The standard sprocket combination on my bike is 16 teeth on the driver and 45 teeth on the wheel sprocket. The chain has 114 links. This makes for a 6000 RPM engine speed at 100 Km/h road speed. I like riding on highways and I thought this high engine speed made no sense. I changed my sprockets to 17/40. Now the engine revs at 5000 RPM for 100 Km/h and it feels a lot better (less vibration, less noise). The change at low speed is barely noticeable. I just want to warn you about the connecting link that you will need. The chain on my 2012 VStar is not an O-ring chain. It was not evident which of the 3 choices of links to order from Sunstar. I opted for the #SS520XTG-L link which happens to be an O-ring link (the picture is the same for their 3 choices!). I used it anyway, putting the O-rings on the outboard side only as there was not enough space for all 4 O-rings. Also the connecting plate was very hard to push onto the pins. Lastly, you will have to remove 3 links from the chain to end up with 112 links with the new connecting link.