Definition: A bag that carries all your mountain bike gear in your vehicle to the trailhead I used to travel very light to the trailhead. But I have begun to carry more options with me as of late. For example, I have been using a 3 compartment bag for the last couple of years. It consists of: A small black nylon bag with two nylon strap handles that Velcro together over the top. A straight zipper on top lengthwise straight down the middle for one large compartment that I just carried my half face helmet in. A side pocket with a zipper on top that I could get a few small items in it like a couple pair of sunglasses, xtra pair of socks, my gloves, halo, garmin, xtra food bar. A "U" shaped zipper on one end that is a bag-like compartment made for putting your shose in. It is designed for this and shares the main compartment area for my helmet. It worked great until I got a full face now both my shoes and my full face are too much for the main compartment area. Now, I often additionally carry my full face option, armor, a couple of water bottles, a change of clothes, the option of baggies (since this is tough on @herzalot if I don't), my GoPro, leggings, arm warmers, jacket, blah blah, blah... Note: I really like having the separate compartment for my dirty shoes. I did come across this review of these two bags: http://www.sicklines.com/reviews/fly-racing-moto-vault-ogio-9900/ Just hard to imagine that there are not a plethora of options out there... Any suggestions or preferences?