We know, there’s no such thing as a stupid question. But there are some questions you might not want to ask your local shop or riding buddies. AASQ is our weekly series where we get to the bottom of your questions – serious or otherwise. Hit the link at the bottom of the post to submit your own question.
Welcome back to the Bikerumor Ask A Stupid Question series. This week we delve into aerodynamics, taking a look at which bike components offer the best bang-for-buck drag reduction to improve the aerodynamics of a regular road racing bike. Where is your money best spent? Is it on the wheels, at the handlebar, the fork, or is it actually better spent on improving the aerodynamics of you, the rider? Joining us this week are:
- Jean-Paul Ballard, CEO and Co-Founder of Swiss Side
- Gillian Jakob, Brand Manager at Cervelo
- Scott Stroot, Retül Fit Guru at Roval Components
Finally, we also have Sam Pendred joining us from Hope Technology, designer of the Hope HB.TT, a road-worthy version of the Olympic Track Bike built for the British Cycling Team that competed in Tokyo. Though he can’t comment specifically on what gains different components offer, he is able to give an unusual insight into how aerodynamics was considered in the design of the HB.TT.
Which bike parts offer the best opportunity for improving the aerodynamics of a bike? In terms of Watts saved, where is my money best spent in terms of upgrades? I’ve a standard road bike that I’d like to use for time trial racing.
Swiss Side: Even as a wheel brand, we’d be lying if we said that wheels offer the biggest aero gains. They are super important and high up the list but not at the very top. To answer this question, we need to look at the total bike and rider system and which parts of this system contribute the most drag. In road cycling, the rider is around 75% of the total aero drag, so this is our first point of call.
The rider position makes the biggest difference and costs nothing. The difference between the ‘cafe position’ (top bars, hands in the middle, straight arms) and an aero position with arms bent with hands flat on the hoods, is around 40W at 35km/h (85W at 45km/h). So, the biggest bang for buck is your yoga class to build core strength to ride lower positions for longer.
The next biggest influencer is rider apparel. A snug fitting one-piece aero suit can bring 14W at 35km/h (30W at 45km/h). Add winter gear and these numbers double again. So, being conscious of what apparel you choose is very important.

Next up are indeed the wheels. A good set of aero wheels deliver in the order of 7W at 35km/h (15W at 45km/h) over a normal set of stock low profile aluminum wheels. And, this benefit increases significantly when there is wind about due to the “sailing effect”. A good front wheel can actually generate thrust (negative) drag if the wind is right.






- Working on developing the HB.TT further and because of the radical design, we are trying things in the wind tunnel that “usually” give riders a big gain – but the design of this bike can be counter intuitive. We have seen improvements by doing things that would normally be worse for aerodynamics (rider position, especially).
- Working heavily on parts that other brands don’t have the interest/capability to manufacture. Components can be a very interesting one, like the front caliper on the HB.TT – a brand new caliper design that sits perfectly to the fork and behind the axle of the front wheel, with not a single section of exposed hose. We are looking at doing other interesting things like this with more components in the future.
- Manufacturing capability. This is a big stumbling point for lots of designs where the design is great but you can’t find a way to make it. With everything done in house here at Hope from mould/component machining – to laminating the composite products – finishing & assembly. We have total control over the whole process and it allows us to push it further and try new complex designs (usually) with high levels of success.
