DIY Compression Straps (voile Straps, Bikepacking Straps)

Compression straps, aka ski straps, or Vail straps (or if you like a play on words in French, Voile straps) have become popular accessories for bikepacking to attach dry bags, bottles, and other items to a bike frame, forks, handlebars, and racks. The commercial straps are thick and rugged, and maybe overengineered for certain uses. I wondered if I could make a DIY version from available materials, the original thought being to use bicycle inner tubes for the strap material. Then, when I found that the newer types of lightweight bicycle inner tubes were made from thermoplastic polyurethane (TPU, same material as some commercial straps) the straps became even better. In this Instructable, I describe two ways of making a buckle, and various materials that can be used for straps.

The buckle can be either (1) one made from a tent pole or (2) a 3D-printed one based on a model I made.

Various strap materials are described, including inner tubes and bike tire liners that are used for puncture protection.

For the basics you'll need a buckle material (two options described below) and a strap material (several options described below). To make holes in the strap, you'll want a hole punch, the type that you drive through material with a hammer, and a backing material to put behind the strap when hammering the hole, like scrap piece of wood or a cutting board that you don't mind scuffing up. The punch I used was about 4mm in diameter. You'll also need a method to fasten the strap to the buckle, for example a zip tie or an iron and release paper, for heat welding certain materials.

For the buckle made from store-bought clips, you'll need something to cut the plastic for the buckle. I used a rotary tool (like Dremel) with a cutoff wheel. A fine hand saw of some sort should work. I also made one using a soldering iron to cut the plastic by melting it. That way was smelly, slower, and less precise than cutting.

A DIY buckle from store-bought materials starts with a 10cm inner tent pole hanger clip as a basis for the buckle. These are called Hanger C clips and Inner C clips. They are cheap. Currently a pack of 50 goes for about $13. I think they're made from ABS.

To make the buckle from a tent clip, we cut the tent clip where shown in the pictures along the red lines. The tent clip has a thicker, raised profile in the middle that serves as a nice guide for setting the width of the prong. Be careful to not cut all the way through that by the base of the clip (the part with the rectangular hole). The length is maybe a little less important. I found that using the reflection from an overhead light gave a good guide of where to cut, as shown in the first picture. It ends up being about 7 mm long. The additional pictures show a finished buckle with prong, and comparisons to commercially-available straps with their buckles.

Using the file provided, you can make a 3D-printed buckle.

I originally made a design with two different buckles nearly joined at their prong ends. The attached file is a single, and can be mirrored if desired.

(Aside: my first ones turned out with chunkier prongs than I intended. This was my first time making a 3D design (I used Tinkercad, which was great) and first time printing (I used Shapeways). I think I accidentally enlarged the design at one point. I also tried a double-ring design at first, but abandoned the idea.)

Feel free to mix it up and make the buckle smaller or larger, to try different widths of strap material.

Various elastic materials can be used for straps.

The first one I made was from a regular rubber bicycle inner tube.

The second one I made was from a TPU inner tube (e.g. available as Schwalbe Aerothan, or Tubolito, or Revoloop brands).

The third type I made was from bike tire liners for flat protection. These are also thermoplastic polyurethane, and are thicker than the bike inner tubes, which also means that they're stiffer (less stretchy). They're available in different colors too. I like the Mr. Tuffy type that I tried (black in the photo), but I only tried 3 different types, which all worked.

If using an inner tube, cut off the stem, and then slit it the long way to make a long, flat sheet of the tube material. Then cut it to a width of about 3/4 inch or 10mm. The length can be whatever you desire. You can cut a very long length and attach your buckle, then cut the length to fit whatever item you want to strap on, and use the rest of the tube length for even more straps by adding more buckles. You can customize your strap length to the item you intend to hold with it, or make standard lengths to use as desired. Some general guidelines are below.

• 32" (80 cm) straps are good for attaching larger dry bags to a bike.
• 25" (64 cm) straps are good for attaching 8 liter dry bags that are short and fat.
• 15" (40 cm) straps are good for attaching Nalgene bottles and other water bottles to cages.
• 12" (30 cm) and smaller straps are good for strapping poles, pumps, and other small-diameter objects.

For reference, my 16x1.375 inner tube was about 4 feet (120 cm) long after removing stem. The TPU tube I used was a Shwalbe Aerothan 26 x 2.10-2.40 size. After removing the stem, it was about 6 feet (180 cm) long, and would have yielded 4 strips, for a total of about 24 feet (730 cm) of strap material. I experimented with making some straps double-thick, so my overall strap material length was a little less than that. Tire liner materials are roughly about 6 feet (1.8 meters) long each, so if you get two that are wide enough, they can be cut down to make about 24 feet of strap material.

I found that the TPU innertube straps are stiffer (less stretchy) than a regular butyl rubber innertube, which is good. The TPU straps can be made even stronger by heat welding two layers together. In fact, the new tubes are nicely creased and flat, which would make it very easy to make a double-thick strap by just removing the stem and heat welding the layers together along the whole length. I made some double thick straps by lining up two pieces and heat welding, but next time I might just weld up the whole tube to have about 12 feet (365 cm) of double-thick straps. After cutting off the stem, of course.

If making a 3D buckle, you can alter or scale the design to whatever strap width and prong diameter you like.

Obviously, inner tubes with cracked stems or unfixable punctures are free strap material!

For a strap from a bicycle inner tube, you can use a small zip tie to pinch and hold the strap outside the buckle (the main strap and tail end, as shown in the picture). You might also try stitching the layers together with synthetic thread. I've read elsewhere about sewing inner tube material, but I haven't tried this yet.

I tried passing the strap through the buckle and gluing it with innertube patch glue, but it didn't hold and would peel apart by hand.

If you use a TPU innertube or tire liner for your strap material, you can pass the strap through the buckle and then heat weld the tail end to the main strap using a regular household iron and some release paper (one sheet on each side of the strap). I set my iron to about 4 or 5, and held it over the area to be sealed/welded for about 8-10 seconds when using a TPU innertube. I used silicone-coated release paper. I think chef parchment paper might work the same, but I haven't tried it. Tire liner materials took longer to heat, and I found that heating the strap material first, then threading it through the buckle and heating again, worked best.

As mentioned above, you can use the same method to weld two layers of the TPU material together, for a stronger strap. Some of my pictures show double-layer straps.

Using a hole punch, make holes down the center of your strap. Since the inner tube material is a little more stretchy than the commercial straps, I spaced the holes further apart, about one inch (2.5 cm) apart, and for TPU I went with something closer to 1.5 cm.

That's really all there is to it. The pictures show a butyl inner tube version (black), a TPU inner tube version (white/clear), and two tire liner versions (green and glossy black).

When using the strap, make sure you thread the strap through the buckle the right way when attaching items, so the prong is facing out. Stretch the strap to fit one of the puched holes to go over and down onto the prong, to the base of the buckle, and be amazed how easy it is to put on and take off, just like the store-bought versions.