You know honestly? I have thought of using a XOSS cycling computer (https://www.amazon.com/XOSS-Speedometer-Accessories-Waterpro...).

I have used them before on various bikes and they work just fine. Battery life is about 25 hours, it is weather resistant, and then you can sync them after you record an activity. And at less than $30, if it gets lost, it isn't the worst thing in the world.