Friday, December 6, 2013

The Carbon Commodity Conundrum: What Causes It? (Pt 1)

Last time, we laid out what the Carbon Commodity Conundrum (CCC) is, and put forth a few contributing factors.  Today, we'll look at each in turn to better understand why people can be such amazing douchebags when it comes to crabon fibre bikes.

Very few cyclists are engineers

I don't have any data to support this, but "engineer" is not the most common profession, and composites engineer a smaller subset thereof.  I stand by my assumption that most cyclists are not engineers.  If you have data to refute this, bring it on.

Many of the physical characteristics of a carbon frame that affect its performance are not visible

With steel, you can see an imperfect weld.  They're lumpy, uneven, and full of voids.  You can see a fillet braze without a smooth radius.  You can see the difference between a nice lug and a not-nice lug.  Same for the welds on aluminum and titanium.

With carbon, not so much.  I'll stipulate that on a really shitty frame, you can see wrinkles or voids in the layup, and you may be able to see nastiness inside the seat tube.  Sometimes the frame components, like cable stops and dropouts, will look shitty.  I'm disregarding that level of frame, because I don't believe those are the frames this discussion is about.

Take any carbon frame that's manufactured overseas that is not visibly shitty, and it's much more difficult.  Much like you cannot see the butting on metal tubes, you cannot see the layups in a carbon frame, and it's not a problem to make a shitty frame that looks nice on the outside.  All you need is a smooth mold and somebody who knows which is the business end of the paint gun.

Add to this the fact that there is now such a thing as an "open mold."  An open mold is just that - a frame mold that is not licensed exclusively to any particular brand; it is open for use by any brand with the money to make an order.  Two frames made from the same open mold will look identical (or near enough for this discussion), but can have vastly different performance characteristics depending on the variables mentioned above.  Think of it this way: on a traditional, TIG welded steel frame, you can have straight gauge, heavy tubing with an outer diameter of 1.125", or you can have butted, thin walled tubing with an outer diameter of 1.125".  Assuming the welding appears of the same quality on both frames, you will have two frames that look the same but perform very differently.

It is impossible to quantify the overall performance of any bicycle/frame

"But what about when they say the new 2014 Kraptastic is 30% stiffer than the 2013 Kraptastic?!"  Here's the thing: you can quantify certain aspects of stiffness.  For instance, you can clamp a bicycle frame in a rigid jig and then thread into the bottom bracket shell a lever 1 foot long.  You can then hang a known weight off that lever (or at other strategic points), and you can then measure how much the frame bends or deflects.  Clamp another frame in the same jig and hang the same weights off it and measure again.  Compare the two.  If Frame A was deflected 1.0 mm and Frame B was deflected 0.7 mm, you can say Frame B is 30% stiffer [1.0 - 0.7 / 1.0 = .30(100%) = 30%].

But so the fuck what.

Nobody tells you how the frame deflected, so you have no way of knowing in what way it's "stiffer."  The industry trend has been "vertically compliant and laterally stiff."  We're lead to believe this means the frame is stiffer in all the ways that affect pedaling efficiency, so the energy you're putting into the pedal is transferred to forward motion rather than into deflection of the frame, all the while remaining vertically compliant so your scranus doesn't take such a beating.  I stand by my original interpretation: so the fuck what.  This is a single, fuzzy variable amongst dozens of other variables that will affect performance and comfort.  Slap on a different pair of wheels and you have a bike that will feel and perform completely differently.

Matt Phillips (test director for Bicycling Magazine) wrote a great piece directly related to this on his blog:  Product reviews, which are inherently subjective, exist because it is not possible to quantify the performance of a bike, which is what would be required if you wanted to objectively evaluate them.

So far, none of the above, collectively or individually, are the cause of the CCC.  The missing, secret ingredients are the newly found, pseudotransparency of the bike industry offered by the interwebs, and the mistrust in marketing it has created.  Next time...

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