How to improve your aerodynamics on a bike

Stephen Roche is a aerodynamicist and bike fitter who regularly sees his athletes qualify for Kona. So what can we learn from his aero knowledge for our own biking performance? Matt Baird meets the Bike Tailor to find out

improve your aero cycling

Brighton’s Stephen Roche (not the Irish pro cyclist) has long carved out a name for himself in the world of aerodynamics and bike fitting. “I started working in my local bike shop when I was 16, and that’s where my love of cycling began. My first passion was mountain biking, but this quickly led to road and tri,” he tells 220. “Throughout the 1990s, I managed a number of mountain bike race teams and raced around Europe. Aerodynamics were hardly touched on then. Skinsuits were used for downhill racing, but they were soon banned (you’ll have to speak to the UCI about that one!).”


Roche is now based at Stanmer Park in Brighton and, partnered with the Silverstone Sports Engineering Hub, his The Bike Tailor setup offers a custom fitting and bespoke bicycle building service only using bike brands (including Argon 18 and Parlee) that Roche has handpicked across the globe, as well as extras such as saddle pressure mapping.

“We liken it to a VIP tailored service or having a suit made on Savile Row. The experience includes a full consultation, bike fitting in their own home or office and around the clock customer care (in any time zone). Upon completion of build by our expert mechanic, a bike is hand delivered by me personally whereby the final fit is completed, regardless of location. No request is too extreme, as we love a challenge!”

Since our initial meeting in February, Roche has become 220’s unofficial aerodynamicist, putting our Ironman tri-suits through the Silverstone wind-tunnel experience. However global or local our own tri ambitions are, Roche’s knowledge of bike fitting and aerodynamics can benefit all of us.

Here we ask him for his key advice for triathletes when sourcing a bike and its components, where the biggest aero gains are made, and just what he’d spend his bike money on first. 

Matt Baird: What have been the highlights of your career in terms of triathletes you’ve helped to a specific race goal?

Stephen Roche: My favourite thing to do during my career in terms of working with triathletes has been enabling age-group riders to qualify for Kona. It’s  their passion to qualify and to be able to help them make that happen is a huge buzz. One of my female clients, a solicitor that works in London, came to me as a referral from another client. She wanted to race an Ironman, which she did after a bike fit. We continued to refine her position as she went on to compete in another Ironman and she later on qualified for Kona, which I was thrilled about. 

MB: If you had £250 to spend on tri bike tech (entry-level power meter, tri-bars, aero road helmet) or a bike fit, where would your money go and why?

SR: A bike fit 100%. That’s where your journey starts.

MB: What are the common mistakes triathletes make with their bike setup?

SR: It all starts with the bike fit. It stands to reason that, if you’re riding in the right position, your power output will increase, making you more efficient, comfortable and, therefore, it’s more sustainable overall. It’s personalised to the rider and the results I’ve seen with my athletes is proof enough. Small refinements make all the difference.

MB: How does a triathlon bike setup differ to that of a time-trial bike?

SR: A TT setup tends to be a lot more aggressive. It can accommodate this because the focus is on one discipline not three, and doesn’t have to factor in any other constraints on the body, therefore the position will be more strenuous. In essence the body is a lot flatter; you’re positioned a lot further forward to make you more aerodynamic.

MB: Just how big are the differences between clip-on tri-bars and integrated sets in terms of aerodynamics and adjustability?

SR: Clip-on bars tend to only have certain amount of movement and only one stack height, whereas integrated bars have a lot more adjustment on stack reach and width so, therefore, they’re more aerodynamic by allowing you to find the best position.

MB: How did your Silverstone Sports Engineering Hub collaboration start?

SR: At the time of the launch of the Silverstone Sports Engineering Hub, as one top aero bike fitters in the UK I was invited to visit. I was extremely impressed with the facility so opened up talks about a collaboration quick smart! What’s so impressive about the tunnel is the feeling you have when you’re there, the state-of-the-art design and that you’re working with the best people in the business. They’re forward thinking and open to new ideas to enhance the experience.

MB: Are the aerodynamic gains of a TT helmet really worth it over an aero road helmet for long-distance triathlon?

SR: A TT helmet is definitely worth it. I’ve tested this in a number of wind tunnels and can verify the results. For an Ironman distance it’s definitely faster. Yet key is not moving your head and to focus straight ahead.

MB: I recently went to the Silverstone tunnel when Henri Schoeman was having his first-ever tunnel session. He’s an Olympic medallist and Commonwealth Games champion, and yet had never been to a wind tunnel. Is tunnel analysis more affordable than many of us believe?

SR: Yes, wind tunnel fittings and analysis used to be very expensive. At previous tunnels I’ve worked in it costed around £650 for one hour. Now working at the Silverstone tunnel, it has become a lot more affordable. Fitting sessions there start at £350 and, with the new technology we’re bringing to the tunnel, we’ll be able to reduce fitting times.

MB: What are the fundamental things you’ve learnt from your years of aero testing that every triathlete should know?

SR: To wear the correct clothing, making sure your tri-suits isn’t baggy in any place. Shoe covers and calf socks are definitely beneficial aerodynamically, as long as you aren’t racing in an extremely hot climate. Avoid taping fuel such as energy gels or bars to your bike as this’ll create disturbance and, where possible, having integrated cable routing on your bike would further reduce drag.

MB: What would you ideally pick for a triathlete in terms of specific tri-suit, helmet, bike and any other aero kit?

SR: Definitely a short-sleeved tri-suit, a TT aero helmet and integrated cable routing on bike. I’d absolutely say they’d have to have a bike fit with a view to wind tunnel testing for refinements once the initial optimum position is reached.

MB: Where can you see the big gains made in the future when it comes to tri aerodynamics?

SR: We’ll be seeing more aerodynamic, lighter bikes because of the production of different and improved carbon layups. There’ll be 3D printed custom parts for bikes, including handlebars and tri bars. Tri-suits will also become more cost effective, even as the aerodynamics improved due to the development of the materials that are utilised.