Ultralight Dyneema Composite Handlebar roll

PERFORMANCE TESTING UPDATE – June 7, 2020  Rode today for a few hours in moderate rain over a mix of pavement and gravel.  The Dyneema Composite Hybrid Fabric bag was lightly loaded with a Sea to Summit ultralight drybag backpack containing a down jacket, pants and socks.  While riding there was visible wetting of the exterior fabric.  After the ride the bag was opened and inspected.  Water had already migrated up five tight folds on each end of the bag and was pooling at the bag openings.  Near the centre of the bag, and not adjacent to the stem, two small holes had developed and allowed water into the bag. Careful inspection of the bag/harness/bike interfaces revealed that the clamp on the bar-mounted headlight was the source of the holes. These holes developed in less than 100 km of riding.  Bags such as the Porcelain Rocket Nugget or Salsa EXP Drybag have shown no wear at this location after more than 1,000 km each of riding with similar harness configurations.  The Salsa EXP is also long enough to clip over the handlebars as pictured below.  This mounting method is secure and stable while still being loose enough for a wide range of very comfortable hand positions around the front and ends of the loop.


As a waterproof bag these items are a complete failure.  Will likely use them for cold weather ( < -10 Deg. C) riding if the premature wear issues can be resolved.

May 2020 This simple project is a first attempt to use a Dyneema fabric to create a water resistant bag weighing under 100 grams. Materials cost were around $50. The bag was sized to fill the available space between the Jones H-Loop handlebars and the upper travel limit on the Lauf suspension front fork while sitting in a DIY attachment harness. Durability is untested, however the external fabric layer appears to be quite robust. Materials used are 29″ x 36″ DCF 2.92 oz fabric, 36″ sealing tape, two pairs of 3/4″ buckles, 4 – 6″ x 3/4″ strips cut from scraps of packraft floor material, and 4 pairs of plastic snaps, sewn with Gutermann Mara 70 thread.

Subsequently a smaller second bag (~80 grams) was constructed using the remaining 25″ of the material which resulted in a slightly slimmer bag that is large enough to hold puffy layers and sleeping systems.  As pictured below the loosely packed bag contains a hooded down jacket, down pants and socks, and a Western Mountaineering HotSac VBL.  Weighing less than 1,300 grams this setup allows for a few hours sleep or for staying warm around camp or during cooler travel conditions. With no other gear on the handlebars the front of bike is light and less fatiguing during long days of travel.IMG_20200530_111823 

Completed bag with cold weather sleeping mats and a compression drybag containing 0 deg C. down sleeping bag, hooded down jacket, down pants and socks.

Assembly steps in pictures:
1. Pre-folding end of bag prior to sewing. Repeat on other end.
2. With the inside of the bag exposed stitch a seam along the length of the bag.
3. Apply sealing tape to flat-folded seam.
4. Carefully refold end seams and with the sewing machine table removed stitch each end of the bag.
5. Bar tack the four buckle straps in preparation for bartacking to the bag end.
6. Bar tack the buckles in place. 7. Install plastic snaps.
You’re done, load some gear and go ride your bike!