Based on the MIT research:
Can you pass the following aero-test?
- What produces more drag- your wheels or your helmet?
- True or False- 75% of how fast you go is determined by your body positioning?
- Does water bottle placement drastically affect aerodynamics?
Here are the answers to these questions and some additional rules of thumb for all triathletes. Here's how to increase bike speed without spending big bucks.
Want to increase your bike speed and spend money wisely?
- Any speed above 12 MPH makes it worth being in an aero position on aero bars
- A non-aero helmet creates 4x the drag of a nonaero wheelset
- Roughly 2/3 of drag is created by the cyclist
- Cable routing actually affects aerodynamics materially
- A water bottle on your seat tube is much more aero than one on your down tube
- Making your race number fit flatter drastically affects aerodynamics
- Your bike accounts for about 15-25% of your overall drag
The MIT ranking of value in terms of cost/second saved for practical triathletes is:
- Detailed factors, e.g. cable routing, race #, etc.
- Helmet
- Position
- Frame
- Wheels
Note - the water bottle shape was actually considered 2nd most important but was tested using a MIT custom designed one not available to the public.
There are trade-offs though, between body positioning aerodynamics and power output efficiency. It's not effective if you are super aerodynamic but losing lots of pedal power because of your positioning. Proper bike fit will help you in this regard since it determines a comfortable and aerodynamic position on the bike.
Final Takeaways:
So, you now have more information on whether to spend $2,000 on a wheelset or $200 on a helmet. Aerodynamics is critical since a 5% improvement can mean big time savings. Every rider is different too, so there is no single right answer for everyone. Are shaved legs faster than hairy ones? And just how geeky will I look in that aero-helmet?
