Running 15/47 Sprockets on a 2013 F800GS - Love It
I've been looking at all of the older posts in this thread, and based on that I made my decisions. I'd like to thank everyone for posting such helpful information, so this is my modest contribution:
Last night I installed the 47-tooth rear sprocket in addition to the GREAT 15-tooth front sprocket upgrade from last week, so now Iím running 15/47.
The chain was too short after adding the 47-tooth sprocket, but I didnít feel like spending $145 on a new chain because all I needed was Ĺ" more. The only thing limiting the rear wheel from moving forward was the chain-tension screw. I fastened it all the way in, but it was too long and it was sticking out and not being able to go all the way in. Since Iíll never need the full length of the screw (my 15-tooth front is permanent because it has the best balance for road/off-road), I just cut it off and everything now fits perfectly. I even had to give it a few turns, because the chain was too loose with the screw all the way in.
Two major improvements I felt right away when I visited my "private" power-line area last night:
1- The bike can crawl on 1rst gear with no throttle added. It was very useful when I was going down a steep hill without touching the clutch or the brakes, and it is harder to stall the bike even in low RPM.
2- I know Iím only gaining about 10% of torque with this setup, but when I tried climbing up a familiar steep hill I felt as if I got 50% more torque Ė it was almost effortless!
The down-side is obviously more buzz because the RPM is now ďlivingĒ in the 5,000 range (which I like doing anyway), and long highway hauls would be tiring with an estimated 6,000 RPM at 80MPH. I never checked my MPG, so I wonít be able to compare, but Iím sure it will be affected as well. However, Iím very happy because my main concern is the low-end anyway, and this $122 modification completely transformed this bike into a mud-craving bitch!
Thanks everyone for the advice!