Some garages can get very damp. a fair amount of moisture can come straight from the ground through the concrete slab if the proper moisture barrier is not installed. Covering up bicycles with impervious materials like plastic will also accumulate more moisture around the bike causing and hastening corrosion on steel and aluminum, so it's acutally better if you do not cover the bike. You can at least get it off the ground on to hangers on the wall or from the ceiling rafters. This will keep a bit away from the ground sourced moisture. Best storage to avoid corrosion is still indoors in "conditioned" environments where the humidity and temperature is most stable. You should think twice about storing them in unfinished/not well ventilated attic spaces though, as heat in those spaces can get too high and cause or speed up degredation to plastics and rubber parts on a bike.
Keep bikes away from unshaded or uncurtained windows as UV rays from sunlight is also not kind to rubber and plastic parts, let alone the frame's paint. As they say with other products, "Store in cool, dark place" and you should be OK.
Chombi
Last edited by Chombi; 12-07-10 at 06:58 PM.