The app will not allow any changes to the preloaded ratios, it won’t allow you to upgrade from within the app either, It will crash, or close upon button press.

Very simple cadence/speed graph. Useful, but doesn't have 12 speed cassette support.

Was able to enter custom rings and cassette from an older MTB as I'm shopping for a different cassette, and this app works wonderfully. Only flaw I found so far is that the Gain graphs seem off, probably because it doesn't have a setting for crank length. I'm basing my decision mostly on cadence though, so gain is just a curiosity really. Thanks for this app!

No place for user input

I have used this to compare 1x11 , 2x11 , 3x10, and 2x10 Mountain bike gearing for 29, 26 and 650b wheel sizes. It really helped me understand what the gains and losses were with different solutions. I hope they update the app so it will work with the next release of IOS. I would even pay to upgrade this app.

Needs explanations and chart display in addition to the graphs.

The graphs are great. However, they are useless if you can't add your own gear size and many common sizes are not available. The ads integrate poorly and cover the graphs.