# Is the second decimal important in the ring/cog ratio?

The ring of my single speed is starting to wear out now that I'm approaching the 10k km and I'm planning to do an upgrade.

Most of the crank sets that I find interesting only come in 48–51 teeth.

I'm currently riding a 44 teeth with 16 teeth rear cog, that makes 44/16 = 2.75. I really like the setup as it is enough to get away with most hills near my city and I still can ride quite fast.

Will I notice any difference if I go with any of the following?

• 48t and 17t = 2.82 (+0.07)
• 50t and 18t = 2.77 (+0.02)
• 49t and 18t = 2.72 (-0.03)
• This ratio translated directly to the ratio between speed and cadence (with a constant factor that depends on you rear wheel size). So, when you are riding with the cadence you are used to for 25km/h, you will be riding at 24.35km/h, 24.75km/h, or 25.26km/h, respectively. Those are differences less than 1km/h. My gears are spread in such a way that they are roughly 4km/h apart. So, for the later two, the difference is about the 16th part of a gear. You won't notice that. Sep 23, 2018 at 22:03