It’s a question that we get asked a lot. Should you ride your road bike or a Tri bike at Tremblant?
It’s true that Duplessis poses a challenge for many athletes. It’s a gradual step climb that features a handful of sharp grades and short plateaus. It’s not nearly as daunting as many think , but it still punishes the legs of even the strongest athletes. But is it worth it to trade aerodynamics for lightweight on this course?
We ran some figures in Best Bike Split to determine who would win in a fight for the fastest split; weight or aerodynamics.
But first we need to talk a little bit about our assumptions and conclusions.
We used Best Bike Split to run our calculations. BBS is an app available to anyone (though it comes with a hefty price tag!) and is used to calculate bike splits on any uploaded course.
You can use generic assumptions about your setup and weather, or you can upload a ride you’ve done under known conditions and have the app run a calculation to determine your aerodynamics (using power data, speed, terrain, and known weather patterns).
It can also pull historic and predicted weather patterns for the exact date, location, and time of your event to get the most accurate wind speeds and directions.
So how accurate can BBS be? Check it out below!
We took a power file from a ride Coach Alan did along the Aviation Parkway in Ottawa, ON in full race setup and ran it through BBS’s aero-analyzer to get an estimate of his drag coefficient, the number that measures how aerodynamic a rider is. We then took the drag coefficient estimation from this test ride and the average power he produced during a recent race into BBS.
Based on the aerodynamic calculations, average power, the historic weather on race day, and the terrain, the app produced an estimated bike split for the 90k bike course as 2:29:32.
Alan’s actual split time was 2:29:30. That’s a 2s difference between actual vs calculated.
For our Road vs Tri experiment we had to make generic assumptions about drag vs weight so this might not be as accurate as the above analysis. That being said, all else being equal, this will give an accurate representation of the difference between road bike vs Tri bike.
We ran the numbers twice using a typical female athlete and a typical male athlete for both the 70.3 and the Full distance course. We used the typical difference in weight between a road and triathlon bike (approx 2.3kg) and we assumed a drag coefficient typical of a rider on a road bike riding with hands on the hoods, and a rider on aerobars with a modest aerodynamic position. For this we assumed a basic set of 30mm rims in both setups and a basic road helmet to keep the difference limited to the difference between road setup and Tri setup. And finally, one last important consideration: the real aerodynamic difference between Road and Tri bike is the position of the rider. Being on the aerobars vs being on the hoods on typical road bars. The frame design plays a small role but not nearly as great as the actual position. This scenario assumes you are on the aerobars on all the but steepest sections of the course (ex. Duplessis).
In this analysis the Original is the road bike setup and the Adjusted is the Aero setup. Even with the added weight, riding on the aerobars on a triathlon bike saves nearly 9 minutes over the length of the course.
Again in this analysis the Original is the road bike setup and the Adjusted is the Aero setup. Adding the additional weight but going to an Aero setup still saved close to 7 minutes.
So finally we wanted to look at how much weight, in this scenario, would need to be added before aerodynamics lost its edge. In this comparison Original is Road Bike with lighter weight and more drag. Adjusted is improved aerodynamics but enough weight added to make the split times match. We had to add 17.5kg to make aerodynamics lose its edge. So unless your Aero setup is 17.5kg heavier than your lightweight setup, you are likely not benefitting from any weight savings on the bike.
In this analysis the Original is the road bike setup and the Adjusted is the Aero setup. Aerodynamics save you nearly 20minutes over the full distance.
Again in this analysis the Original is the road bike setup and the Adjusted is the Aero setup. Adding the additional weight but going to an Aero setup still saved close to 15 minutes.
In this hypothetical we assumed modest 30mm wheels with a standard road helmet. If you were to swap those wheels for a disc wheel with a 60mm front, and an Aero helmet, you will add about another kilogram of weight to your bike. But still nowhere near the weight needed for it to lose you any time compared to riding a basic road setup.
The chart on the right shows the gains (in green) and loss (red) in time by going to a more aerodynamic but heavier setup. There is a lot more green than there is red. You pay a penalty on the steepest of climbing sections, but for the most part there is nothing else but gains.
At the end of the day, your individual setup, weight, and power will determine how much or how little you gain from aerodynamics. Ultimately though, it’s almost always a benefit to go from a standard road position to a more aerodynamic riding position on the aerobars. The lightest most aerodynamic setup you can achieve is best. If the best you can do is to put a pair of aerobars on your road bike, you are still likely gaining a small advantage over riding the hoods. Fit in the aero position can affect power output and run quality, so there are a number of factors to consider when changing to an aerodynamic setup. Comfort is also a key component. But those are matters for another article…. When in doubt, ask your coach!