Cog ratios
 

Hi, I'm fairly new to riding fixed so would appreciate some guidance...

I'm currently riding with a 45 tooth crank and 17 tooth cog - a ratio which is really good for me.

I've just acquired a 51 tooth crank and was wondering roughly what sized cog to use which will be similar to the ratio i;ve got at the moment.

Any advice would be appreciated.
Thanks!

http://software.bareknucklebrigade.c...it.applet.html
^Go there and start plugging stuff in. I don't know your crank arm lengths or tire/wheel size, but once you plug everything in it'll give you a list of equivalent gears.

i really use a 21.

Middle school math.
 

45/17 = 51/x

(45/17)/51 = 1/x

51/(45/17) = x

x = 19.26666

19 is a bit taller, 20 a bit more lower.

Maths be gone!
http://www.theboxset.com/images/revi...re_lotr104.jpg

thanks for the help - i'm now sorted!