Bike Panniers Backing Plate

I was seeking an affordable solution to bikepacking panniers. My requirements were: durable, long-lasting, easily removable/adjustable, modular with dry bags that I could use for other purposes (like kayaking). This is the first attempt and while I would do some things differently, the basic idea has been successful and can be made with basic tools using recycled materials. I recently took these on a multi-surface (including single-track, rough gravel and pavement) overnight trip and they met my expectations. No adjustments were needed for the backing plates and only minor tightening to the bags themselves were needed on a few occasions. They were quiet and tight and completely waterproof. Hopefully this instructable can be of use to someone looking for a similar setup. Note: this design was inspired by other pannier setups like the Rockgeist Microwave Panniers. This design centers around the Ibera Pack Rack touring rack which has an additional horizontal bar which allows the packs to be mounted lower leaving the top of the rack available.

For the backing plates only:

1) Sheet of thin plastic for TEMPLATE - I used an old plastic bin lid.

2) Thicker sheet of plastic for BACKING PLATE - I used the lids of blue plastic drums commonly used for rain barrels (2.2mm thick)

3) Markerd

4) Ruler

5) Utility Knife

6) Drill with hole saw bit

7) Recipricating Saw

8) Optional - Dremel for finer cuts and sanding. (Can be done by hand.)

Straps:

4x Voile 15" straps with buckles

1 1/2" Nylon Webbing with buckles

For the full setup:

All of the above PLUS:

2x Dry bags - I used 20 L Sea to Summit Big River Bags. These are pretty heavy duty. I think 15-20L is a good volume. 20L is more towards a touring amount of space.

Ibera Pack Rat Rack (Disc for disc brakes)

Cut out a 10" x 12" piece of plastic or cardboard. Grid it into 1" squares. Cut bottom corners with utility knife at 3" in and up. Last image shows the only places that really need to be cut. I experimented with some other attachment points but those are all that are needed.

Copy outline and inside cuts onto your plate. Using hole saw bit and drill, cut holes outside perimeter of design. Then use recipricating saw to cut outline. A drill with a 3/8 " bit can be used to cut the sides of the strap holes. Then use a dremel or utility knife to cut the rest of the inner holes. (Again all of the drill holes seen are unnecessary. Just the (8) 1" slots towards the top and then the (7) 2" slots for the webbing are needed. See last picture. Sand and file all edges, burs and and sharp points that might rub and wear down straps and bags. Dremel is good for this but can be done by hand.

The Voile rubber straps are great for attaching these plates to the rack because they are weatherproof, don't come loose and dampen vibrations. To attach follow pictures. I tried to attach multiple angles of the finished attachment. This will likely take some trial and error to get just right. I have both 15" and 20" Voile straps which is why there is different lengths of tag ends. At least 15" straps are needed and 20" is probably the maximum.

For the webbing: 1.5" seemed to be a good width for strength and stability. I sewed these straps but they can be found pretty cheap altogether. The verticle straps should be around 60" and the horizontal 56" to start with but can be cut later to minimize excess. The webbing should be fed through the backing plates in a way that also pulls the plates tightwhile being adjustable for the bags. There are multiple ways to do this but the way shown in the photos with bags attached worked fine.

These 20L bags held a full sleeping system, clothes, and food for a multi-night trip. They seemed to fit best when filled up at least 75% full so the straps could really be cinched down. These packs are heavy duty and seem to be able to withstand the minor abrasions and rubbing of bikepacking. I like that they are completely waterproof and I can remove the from the system easily. This makes setting up and breaking down camp easier.

These last pictures show how the straps can be folded and stored. Total Cost: Sea to Summit Big River 20L ($40 each) + 4 Voile Straps ($8 each) + webbing straps ($20) + the Ibera Disc Pack Rat rack ($45) = around $180 for complete system where most of materias (bags and straps) can be used for other applications.

Thanks for checking it out! Happy adventuring!