My solution is lifeproof. I buy a lifeproof anyway with every new phone. I have the iPhone 5S with the nuud case and I love it. I bought the bike mount for $10 (75% off). They run those sales around Thanksgiving/Christmas, which is when I usually find a Black Friday deal on the new phone.

Nuud and Fre is 25% off right now. It may not make sense though if you are getting a new phone in sept...

But it gives a waterproof non bulky case you can use all the time, just pop it in the bike mount in a half a second and ride on...