Ok Clydes, I recently rebuilt a GT I -drive XC bike with a SID Dual air rear shock ..... the issue is that the bike frame flexes at the pivot when loaded, and pulls on the front derailure cable (Bottom Pull)..... this effectively moves the derailure enough to shift onto the next ring ,,,, I'd blame the sag, but I weigh 200 and pumped the shock to its max at 250psi and am only measuring about an inch of sag when I test it .... Anyone else had this problem? is the shock shot? I've tried a number of tuning tricks, loose, tight, under load, etc..... but nothing has worked so far