Austin Tri-Cyclist Blog

Friday, September 19, 2014
Texan Software Optimizing Your Bike Split

by Jack Mott

Back in June 2013, Dallas-based software company Best Bike Split quietly launched a groundbreaking new website, one that replaces the guesswork and superstition so inherent to time trialing with real data and real math. Taking inputs about the individual rider, bike, course, and weather conditions, the tool allows a user to predict finish times, optimize pacing plans, and make intelligent equipment selections. The data nerd can enter every last thing, from CdA to rolling resistance, but for the novice or less detail-oriented athlete, the software can also make intelligent guesses on many unknown minutiae. BBS has been used with great success by various local Austin professionals and top amateurs, including pro triathlete Kelly Williamson787 Racing's Steve Guzman, and ATC Racing's Kat Hunter, and the site continues to improve, offering new features regularly.

How Does It Work?

When you set up an account, you enter various personal statistics, such as your mass. You also set up a profile for each of your bikes, including the bike's mass and your aerodynamic drag on that bike.  If you don't have an estimate for your aero drag, BBS will estimate based on your height and weight and type of position. You can then upload a course you want to model from a GPS device or mapping software in .GPX format. Most popular TT and triathlon courses are likely already uploaded, and you can simply search for them and select them. From here, the magic of mathematics takes into account all your profile data, wind, corners, hills, and so on and allows you to answer pressing questions such as...

Optimal Pacing

A sample power pacing plan
Most people know that you need to go a little harder uphill and a little easier downhill to go as fast as possible for a given effort, but exactly how much to vary your power can be tricky to determine. BBS does the math for you to give you an exact answer. You can use the resulting pacing data in a number of ways: simply review it to get a high-level idea of how to vary your pace on key climbs, download the pacing plan to select GPS devices so that you have a second-by-second power goal as you race, or use BBS to output a simplified "cheat sheet" that you can memorize or tape on your top tube.

Sample Pacing Chart
Sample Cheat Sheet

Predicting Time or Power

If you have a goal time for your bike leg, like a sub hour 40k TT or 5-hour Ironman bike split, you can use the BBS goal time model to tell you what power you will have to generate on a given course to achieve it. Conversely, if you are trying to decide on a goal power for your event, you can use the regular pacing model to see what time will result at each power level.  For example, is it worth the risk to try going 20 watts harder in  your triathlon than last year? Find out exactly how much time it will save before you decide.

Optimize Equipment Selection

Yaw Angle Distribution
Challenging bike courses with lots of hills often leave athletes wondering if they should use a road bike instead of a TT bike, or light wheels instead of aero wheels. With BBS you can set up bike profiles for various options and do the math to fairly definitively decide which option is really best.  A great example of this being put to use is the Flo Cycling weight vs aero study. True aeroweenies can dig even deeper using the yaw distribution feature. This will give you data on the time you will spend at each yaw angle on course. Since the benefit of some equipment choices such as tire and wheel width depends on the yaw angle of the wind, you can use this to shave off seconds nobody else would even think about.

Optimize Your Position

The Wind Tunnel Model is an upcoming feature that will estimate your overall aerodynamic drag by analyzing your past performances. This will allow you to compare test sessions or races with different equipment or positions to see if you have managed to reduce your aero drag or rolling resistance.

How Accurate Is This?

BBS uses well-established cycling physics to make its computations. If provided with accurate input for the rider, course, and atmospheric conditions, it will produce very accurate output. Many amateurs have reported spooky accuracy even when using estimates for some inputs, such as their aero drag.  BBS also features a few case studies on their website.


BBS has free, premium, and coaching memberships available.  Premium membership unlocks unlimited bike profiles, unlimited course plan downloads, and advanced features. Coaching memberships allow you to keep profiles on all of your clients.  BBS also offers a pro-level analysis service, providing personal attention to ensure the accuracy of course and rider input, as well as increased processing power for more accurate course modeling, if necessary. Pricing plans are detailed here.

About Best Bike Split

Best Bike Split was co-founded by Ryan Cooper and Rich Harpel in June 2013 as an offshoot of their first company together, Optimized Training Labs, which uses advanced mathematics to create training plans for triathletes and runners. Ryan is a Ph.D. mathematician who specializes in optimization mathematics, while Rich’s background is in design and web development. The two met in Dallas while training for the 2006 Ironman Coeur d’Alene. Best Bike Split’s goal is to be the standard for predictive race modeling and analysis for triathletes and time-trialists racing with power meters.

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