How many inches are you pushing?
We've all been there. The dude/t isn't taking the hint despite the fact that you've used "interesting", "stock" and "just like the manufacturer made it" to describe the bike in question. You suspect that the tiny chainring and huge cog yield some wimpy drivetrain, and in the days before Chainvetica you couldn't be sure. Now you can.
Chainvetica does the math your PBR addled brain cannot. Given the tooth count of your chainring and cog, it calculates gear inches an ancient formula designed to sum up just how hard it's going to be turn over the cranks on your fixed gear. The more inches you're running, the harder it is to push. Use it to pick your cog. Use it to quantify the power of your massive quads.
As an added bonus, Chainvetica also calculates your speed at a cadence of 90 rpm. Your skinny jeans will make 90 rpm exactly "as fast as you can pedal" so basically, this app also calculates your ride's top speed without all the bourgeois cables and stuff.
All this functionality presented on a bed of orange and Helvetica. Good stuff.
(Does this work with SS mountain bikes? 27c tires? 650c wheels? Kilometers per hour? First of all: yuck. Secondly, we're working on that.)