I was thinking of purchasing one of these chain deflectors. However, they come in a bunch of different sizes.

1 1/8
31.8
34.9

https://store.nexternal.com/icycles/...des-c1870.aspx

I thought maybe the sizes are for the seat tube circumference? My Litespeed circ is 115mm, not sure which one to buy? Or do you suggest a different model?