happen again. The current Ducati GP15 rear sprocket is the beefiest, most advanced one in pit lane.
Click on the image above to see the larger version and soak in the details. While most teams seem to use six-bolt systems, TEN bolts connect the gear ring to the mounting plate on the GP15. For those of us who appreciate beauty in technology, the assembly is a work of art, similar to other such items found in pit lane, but often particularly found on the Ducatis.
Previously the Ducati used a system similar to those on the other bikes. Here is the rear sprocket on the GP14.2 of Yonny Hernandez:
To further appreciate the differences between the GP15’s rear sprocket and what other teams are using, here are some more examples.
Suzuki, shown at the Monday test with a Michelin tire
While other rear sprockets on MotoGP bikes use fewer bolts that are also attached closer to the center of the assembly, the GP15’s places the bolts closer to the edge of the ring. This may be a scheme to mount the gear ring to a thicker, stronger material near the wheel hub while keeping the chain width the same. It may also be intended to make the entire sprocket assembly more rigid. It certainly looks stronger and more robust, especially compared to the Yamaha and Aprilia sprockets, which by comparison seem so simple as to be from an earlier generation of technology or perhaps even a smaller class of racing motorcycle.
For the Ducati mechanics, installing and removing the sprocket is more time intensive. I watched this fellow working on Iannone’s GP15 and there was definitely some extra spinning and torquing of bolts before he was done.
When installed on the bike, in typical Ducati style the sprocket assembly is protected by a carbon fiber cover.
It seems highly unlikely that rear sprocket problems will be an issue for Ducati in the future. I will be interested to see if any other teams adopt a similar approach with the rear sprockets their own bikes.
©2015 by Scott Jones / PhotoGP – All Rights Reserved
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