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Michael Liberzon is a Toronto-based triathlon coach, bike fitter and aero tester, and host of the Endurance Innovation podcast. In this episode Michael explains what gains can be made by upgrading from a road bike to a Time Trial bike, and how things like the type of course and terrain can impact your choice of bike.
In this Episode you'll learn about:
- Expected time gains for a TT bike vs. a road bike over sprint, Olympic, half and full distance races on relatively flat courses.
- Is there a point where a course is so hilly that it makes sense to race on a road bike?
- When might it make sense to simply put extensions on a road bike rather than purchasing an entirely new bike?
- At what speed does it make sense to get out of the aerobars and sit up when climbing?
- Other considerations for racing on hilly courses like disc wheel and hydration setup
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- I host my podcast that deals with interesting and novel things about the endurance realm: Endurance Innovation Podcast with another Canadian, Andrew Buckrell.
- We talk with folks studying aerodynamics, heat transfer, coaching, and psychology.
- We talk about everything that can improve the experience of the endurance athlete.
- I am a mechanical engineer, and I am also a triathlon coach out of Toronto, Canada.
Why is a TT bike faster than a road bike in most triathlon courses?
- The answer is aerodynamics. The most significant factor impedes performance in most cycling conditions is aerodynamic drag.
- Depending on the situation and terrain, the percentage of power you put in the pedals to overcome aerodynamic drag is 70-85 %.
- There is a quote from Damon Renard: "The flip side of faster is easier."
- Being more aerodynamic will save you metabolic energy if you want to complete a racecourse faster or use less energy.
- Almost everyone will be more aerodynamic than on a road bike on a triathlon bike.
Why is the triathlon bike more aerodynamic than a road bike?
- It is not the bike itself that makes a difference.
- An entry-level triathlon bike will be more aerodynamic than an advanced road bike. The triathlon bike will have a slightly lower drag if you put the bikes in a wind tunnel.
- However, the real difference is that a triathlon bike allows the cyclist to adopt a more aerodynamic position and maintain it for an extended period.
- I will quote Sebastian Schluricke from Aerotune, the source of all numbers mentioned below. I will cite the improvements first in terms of CdA numbers.
- CdA is the drag area coefficient, and the lower this number, the better.
- The average cyclist CdA is 0.319 m2 on a road bike. If we compare this to a triathlon bike, CdA is 0.232 m2.
- These numbers might be abstract, but they correlate well with time differences.
- Using myself as an example, if I do 200 W in an Ironman, the time savings from upgrading to a triathlon bike will be around 17 minutes.
- As we go down in the distance, the time differences lower as well.
- In a half-Ironman, you will save around 8:30-9 minutes, 4-5 minutes in an Olympic distance triathlon and 2-2:30 for a sprint race.
- The power to overcome aerodynamic drag is proportional to the cube of the velocity. The faster you go, the harder it becomes to overcome aerodynamic drag.
- If you are a faster cyclist, you will go quicker if you put more power on the pedals and become more aerodynamic. However, as faster cyclists spend less time on the course, the total time savings can be smaller than a slower rider's.
- The elite triathletes now do Ironman splits in under four hours, while an age grouper can do 6+h on the same course.
- Therefore, there is more net opportunity to save time for a slower person.
- Everyone should pay attention to Aerodynamics, even if you are only trying to finish the race within the time limits. (saving 20 minutes can be the difference between doing it or not)
Fitting a road bike with TT extensions
- You see this in the ITU circuit.
- The road bikes are not less aerodynamic, as the real difference in comfort while holding an aerodynamic position.
- Triathlon bikes are comfortable while adopting a more aerodynamic position, and road bikes are comfortable in a normal upright position.
- Adding aero bars, so your contact point with the handlebars is your forearms or elbows, reduces the amount of "your body" between the saddle and the handlebar. (if you lose your whole forearm as part of your reach)
- Road bikes are longer than triathlon bikes, so you should bring your saddle forward and the pads slightly back. However, this setup is not optimal for longer races.
- You do not see elite athletes adopting this setup for Ironman distances.
