I’ve had this project in mind since getting the Toba Roger Randonnneur rear rack for my Trek PDX. N took ownership of a Nashbar trunk bag that I picked up at a thrift store and I thought I would give this idea a try. It has enough room for tools, first aid kit, or snacks. It does have padlock eyes, so it is lockable, but that is more of a casual anti-pilfer approach than real security– it is a plastic box after all. It does have a waterproof gasket to seal the lid.
It’s not expensive as bike carry options go. I got a black MTM AC30C-40 30-caliber ammunition can and a Planet Bike tail light bracket. The mounting hardware all came from a marine supply store and I have about $24 total in the project.
I used 3/8″ black nylon pad eyes to mount the box to the rack with 10-32 stainless screws, washers and aircraft nuts. My original plan was to use a pad eye at each corner, but after looking at the box on the rack, I thought that two pad eyes on the center cross bar would be enough. That allows some sideways adjustment to get it well centered. With some careful measuring and drilling, it sits straight and even on the rack. I do need to get longer screws to have them fully seated in the aircraft nuts.
The box weighs 22 ounces and measures 7.4”(L) x 13.5”(W) x 5.1”(H) outside and 6.0”(L) x 11.2”(W) x 3.7”(H) inside under the handle slot. There are taller ammo cans available, but I wanted it low to make it easier to get my leg over the back and keep it clear of the back of the saddle. I think it looks better too. It’s about like a lunchbox
I used the Planet Bike tail light mount with a Cateye TL-LD550 lamp, which is mostly a reflector with LED’s down each side and will run in steady or flashing modes. I clipped the Planet Bike release tab off as it hung down under to no purpose. The Cateye lamp slides into the mount from the top and when the lid is closed, the light can’t come out of the mount. I sealed the mount with silicone to keep it waterproof.
The box holds my tool kit, spare tube, spare batteries, first aid kit, headlamp/flashlight and bungee cords with room to spare. It can be removed in a few minutes with a Phillips screwdriver.
My OnGuard Pit Bull Mini LS U-lock will fit with a 4′ cable, leaving enough room for my tool kit. That’s not bad for urban trips and low fuss— what the Brits call phaff. One thing about biking is the helmet/gloves/sunglasses/lock fussing whenever you get on or off the bike. With this I can drop it in and go.