Best Bike Split built its reputation as the go-to tool for race-day pacing. You upload a course file, enter your FTP and body weight, and it spits out a power plan for every segment. Useful — but at $119 per year, it is a significant expense on top of coaching software, race entries, and equipment. The good news: everything Best Bike Split does can be replicated with free tools and a bit of knowledge about the physics behind cycling performance. This guide walks you through the approach, the free calculators that make it possible, and how an AI training plan ties the whole strategy together.
What Bike Split Planning Actually Does
At its core, bike split planning is applied physics. Given your sustainable power output, your aerodynamic drag (CdA), rolling resistance, total system weight, and a course elevation profile, you can calculate expected speed at every point on the course. Best Bike Split automates this calculation and wraps it in a slick interface. But the underlying math is well understood — and you do not need a subscription to run it. The key inputs are your Functional Threshold Power (FTP), your CdA value, and the course gradient data. Get those right and your pacing plan will be just as accurate as any paid tool.The Free Tool Stack
You need three things: a way to estimate speed from power, a way to estimate your CdA, and a course file. For power-to-speed estimation, the Power-Speed Calculator on prommer.net takes your power, weight, CdA, and gradient and returns expected speed. It is the same physics equation Best Bike Split uses, just without the annual fee. For aerodynamic drag, the CdA Estimator lets you calculate your drag coefficient from field test data — no wind tunnel required. For course data, export a GPX file from Strava, Garmin Connect, or the race organizer. Most courses are available as public routes.Building Your Pacing Plan Step by Step
Start with your FTP. If you do not have a recent test result, use the Training Zones Calculator to estimate your zones from a recent hard effort. Next, estimate your CdA using the CdA Estimator with data from a flat, windless ride. Then break the course into segments: flat sections, climbs, descents, and technical portions. For each segment, plug the gradient and your target power into the Power-Speed Calculator to get expected speed and segment time. Sum the segments and you have a race split prediction that accounts for terrain, not just average speed.Why Strategy Matters More Than the Tool
The real value of bike split planning is not the software — it is the strategic thinking behind it. Knowing that you can sustain 250W for three hours is meaningless if you burn 300W on the first climb and blow up. A pacing plan forces you to think about power allocation: where to push, where to save, and how to manage the fade that inevitably comes in the final third. Use the Training Load Calculator to ensure your training in the weeks before the race matches the demands of your pacing plan. If you have been averaging 500 TSS per week but your race plan demands 600 TSS equivalent effort, something has to change.Integrating With an AI Training Plan
This is where the pieces come together. A standalone pacing calculator tells you what power to hold on race day. An AI training plan builds the fitness to actually hold it. AiTrainingPlan generates periodized training blocks targeting your specific race demands — the duration, the intensity distribution, the taper. When you feed your race target power and course demands into the platform, the AI adjusts your training load, interval prescriptions, and recovery timing to make sure you arrive at the start line ready to execute. No more guessing whether your training matches your race goals.When Best Bike Split Still Makes Sense
Full transparency: Best Bike Split is a polished product. If you race frequently with constantly changing courses, the time saved in automated segment analysis adds up. If you compete at a high level where marginal gains from optimized pacing on every segment justify the cost, the subscription pays for itself. But for the majority of age-group athletes racing a handful of events per year, the free tool stack covers the same ground. You learn more about your own physiology in the process — and that knowledge compounds.Bike split planning is not a premium feature — it is basic physics applied to your race. The free tools exist. The knowledge is accessible. And when you combine a smart pacing strategy with an AI training plan that builds the fitness to execute it, you have a complete race preparation system that costs nothing. Generate a training plan based on your race targets and see the difference structured preparation makes.