Road Test: DYMA Aero Disc

What do you do when you are on summer break from university while studying Industrial Design, and feel you need to know more about the process behind taking a concept from scratch all the way through to final market delivery? You start a business of course. This is exactly what Cal Forsyth did when he started his cycling related business right here in the heart of Melbourne.

Cal has called his company DYMA, a ‘disc cover’ business, which turns your standard bike wheel, be it a shallow or deep rim, into a disc wheel. On face value, it’s a pretty simple business, but after delving a little more into it, there is a lot of thought, time and money that goes into the constant refinement and development of the DYMA range of disc covers. Even the name has had a lot of thought put into it.

In the words of Cal, “The name DYMA comes from futurist designer Buckminster Fuller’s ideation of the term ‘Dymaxion’ – a combination of the words dynamic, maximum and tension. I was introduced to Bucky’s work through an industrial design degree and associated the invention of the Dymaxion sphere as similar in principle to the product I was developing. A curved surface that creates a strong, aerodynamic form when under tension. DYMA’s logo reflects the flat celestial map of the Dymaxion sphere and corresponds with the creative and technical nature of the brand.”


Cal’s background and path to cycling related products is an interesting one. He was an accomplished motocross rider, competing at state level from a young age, and turned to cycling as life and study became busier. It was a great way to maintain fitness and develop leg strength, but was also a lot more accessible than motocross, especially while at university. Cal is more than just motocross and cycling, though as his day job is in industrial design, this has lead him to become involved in selective laser melting (a type of rapid prototyping) in metals, including titanium, for automotive applications with the CSIRO. All this knowledge has helped fuel his desire to continuously refine and improve his products.

Our first contact with Cal came in the middle of 2016 when we were looking for a disc cover to do a few comparisons with a traditional disc. It just so happened to coincide with the development of the new DYMA CL Disc Cover.

Disc covers have been around for a while in the US, and Europe, and many people have even tried their own home made options, to varying degrees of success. However, there hasn’t been an Australian product and certainly not such a slick looking option available at such an affordable price point.

How did Cal get DYMA to this point?

As we said earlier, the original idea was to go from concept to market and discover the processes involved. This entailed testing the initial design while out with a bunch of mates who were into the fixie scene, and refining the design. By early 2012 he had a branded production sample and went to market through an eBay store, Facebook marketing, and a PayPal enabled website. The sample consisted of two plastic, flat discs with eight holes on both sides. The discs each had a split that when attached to the wheel would overlap, allowing them to sit flat against the spokes. They were held in place by plastic screws placed through the holes on each disc.

The fixed gear market was the obvious demographic to go after in the initial days, and they took to the DYMA Disc Cover like a duck to water. Then the bicycle polo scene took notice. The use of disc covers is a must in bicycle polo to protect spokes for stray polo sticks. This led to 2013 and the higher end laminated model, which was originally developed to work with Core Carbon Wheels, and be attractive to the cycling and triathlon market. Orders have since flowed from as close to home as the Mornington Peninsula Triathlon Club and as far away as the Fremantle Triathlon Club, and even Team Wingate in New York, USA. Complimenting the laminate edition are the digitally printed discs, which have proved popular for branding exercises, from triathlon club representation to event and business promotion.

Through all of this Cal has continually listened to customer feedback and worked towards the 2017 models now available. Even experimenting with carbon, and although this seemed like the logical next step, it proved problematic. He simply couldn’t get the carbon light enough, and the quality was too difficult to control. However, the plan was to eliminate the need for the ‘through screws’ as the fastening system. While they are effective, there is no doubt they create deformation of the surface, which makes it obvious that the disc is, in fact, a cover and not a high end ‘real’ disc. And let’s face it – everyone wants to look like they have a high-end disc, even if it doesn’t fit the budget.

Enter the 2017 DYMA CL (Carbon Laminate) and SLi (Custom digitally printed branding) models.

They each feature:

  • 20 concealed directional fastening clips that hook over spokes and cause no surface deformation
  • The option to tape directly onto the rim wall with pre-installed tape or temporarily over the rim wall with electrical tape
  • Each order is modified to fit the
    specific hub and rim depth of purchaser’s wheel
  • The ability to remove the discs the morning of an event if race stewards give weather notice
  • Reduced overall weight
  • Affordable price – $198rrp

This is where we come in. Having had one of the initial CL prototype covers for over six months, we have put it through the wringer. Not only have we been ‘that guy’ riding down beach road with a disc wheel on a training ride, but we have tested it on terrible country roads, in wet winter Duathlons and on seriously hot summer days when the road surface is practically melting. We have lent out the CL cover to numerous other athletes who have used it in races from the local Gatorade Series to the Ironman World 70.3 Championships on the Gold Coast, to get their feedback on performance, ease of use and on how it compares to their regular race set ups. We have probably put our test model through more work in the last 6-7 months than it would normally see in a lifetime. Not once did the covers flex or rattle against the spokes, nor did they shake loose on the rough country roads, or peel away from the rim in the heat. While our test model used the pre-installed tape (meaning the covers look bonded to the rims), it did mean we couldn’t remove them with ease. If you wanted to take the covers on and off at the drop of a hat, we would suggest you go the route of using electrical tape to secure the covers to the rim of your wheel. The seal is just as good, and won’t detract from the performance of the disc cover.


The initial impression has always been great. The CL looks the goods. It has a smooth surface with a subtle carbon sheen and looks pretty much like any ‘fairing’ style disc out there – think Hed, Flo or Vision. There is even a slight sound like a conventional disc when you ride it. Each athlete we lent the covers too commented that they felt more stable and as a result faster. We noted on a number of occasions that we were quicker on our regular test loops with the covers than without, and although only anecdotal, we are confident that the covers do make a difference. Surprisingly, there is little evidence out there comparing the covers to a real disc, but most data suggests they are aerodynamically comparable, and around one second per kilometre faster than a standard non-aero rear wheel. Perhaps this is something we can look into with some of our testing protocols?

The covers also give athletes who either can’t afford a disc or are unsure if they want to commit the funds required to buy a dedicated disc, the option to get in the game. The ride quality of the wheel with the cover on is the same as a wheel without it, and may even feel more stable. The extra weight of the covers is one slight downside compared to a one-piece disc. However, this is quite minimal and has virtually no impact on overall performance for triathlon.

While we are not suggesting that the DYMA CL is exactly the same as a traditional disc, they do follow the same philosophy as industry heavyweights Hed, Flo and Vision who all use fairings bonded to spoked wheels, and who do have the data to show they are faster than a standard deep rim wheel.

At $198 compared to between $1200-$3500 for a dedicated disc, this homegrown, Aussie product is an inexpensive way to get a little bit faster, and we can’t wait to see the Cal and the DYMA Disc Covers future progress.

Images: Courtesy of Cal Forsyth



Craig McKenzie and Patrick Legge are The Test Lab. Two guys with an obsession for trialling all things related to swimming, riding and running and telling anyone who will listen what they think. Having 20 years each in the sport, they’ve seen the good, the bad and the ugly, but always loved the innovation triathlon brings to the world stage. Craig raced as a professional triathlete, winning 4 National Duathlon titles, and has worked as an exercise physiologist, osteopath and coach, while Pat has built a career running a personal training, massage and coaching business, working with State, Australian and World Champions, including Australian Olympic and Commonwealth squads whilst competing himself.

Leave a Reply

Your email address will not be published. Required fields are marked *

Sign up for the mailing list

Enter your details below to stay up to date with whats going on.