The race power calculator analyzes all data in your Stryd account to estimate race time based on power. Suunto nor Polar record all the available Stryd metrics. Those watches record pace, distance, power and cadence from Stryd but do not record form power and other Stryd metrics.
Therefore, the power estimate will be accurate for each distance but the predicted race times can be incorrect.
To address this problem, Suunto and Polar users should upload the Stryd data with the Stryd app on the phone. The Stryd platform will attempt to merge the watch and Stryd data into one data set.