My take on honda persuing an aluminum perimeter frame is all about rigidity.To help a race mech. to tune the bikes suspension, having a stiff frame[not too stiff 97-99cr]takes it out of the equasion, making the suspesion work independantly from the frame stopping flex/twist at mount points[swing arm pivot and head stay with triple clamps].Cliff white,long time honda guy also was involved in rc racinig and most likely r&d for associated racing,he was the man back in early 1990s in rc.Back then all the off road rc trucks/buggys where going to carbon graphite frames to isolate the chassis and make the susp. work.I know its 1/10th scale racing but the principles the same,Just watch a unlimited class truck run through desert at 90 mph with 20+inches of wheel travel,with the wheels pumping up and down so fast there a blurr, while the chassis and driver float along isolated from it all.I would be suprised if cliff was not involved in the new frame.Same theory applys to a CR250 blitzing into a nasty whoop section.I only road an alum. CR once but read the that the new CRs handle excellent.I'll bet the other brands will follow out of the need to be competitive. MY TWO CENTS, PETE