Review on 🚴 ROCKBROS Waterproof Bike Bag - Top Tube Phone Holder Pouch for Mountain Bicycles - Front Frame Touch Screen Cell Phone Holder Compatible with iPhone X, 8 Plus 7 by Brian Potter

I'm 5'10" and have a mountain bike with 29.5" wheels. If the bag was too far back my knees would hit the sides, and if the bag was too far back the part of the handlebars that touches the frame would scrape the front when cornering. Maybe it's just my settings on the bike, but I'm not sure. The pros are that it's affordable and fits your phone, a small sunscreen and maybe a small bike lock. Store your belongings when not going on a big trip. I had to put it on my wife's bike and she had no problem with knee bumps. I haven't tested the waterproofing theory yet.