Wind tunnel development

Tech explained

The wind tunnel is a fantastic tool for the bike industry. It’s a great tool for measuring and understanding aero performance; it’s also a great marketing tool… Nothing says ‘advanced design’ like a photo of a bike in a wind tunnel. While no one would ever admit as much to us, we suspect that there are bikes that have only ever seen the inside of a tunnel for a photoshoot.

Bikes that are genuinely developed in a wind tunnel are rare because the cost of doing so is enormous. When you consider that time triallists pay £500 per hour to get into a tunnel, it’s easy to see how the bill can run to six figures. No wonder Specialized decided to build their own facility.

Felt have always been passionate believers in the value of wind tunnel development and are keen to stress the difference between that and simple wind tunnel testing of a finished product when it’s too late to change anything. Dave Koesel, Felt’s road brand manager, explains their process:

“We start by designing the tube shapes and testing them in isolation. Once the cross-sections are optimised, the tubes are joined by printing rapid prototypes and blending the joins with foam or clay. We test hundreds of tubes that yield a first version of a frame. That frame then undergoes revisions based on the outcome of tunnel testing with real parts. This is when seat-tube cut-outs and even dropout designs are abandoned and redesigned.

“We have a closet full of ‘almost ready’ plastic models and discarded ideas. We spent over two years throwing away almost ready designs because we’d come up with something faster and couldn’t ignore it.

“I’m inclined to say that, from my standpoint, the production 2014 AR is the eighth generation version but I bet that our engineers (the AR is the product of more than a dozen talented individuals here at Felt) can point to 800+ revisions and adjustments from the first concept.”