I need some information. How do you know if the rear spring is weak? I have a st 1100. Do not have any problems when I ride alone but when two up it seems the bike go's to for down with two on it . I have set the shock and spring as stiff as it will go. Or maybe we are just to FAT! .Is 450 to 500 pownes too much when riding two up on the 1100? is there any thing I could do besides lose weight .