Which steel 43T rear sprocket?

[xorbe]

Want to try +1/-3 (17/43) for cruising after tinkering with GearingCommander.com site (any more probably warrants 116 link chain). The steel Driven 17T front sprocket is easy to find, but the rear is a bit more challenging. I see a JT at BikeBandit, but it doesn't explicitly say 520. And "Driven Evo-Spec for Carrozzeria Wheels" (whatever that means) at SoloMotoParts, 39-47T if the site is to be believed, wouldn't mind trying 17/41 for 5K rpms @ 72 mph -- but I think that means a custom rim. VortexRacing has a pile of aluminum sizes and colors to choose from down to 38 up to 54 so there's always that, though expensive.

update: JT Sprockets: Catalogue
"JTR245/3 43" is on Amazon but not 42,44,45. Stock 46 is there, also 47.

 

[xorbe]

I gps'd my bike and came up with just under 7% eager speedo (indeed the 17T front sprocket will be an excellent fix.) What's more alarming is that the GearingCommander data is way WAY WAY off to real world speed. Like 20 mph high at top of 6th gear @ 12500 (150 vs 130 calculated). Use Primary Drive Ratio 2.25 instead of 1.955 to get more realistic numbers out of GearingCommander. Top of 1st is gps 50 mph, and GC says 57.

Have they changed the gearing since the 2009 model?