Get a 4iiiii Viiiiva HR strap, Garmin ANT+ speed and cadence sensor, and use the ANT+ to BTLE bridge in the Viiiiva to get the ANT+ sensor data to your iPhone (assuming it is an iPhone 5 or newer) and use an app like Strava, Ride with GPS, Wahoo Fitness, which will use GPS in your iPhone to map your ride as well as collect speed, distance, cadence and HR data.
http://www.amazon.com/4iiii-Innovati.../dp/B00BHZQ6OG $80
Amazon.com: Garmin Speed/Cadence Sensor (GSC 10): Sports & Outdoors $41
Frequently Asked Questions - 4iiii Innovations
Using the 4iiii app available here, you can configure the ANT+ sensors to pass through Viiiiva to the iPhone. Once the ANT+ device connections are configured using the 4iiii app, you will be able to connect to those devices from your favourite app using Bluetooth Smart. Follow the instructions: How-do-I-pair-Viiiiva-to-my-ANT+-sensors