You'll gain nothing in the 60-70mph range with taller gearing. Frankly, 70mph is asking too much from a TW. 60mph, yes, 70mph, no. Simply not enough power no matter what you do with the sprockets. With 15.47, you'll wind out 4th on hills, shift to 5th, and the bike won't run over 50mph. The 3-4 and 4-5 gaps are just too wide. You'll find some hills on the BRP will require 3rd and 35mph wide open.
I've done 700 mile days with 15/54, no problem. If you are running street tires, go 15 or 47, not both, at the most.
I've done 700 mile days with 15/54, no problem. If you are running street tires, go 15 or 47, not both, at the most.
