Originally Posted by Skowinski
Am I the only one that finds Ducati going to a conventional Al twin-spar frame an amazing development? They have always been so "stubborn" to do it their own, different way...
Read Preziosi on motomatters
. Lays out the reasoning pretty nicely.
Basically, running an engine-as-frame design means 1) it costs more to modify the chassis; and crucially 2) to do so may require wasting engines, which are limited in number by recent
The reasoning doesn't appear to mandate aluminium: they could have kept tubular steel if they'd thought it would have worked. However, IIRC all Ducati's tube steel chassis have relied on the engine casings to stiffen the frame at the swingarm pivot, so if they'd stayed with a "traditional" Ducati trellis design they'd still have been stymied by the engine limit, and maybe a steel full-frame would have been too heavy, carbon too tricky.
It's worth noting too that the MotoGP rules on engine numbers were designed with the currently typical Japanese chassis layouts assumed. It was obviously a good design anyway, and then the rules reinforced its advantages.