Free Speed in Your Next Time Trial

When it's just you against the clock, to go fast you certainly need a high sustained power output. But couple that with superior aerodynamics and you'll really rocket down the course.

Once you hit about 40kph as your sustained speed, the majority of any additional power output from your engine (i.e. your heart and legs) is thrown into an exponentially increasing battle against wind resistance. Ever smaller bits actually go towards more speed and ever larger chunks fight wind resistance. If you don't get your aerodynamics on the bike dialed in precisely, you'll be fighting a losing battle from the end of your 5 second countdown to the moment you cross the finish line.

The Keys To Improved Aerodynamics

So how do you fine tune your aerodynamics? Here are some key points to consider in your setup:
  • Wear a skinsuit and booties over your shoes - no flappy, loose fitting clothes. Long sleeved skinsuits have been shown to be a little more aero than bare arms
  • Use an aero helmet - there are numerous models on the market now that are all ANSI-approved for racing. Even for a triathlete, an aero helmet alone can do wonders for your bike split time. You should be able to find one these days with decent ventilation, which should be a consideration for anything longer than an Olympic distance triathlon.
  • Use aero handlebars - clip-on at least, if not a full-on set of aero bars.
  • Adjust the aero bar width to keep your forearms close together - typically the closer the better.
  • Keep your chin down - drop your chin to fill the space between your shoulders and above your forearms.
  • Keep your knees in - pedal with your knees almost touching the top tube on each stroke.
  • Upgrade your wheels to deep dish rims and a disc rear wheel if possible - an expensive option, but worth it if you can afford it. You would only use a front disc (as in the picture above) on an indoor track.
  • Put it all together on a complete time trial specific frame - another expensive option, but worth it again as you can really dial in your positioning, and leave it all set instead of fiddling with modifying your road bike setup for time trials
Leipheimer is getting his chin just right in this picture. His forearms are great, but he'd need to be careful about how parallel they are to the ground. These days, the UCI rules want your forearms to be pretty much parallel to the ground, foregoing the "praying mantis" position that emerged a couple of years back.

Now ideally you would fiddle with modifying everything in the above list by running trials in a wind tunnel. But we don't all have easy access to a wind tunnel. If you do have access, an hour of time in there can cost close to $1000.

So what can a frugal bicyclist do instead? Here's where you can find some free speed in your next time trial.

Roll Down Tests

Your free wind tunnel will be a hill that you can roll down from a standing start to record your maximal terminal velocity near the bottom. Think soap box derby, and you get the idea.

Find a relatively isolated hill with very little wind exposure and traffic. If a car runs up or down the hill during a trial, you'll have to scrap that run. You might need to plan your test runs early in the morning, as winds tend to be calm then and traffic is usually quite light. The hill should let you roll from a dead stop at the top to a terminal velocity of 40 to 45 kph or more at the bottom. If you've got someone to help you, all the better as he can hold you at the top. If you're making slight changes to body positioning, your helper can also ensure you stay consistent from one run to the next.

You'll need some type of cyclocomputer that allows you to record laps and the maximum speed in each lap. If you can download the data, that's even better. Personally, I use a Polar HRM with cadence, speed and power. It allows me to record everything for later download and analysis on my computer.

Select one element of your setup to test. For one test sequence, I varied the height of my handlebars . On another day, I tested two different time trial helmets. It's important to keep it simple - only one variable should be changed.

At a very minimum, run 5 roll-down tests for each variable setting - more if you've got the time and the legs for repeated hill climbs to the top. For my handlebars, I ran 5 tests as it's a bit fiddly to move them up and down. For my helmet test, I ran 7 tests on each helmet, as it was really easy to simply change helmets from one run to the next.

You want to begin each roll-down from the same spot at the top of your hill. When you reach the bottom, apply your brakes at the same landmark and then hit the lap button on your cyclocomputer - that way your lap will store the maximum speed attained for that roll-down.

If you're testing something simple to change like a helmet or a particular way you're holding your body (such as how low you're dropping your chin), alternate between the 2 settings for all of your roll-down tests. Your results will be interleaved, such that all even laps will be for one setting, and odd laps for the other. This will really help to factor out any slight changes in wind from one run to the next. If the setup is a little more complicated to change, like undoing bolts to move bars up or down, then do the full set of roll-downs with one setting before changing to another.

If a car passes you either up or down during a trial, DO NOT hit the lap button and simply abandon that run as quickly as possible by hitting the brakes and returning to the top of the hill.


When you've gathered all your data, look at the maximum speed attained during each trial. I throw the numbers into a simple spreadsheet, and typically average all the runs at one setting. I'll also look at the average after I've thrown out the highest and lowest speeds for a particular setting, something statisticians call discarding the outliers.

What you're looking for is a clear winner - the highest average maximum speed attained for one test setting. I did see this with my test of handlebar setup, as I found a slightly higher position was faster than an extremely low position. With my helmets, the two of them tested so close that I determined they were identical.

This method of testing is not perfect, and of course not as precise as a wind tunnel. But in my opinion, it's better than guessing. You won't always find a runaway winner in your setup, but oftentimes you'll at least see a trend you can work with, which brings me to my last point.

Practice Makes Perfect

Once you've got a position worked out, you must train in that position. The most aero setup might not allow you maximum power output. But with practice, you'll get better. I ride at least one of my workouts each week on my time trial bike - another advantage of having a separate bike for this. If you need to modify a road bike setup all the time, you're likely to get lazy and forget about it until race day.

Photo "Jamie Staff - Kilo Time Trial" by: johnthescone


  1. Well written article Kevin. Although maybe the pros might know all these tricks, us amateurs can use all the help we can get.

    And your comment "soap box derby" brought back fond memories and pulled a visual into my brain that solidified your point.

    Rod Newbound, RN

  2. Right Rod, these aero principles might not be all that new for some, but I hope the idea of "soap box derby" testing a TT setup gets some cyclists out there doing something they hadn't thought about before.

    If you get a chance to try some testing yourself, let us know here what you find out.

    Thanks for dropping by,

  3. This blog makes me realize the energy of words and pictures.It's very beneficial for me and it's filled with information.keep smiling and take care!