Strength of the pinatex case

I had a thought about sewing some kind of straps and buckles to the sides of the case, in order to turn it into a frame bag for my bike. I’d never heard of pinatex prior to buying my Reform, and I’m not sure how resistant it’ll be to that kind of stress. I’d probably have 2 straps that are sewed from one side to the other, which would then be hung over the top tube. Is this a good idea, or should I just buy or make a bag for it?

This idea interested me, and I looked into it briefly.

(As an aside, I am a Computer Scientist with some experience with textiles, not a physicist, and the below calculations may be overly simplistic or outright wrong. More than willing to learn if others have wisdom to share! At the very least, the references provided should allow a more knowledgeable person to be much more accurate in their recommendation!)

According to this paper, piñatex has a tensile strength nearly 1/10th (4.5 N/mm²) that of cow leather (39.5 N/mm²), and a tear resistance 1/3rd (31 N/mm) that of cow leather (82.9 N/mm). According to the crowd supply page, the rough mass of an MNT Reform is 1.9 kg. On earth, 1 kg generally exerts ~9.8 N, meaning an MNT reform generally exerts roughly 18.62 N at any one time.

Two straps means four points of contact. Assuming 1 cm wide straps (10mm), You would therefore be spreading the force out across roughly 40mm of fabric. For simplicity, we can just consider that one strap will have a square attached area, or 10mm², for a total of 40mm² of tensile spread. In these conditions it would likely be fine, since each mm² of fabric would only be dealing with ~0.4655 N of force, or roughly 1/10th of the breaking point. Tear wise, we’d be looking at a similar amount of force, but the threshold is much higher: Sitting closer to 1/20th.

However, that is a Best Case Scenario, standing still and holding the bag. Since (for instance) a 100% increase in velocity quadruples centripetal force, it’d be fairly easy to be too rough with it for the tensile strength of the fabric, which would cause damage/breaking/etc. Alongside that, I’d assume You’d want a way to carry accessories like the charging brick or similar, so that would either be more modifications (and more mass, which means more force) or a second bag anyway.

I’d probably just make or buy a whole new bag, to be honest: It’d be simpler, safer, more unique, able to carry anything You want as part of an EDC, and best of all can use the Reform inside of the unmodified piñatex case as the main pocket measurement.

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Nice, I didn’t expect a technical analysis of the materials, thanks for that! I guess what I’m getting out of this is, it’s probably possible to convert it safely with the right design and skills, but it’s not worth it. I’ll look at designing a frame bag that’ll fit the Reform, plus peripherals. Much more practical option.

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