Selecting the right triathlon bike
- There are a lot of marketing claims in the industry. However, if you compare two bikes with two people, the results differ.
- Concerning aerodynamics, frames converged into the optimal aerodynamic shape. There are no significant differences between a frame from one manufacturer to another.
- Picking a Trek or a Cervelo frame is similar.
- However, make sure the bike you are buying has an excellent front end. The cockpit should be easy to adjust and have a broad range.
- One crucial consideration is that the bike has to fit you, so if you are buying one, make sure it fits you.
- It is harder to make a poorly triathlon bike fit you than a road bike.
- Then, I would buy a bike with a lower end frame and get adapters to adjust the front end.
- Having the bike's front end fit you and is easily adjustable is essential for someone who wants to be the more aerodynamic.
- For example, the original Cervelo P5 is still one of the fastest bikes on the market, but to perform adjustments on that bike is impossible because of the cables and hydraulic rim brakes. If you want to make any stack changes, you have to take all cables out and reassemble them. If I am doing aerodynamic testing on someone, I have to manage my expectations.
- On the other hand, you can take the new P5, and it has higher adjustability on the front end.
- All the new Cervelo bikes and Ventum bikes have a setup like this.
- The Tririg Alpha-1 bars are easy to work with while testing.
- Nowadays, there are many more options as manufacturers pay more attention to these factors.
Integration of nutrition and hydration in a triathlon bike
- Even though "naked bikes" converged in aerodynamic terms, it makes sense to have some integration, where your ability to carry your tools and hydration is not something extra on the bike.
- You would see people taping gels on the top tube in the past.
- You can do an Ironman without having nutrition in your pockets or bottles on the bike.
- Some manufacturers are better than others, so it is good to check the additional compartments are enough for your needs. (checking if the additional tools, kit, and bottles fit into them)
- This topic is why you might want to spend more money on a specific frame. Regularly, more expensive frames have more integration.
- Putting a bottle between the handlebars is a no-brainer, especially with traditional round aero bars.
- Many manufacturers are building supports for cages between the extensions. Moreover, they can sell you their aero bottles that fit into the frame.
- You lose some capacity by carrying aero bottles. The Elite aero bottle carries only 250-300 mL compared to a 600-7000 mL round bottle.
- Therefore, there are considerations about the setup that adjust to your needs and your race nutrition.
- You will have an advantage if a manufacturer thinks of how the bottle will sit behind the saddle.
- These bottles would connect to the frame through saddle rails before, and different saddle rails have different angles. Moreover, if you are running a saddle far forward, part of the seat post may obstruct your prefered mounting of the read cage.
- If a manufacturer developed a method to place water bottles in the saddle, that frame would be advantageous.
Racing on hilly courses
- This topic depends on many variables. If you look at Lanzerotti and the athletes performing well, they are all in triathlon bikes.
- They have done their models, and they selected the triathlon bike.
- While they might commit mistakes, the triathlon bike is the most optimal.
- Lanzerotti has much more elevation than a regular course. However, what goes up has to come down, and you recover some of the time loss on downhills.
- I did a quick simulation for Lanzerotti. Changing from a triathlon bike to a road bike saves around two kilos for someone of my height and weight.
- This added weight would amount to two minutes in Lanzerotti.
- However, a triathlon bike could save 17 minutes because of the aerodynamic savings.
- There are some nuances here as I will not be in aero bars all the time because I would do most climbing and some descending in an upright position.
- However, I would say that the aerodynamic savings from a triathlon bike far outweigh the weight penalties.
- The other consideration is handling, as road bikes are better suited for descends. However, athletes who struggle on descents will struggle on any bike.
- If you are doing a technical course with technical descents, disc brakes are a significant advantage because they inspire confidence in whatever you are doing.
- A triathlon bike will not be as good as a road bike when going downhill.
- In Andorra, you may want to have a road bike with extensions. You can spend some time in the aero extensions when the course allows it, but you are not there for an extended period.
- Therefore, you are offsetting the problem of the comfort of the TT extension on a road bike.
