48x18 vs 48x19 gearing
 

One is 70.1GI the other 66.4. And then there is the number of skid patches being more in the 19. Right now I have a 17 cog on the back and just want something to help me with my spinning and being able to go brakeless soon. I sort prefer the 19 but I'm afraid it would be too spinny. What do you say????

i say try both and see which one YOU like more.

At $30 a pop it is expensive..

you could just get a 46 or 44 chainring and keep the 17 out back.

well if you have a 17 now, youre around 75". most people will tell you that you will easily notice the 4-5" change to the 18. However, if you like the 17 and plan on going back to it in the future, and just want to spin spin spin, the 19 might be a better fit. If you are used to 75", 66 is probably going to be a rather large jump.

do you have any fiends with extra cogs or bikes with these ratios? Got a geared bike you could try similar ratios on?

good luck.

Looking at sheldonbrown.com/gears, the difference in your cadence for various speeds would be:

Using 48-17 and 48-19 gearing on 700 x 23C and 170mm cranks,

8.8mph 7.9mph @40rpm
13.2mph 11.9mph @60rpm
17.7mph 15.8mph @80rpm
19.9mph 17.8mph @90rpm
22.1mph 19.8mph @100rpm
26.5mph 23.7mph @120rpm


The 19T cog will require 10rpm more to get the same speed as the 17T. My road bike has a cadence sensor and based on my riding experience, 10rpm is significant.

I just finished to built my bike with 39-16, that's 65"

The other bike is 46-16

With 65" is very easy to trackstand and skid but you simply cannot go really fast

Well I ended getting the EAI 19T and I'm so glad I did. The spinning which I was fearing would be too much, is not. Nevertheless I seem to be able to pick good speed. Enough that I thought that the guy at Trackstar made a mistake and gave me something higher. My knees definetly feel good.

nothing wrong with having several cogs. last time i went to the track i saw a guy with a envelope with what looked like 4 or 5 different cogs. not to mention, as you get stronger you'll eventually want to move back to a steeper gearing.

Sure. Right now I have a 15T, a 17T and a 19T. My favorite being the last two. Now, where can I learn a good spinning technic??? I'll search the forum...