Yes, oatmeal is an excellent choice for cyclists. Complex carbohydrates (such as oats) provide sustained fuel for working muscles during a ride and can help enhance physical performance [ 1 2
1]. Carbohydrates are broken down into glucose, which is then either used for energy upon consumption or stored for later in the liver or muscle tissue as glycogen [
2]. Consuming sufficient carbohydrate helps avoid bonking during longer rides and is particularly important during high-intensity rides.
 Sang, S., & Chu, Y. (2017). Whole grain oats, more than just a fiber: Role of unique phytochemicals. Molecular nutrition & food research, 61(7), 10.1002/mnfr.201600715. https://doi.org/10.1002/mnfr.201600715
 Holesh, J. E., Aslam, S., & Martin, A. (2020). Physiology, Carbohydrates. In StatPearls. StatPearls Publishing. Retrieved from https://pubmed.ncbi.nlm.nih.gov/29083823/