While training for my ride up Haleakala, I quickly found that endurance hill climb success for me hinged on keeping an eye on my heart rate, ensuring it does not stay above a certain level for too long, lest I blow up early. With my iPhone shoved in my back jersey pocket, the Wahoo RFLKT bike computer enabled me to monitor all my performance stats, showing when to push myself harder and giving me a vehicle to better understand my own capabilities.