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We've obviously talked about this a lot, and I’m in a bit of a unique spot, having played the “CFO” role at a small, vertically integrated manufacturing company in the outdoor space. I don’t think I’m oversharing when I say it’s a labor of love. That’s not to say Intend isn’t profitable, but let’s be real: Kornelius could probably make a lot more money as a founder/design engineer in just about any other industry. I touched on this in the podcast I did a while back, but the IQ level in the bike industry is wild. You’ve got incredibly talented...

Carbon/epoxy twill (woven with as many fibers in 0 and 90 degree orientation) mostly behaves uniformly in all directions. Using an isotropic material with stiffness (Young's modulus) of about 60 to 70 GPa is going to be pretty representative on much easier to simulate.​ Simulating how the fabric drapes over a shape is especially important when using materials with fibers all aligned in one direction (unidirectional materials) or when analyzing potential failure points.​ In this case, the key factors affecting stiffness are the shape of the component—ie open or closed cross-section, and the thickness of the material. To test this...

In other words the swing arm looks like a triangulated structure. If you are looking for stiffness, I'd look at the main pivot or the bolt on drop outs

Hey Joe, I'm not sure the motion you're trying to fix is coming from the swingarm.

Yeah I'll try and rig up something getto that can be replicated before I add any carbon!

Exactly what I was thinking of doing. I just don't have fancy machining, and also I wouldn't do it with a wheel on, I'd just load the axle directly.

Do you have a big flat heavy surface you could mount the frame to? Wouldn't take too much to replicate what Joe did in this Starling video. https://www.youtube.com/watch?v=zto62OypjUk&ab_channel=StarlingCycles

The other interesting part I don't see discussed often is that aluminium does not have a fatigue limit. The wording of that is slightly confusing if you don't know what it means, but essentially aluminium will eventually always fail from stress cycling at any stress level after enough cycles. Steel has a limit, where as long as the stress is below it's fatigue limit, it will not fail no matter how many cycles. It takes quite a while, but generally aluminium cracks around the 500 million cycle mark, at least that's what airframe engineers assume. If your a boat person...

So how available are FEA tools to your typical bike engineer? When I worked for a product design agency my boss mentioned we were quoted €25k for a seat of legit programme (he saw the built in FEA in solidworks as Mickey Mouse), he also mentioned there was a pay as you go option but it was €1k a simulation or something nuts. I understand how people use solidworks to basically create fatigue maps but modelling a swing arm seems quite sophisticated especially if you’re trying to model in a shock that maybe hasn’t hit the market.

This was a great answer, and super helpful. You can design flex into the tube set itself between the welds to help remove stress from the welds. That makes perfect sense. When I was a wee lad, we were working on the Diamondback DH frame prototype and it kept cracking at welds. The factory kept making it stiffer and stronger and it kept cracking, and we just kept chasing welds around the front triangle as they added braces or gussets (FYI THIS IS A MASSIVE OVERSIMPLIFICATION IN THE NAME OF BREVITY AND PEOPLE MUCH SMARTER AND MORE KNOWLEDGABLE THAN ME...

Hey Ryan, is there any way to run analysis or estimations of wrapping a rear end in carbon like greg minnar did on the Norco? How much wrap is needed to make a change? How m thinking about trying this on my steel rear end to mitigate some wag and wallowing feel.