I get a lot of people asking me how they can go faster, which isn't too surprising. One of the best things about fixies is the wonderful, wonderful speed.
But, if you've already shed all the weight you can, and gotten rid of all the parts you don't need, what's left? To that, I say this: it's all about the ratio.
Your gear ratio determines a lot about the set-up and speed of your bike. The gear ratio is the relation between the crank and the rear cog. Our bikes all come set up with a 44:16 ratio, which means the crank has 44 teeth and the rear cog has 16. To determine the ratio, just divide the crank by the rear cog. For our bikes, that would be 44/16, which equals 2.8.
Math not your thing? Check out this sweet ratio calculator.
The bigger the ratio is, the higher your top speed, and the tougher it is to accelerate. The lower the ratio, the faster your acceleration, but the lower the top speed.
The next question is, what's best for me? Personally, I like 44:16. Gives you solid acceleration with a good top speed on the back end, perfect for urban riding. However, if you've been riding for a while and want to be able to go even faster, and really generate speed on the downhills, it might be time to mix it up.
The easiest way to do that is to switch out the crank. For example, for our bikes, moving from the standard 44T crank to our 48T crank would take the ratio from 2.8 (44:16) to 3 (48:16). The increased ratio would mean a higher top speed, with a bit slower acceleration. The other way would be to switch out the rear cog, changing the overall ratio that way.
Just remember, the bigger the ratio, the bigger the top speed, and you'll be ready for anything.
And that's how you go faster using the magic of ratios!