Durability of Bike Bag Fabrics
Durability is our #1 ranked bike bag fabric property in terms of our estimate of its importance to the majority of bikepackers and cycle tourists. Put simply, if your bike bag isn’t durable, what is the point?
The overall ability for a fabric to maintain its integrity when exposed to a variety of physically imposed destructive forces can be summed up as its durability. To look more deeply at a fabric’s durability for use in bike bags, we consider all the different ways that bike bags take stress and abuse. And then we look at the various ways that this stress and abuse is categorized and tested for in order to compare a fabric’s durability.
Impacts Upon the Fabric of Bike Bags
The everyday use of bike bags imposes stress and abuse on their fabrics from a variety of angles. Bicycle touring and especially bikepacking can really crank up the intensity. The bag design, the roughness of the riding and the size of the load all add variability to how the stress and abuse manifests against the fabric.
- External Bike Rub: Whether your bag is mounted to your bicycle frame, handlebars or a rack, a bike bag’s fabric bouncing and jostling against metal surfaces will test the fabric’s abrasion resistance. Of course the bag’s mounting setup, the roughness of the terrain being ridden through and the weight and positioning of the bag’s load are all important factors in how destructive those abrasive forces are. Long distance bikepacking over rough roads trails, really ramps up the abrasive forces and can really eat away at your bicycle bag. This can also pose a problem for bicycle frames and racks which is why we offer frame saver tape.
- Internal Gear Rub: Related to external bike rub, though typically much less of an issue, this is when what you’ve packed in your bike bag is eating away at the inside of the fabric. The weight, positioning and sharp edges of the gear you’ve packed in your bag all factor into its abrasive force.
- Handling: This encompasses all the stress and abuse that happens to your bike bags when you are not riding. Packing and accessing your gear generates stress and abuse from all of the tugging at the straps and fabric, manipulating the closing fixtures, rolling roll-closures and jamming gear into the bag. Mounting bags to your bike imposes the forces of strapping the bags down and utilizing the mounting hardware. Travel, storage, parking and camping with your bike bags can lead to all sorts of unexpected stress and abuse for the fabric.
- Crashing: The ability to handle the the everyday smaller bumps and scratches is a practical way to consider this form of stress and abuse. There is of course the dramatic type of event with the most potential to rip a bike bags fabric to shreds, when your bike suddenly goes down against the ground with extreme speed and force. In those instances the abuse that your bike bags can endure may be the least of your concerns. Minor crashes and jolts includes bumping your bike bags into rocks, shrubs and branches as you meander down the trail is more of what we typically consider when we think about as part of a bike bag’s long term durability. For ultralight fabrics used in bikepacking competition, racers sometimes choose the risk of compromising on crash durability to shave grams off their load.
Fabric Strength and Resistance Testing
To compare how bike bags hold up against various stresses and abuses against their fabrics, we’re looking into various forms of fabric strength tests that are sometimes deployed by fabric manufacturers.
Fabric tests alone are not sufficient to compare a bike bags ability to resist stress and abuse. Other factors of the final product contribute to a bike bag’s durability, including its fabrications techniques, mounts, design and combination of materials. However executing bike bag durability tests across a large range of bike bags in a controlled environment does not seem to viable. As a stop gap, fabric tests can provide some insights. Long-term gear reviews will continue to be the gold standard for evaluating bike bags over the long haul (pun intended).
- Tensile Strength: The maximum amount of stress that a fabric can withstand while being stretched before it breaks.
ASTM D5034 – Grab Test: This test measures measures the maximum force and elongation a fabric can withstand when a specified width of the material is clamped and pulled until it breaks. It helps assess how well a fabric can withstand loads and stresses during use. - Tear Strength: This measures a fabric’s resistance to tearing once an initial cut or puncture has occurred.
ASTM D5587 – Trapezoid Procedure: Measures the tear resistance of fabrics by using the Trapezoid Procedure, whereby a fabric sample is cut into a specific trapezoidal shape and subjected to a force until it tears. This test helps determine the fabric’s ability to resist further tearing, particularly important for fabrics that might encounter rough handling or snagging.
ASTM D2261 – Tongue Tear Method: This test involves cutting the fabric to create two “tongues” or tabs. These tabs are then pulled in opposite directions to tear the fabric further from the initial cut. This test primarily assesses the fabric’s ability to resist tearing when subjected to force from two points. - Abrasion Resistance: This is the ability for fabrics to withstand wear and degradation from repeated rubbing and contact with rough surfaces. Bikepacking frame bags are a prime example of a bag that needs fabric with high abrasion resistance to avoid wearing thin or tearing.
ASTM D4157 – Oscillatory Cylinder Method: Often referred to as the Wyzenbeek method, this test evaluates the abrasion resistance of fabric. Fabrics are subjected to rubbing against a standard abrasive surface under specific conditions to determine the number of cycles the fabric can endure before showing noticeable wear. - Stretch and Recovery Strength: The ability of a fabric to extend under tension and then return to its original shape. The ability to stretch and then recover is helpful for some bags in conforming around the gear that the bag is transporting or at openings to fit the gear inside.
ASTM D3107: This test determines the stretch and recovery properties of fabrics. It measures how much a fabric can stretch under a specified tension and how well it returns to its original dimensions after the tension is released. - Bending, Creasing and Wrinkling Resistance: Fabrics often face bending forces when they are folded or draped. Flexibility and resilience help the fabric withstand repeated bending without breaking, losing shape or becoming wrinkled.
ASTM D4032 – Circular Bend Procedure: This test determines the stiffness of fabrics by measuring the resistance of a fabric sample to bending following a circular bend procedure. It’s useful for assessing how easily a fabric can be manipulated and its propensity to resist permanent deformation.
ASTM D1388: While not exclusively a test for bending, this test can give insights into a fabric’s bending behavior by measuring its stiffness. The stiffer the fabric, the higher the resistance to bending and creasing it may exhibit.