VelosplitCycling power planner FAQ
Answers about FTP, GPX files, wind, CdA and normalized power, and how far to trust the wattage targets and predicted finish times.
Is my GPX file uploaded anywhere?
No. The file is read in your browser and never sent to a server. Your last plan is kept in your browser's local storage so a reload brings it back, and nowhere else. The map tiles do load from OpenStreetMap, which can see the area you are looking at but not your file.
What is FTP and how do I find mine?
FTP, or functional threshold power, is roughly the highest average power you can hold for an hour. Most riders estimate it from a 20-minute test (about 95 percent of the average) or a ramp test, or read it from a power-meter platform such as Zwift, TrainingPeaks or Intervals.icu.
What FTP should I enter if I have not tested recently?
Use your best recent estimate and lean conservative. Every target scales with your FTP, so an optimistic number produces a plan that is too hard to finish, while a slightly low one only leaves you with energy to spare. If the feasibility warning appears, your FTP or your goal is out of step with the course.
Do I need a power meter to use this?
No, but the targets are most useful with one, or with a smart trainer. Without one you can still use the predicted finish times and the way effort varies across the course: easier on descents, steady on the flat, harder on climbs, and judge the climbs by feel.
Where do I get a GPX file for my race?
Many events publish an official GPX file on their website. Otherwise most route planners and ride-tracking apps, including Strava, RideWithGPS, Komoot and Garmin Connect, can export a course or a recorded ride as GPX.
Is normalized power the same as average power?
No. Normalized power weights harder efforts more heavily, by smoothing the power over 30 seconds and then averaging it to the fourth power, so on a hilly course it comes out higher than the plain average. Velosplit shows both, and uses normalized power to work out the intensity factor.
Why does my target wattage change on descents?
The target is a base power multiplied by a factor for the gradient. Descents steeper than 3 percent are planned as coasting, because pedalling there buys almost no time, and gentle descents get a reduced target. Climbs get a higher one.
What CdA should I use if I do not know mine?
Leave the CdA override empty. Velosplit then estimates it from your height, weight and riding position, from roughly 0.39 square metres sitting upright on the tops to roughly 0.25 on aero bars for an average-sized rider. A measured value from a field test or wind tunnel is better if you have one.
Does it account for wind?
Yes. You enter one wind speed and the direction it blows from, and for each segment the planner takes the part of that wind that is against or behind you given the direction the road is heading. It does not model gusts or a wind that changes during the ride.
How accurate are the wattage targets?
As accurate as the inputs. Martin and colleagues found that a physics model of this kind predicted measured road power to within a few watts when its inputs were measured carefully. Velosplit's inputs are estimates: your CdA comes from a regression unless you enter a measured value, and the wind is one value for the whole route. Treat the plan as a well-reasoned starting point.
Why is my predicted time different from my actual time?
The model assumes steady power on each stretch and ignores drafting, braking, cornering, changing weather and rider fatigue, and GPS elevation data can be wrong by a few metres. A gap of a few percent is normal. A large one usually points at the CdA, rolling resistance or wind you entered.
Can I plan by effort instead of a goal time?
Yes. Leave the goal time blank and Velosplit plans the route at three effort levels: low is an intensity factor of 0.65 (endurance pace you could ride all day); moderate is an intensity factor of 0.78 (tempo effort for a long, committed day); high is an intensity factor of 0.88 (race effort near threshold). It shows the estimated finish time, average power and normalized power for each.
Is it suitable for time trials, hill climbs and gran fondos?
It plans the whole route as one steady effort, which suits time trials, hill climbs, gran fondos and long solo rides. It does not model drafting, so it is not built for pack racing.