Registered Forum User
Big Twin
Posts: 1,973
Join Date: Apr 2004
Location: West Sussex
Mood: Train comes and I know its destination
There have been reports of mono sub-frames breaking - in fact, the 999 that BIKE magazine used for it's "440" test broke its sub-frame.
It may be that the reports were one-offs (but there were more than a couple of them!), or the fault may have been since corrected, but I'd recommend a BIP sub-frame and any necessary conversion bits you need to convert it to mono. There's lots of these kits around.
Just my opinion, it's not the definitive answer I imagine!