Yes they do effect handling. At least I believe they do, but not until I hit 264kmph, at that speed I begin to get a slow oscillation at the back, which is why I believe it is the bags. Since the bags never come off, I actually don't know what the bike handles like at higher speeds. But up to 264kmph, the bike is dead straight and stable. When I first got the bike I found 175kmph was fast, but now that I am used to it, I routinely run at 200 plus on open highway and the bird excels at it. It should be noted here that GIVI states the bags should not exceed 120kmph.ignoring whether those bags actually reduce top-speed, don't you think/feel they affect handling as well? I mean, 250kmph without bags must feel better than 250kpmh with 3-bags set on...