Riding in an upright position
- Everyone will produce slightly more power when they sit up. The other reason for sitting up is when doing long races. It might be good to change your position regularly to give your body a break from the position. (not for an extended period but as a proactive stretch)
- Sitting up stresses your joints because the muscle activation changes, so the strain on the muscle changes.
- Depending on your training, the amount of power you might gain when sitting up will change. If you are a pure time trial that does all training in the TT position, the gap between sitting up and having a more aerodynamic position is more diminutive.
- You can get that gap to around 5 % if you train like that often.
- If you can produce 5 % more power while sitting up for the same heart rate, an upright gives you a tiny boost concerning power, but nothing substantial.
- Therefore, you want to stay in an aero position until you ride slow.
- You might consider sitting up around 17-18 km/h. Any lower and the additional power you can produce sitting up outweigh the aerodynamic loss of an upright position.
- You are in that position for extended periods in an Ironman position that any excuse to change is valid.
Additional considerations on equipment choices for hilly courses
- Concerning disc wheels, I am for the use of disc wheels because the benefit is tremendous in the proper conditions (wind conditions).
- In crosswind situations, a disc wheel might provide negative drag for angles of yaw of 10-15º. In these situations, you might get trust from that wheel.
- The wheel is moving you forward, so I would use a disc wheel in any situation where I can use one. (with the obvious caveat that you have to be comfortable using it)
- If you have not ridden a disc wheel in the conditions of the race, you should be careful if using the disc wheel.
- While it does not affect the steering torque because the wheel is in the back, that extra side surface area creates the sailing effect in which the wind will try to move you in the direction it is blowing.
- Concerning hydration, it will depend on your skills in grabbing things at the aid stations. You want to have the bike capacity to carry hydration for an upset because if you miss one aid station, you still have hydration until the next one.
- You do not want to ruin your race by optimising aerodynamics by neglecting hydration. However, I like to run with as little hydration as possible regardless of the course profile.
- For example, on a flat course, if you have a bottle on your down tube, it will slow you down, so you want to avoid that and see where you can add that hydration.
- Therefore, you should practice grabbing bottles and minimising your risks of dropping them.
- If the aid stations are every 20-30 km, it is an excellent time to sit up for the 30s, slow down and grab some hydration.
Takeaways from the discussion
- If you like buying more bikes and focusing on triathlons, getting a triathlon bike is good.
- There are many advantages of having the correct fitting triathlon bike when doing a non-drafting triathlon race.
- It isn't easy to find reasons not to do it.
- Using the road bike with extensions works well, but aerodynamics outweighs the weight of the whole package, so I would not worry about that aspect.
- Finally, practice what you are doing, and this is not just to get as aerodynamic as possible, but also on training grabbing bottles, your race setup and holding that position.
- If you have done aerodynamic testing and the optimal position, you should aim to maintain that position for an extended period.
- If it is super slippery but cannot hold it, it will not get you to the finish line.
Rapid fire questions
What is your favourite book, blog or resource?
What is an important habit that benefited athletically, professionally or personally?
Reflect daily on what I have control of and what I have less control over, and put my energies and focus on the things I can control, and not focusing on things I cannot control. I am still working on it, but it gave some calmness in following that strategy.
Who is someone you have looked up to or who has inspired you?
Bjorg Kafta from Aerotune. He coaches some high-level athletes, developing some cutting-edge models with Aerotune, but at the same time, he is incredibly generous with his knowledge. He is not one of those who hides knowledge because he is super willing to share what he knows, and my experience with him gave me world-class advice for my training and coaching.
LINKS AND RESOURCES:
- Endurance Innovation podcast, Instagram and Michael's website (x3training)
- Road bike v Tri Bike on the Endurance Innovation podcast
- Q&A #40 - When to choose a road bike in a non-draft race, using half or full Ironmans in the lead-up to a big goal race, and making up calories after big days of training
- Q&A #8 - Time gains with Time Trial bike vs. road bike & triathlon with Multiple Sclerosis (MS)
- Aerodynamic testing in the field with Michael Liberzon | EP#294
- Virtual Wind Tunnel with Andrew Buckrell and Michael Liberzon | EP#47