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So my SP1 has the 520 conversion with what I believe is 15/41 gearing. Anyone know what speedo, and odo error I am seeing?

The bike shows 20,800 miles.....but I'm wondering how wrong that is
 

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I also changed to 15/41. I used the calculator on Speedo Healer's website which said -13.3%. Entered that into my SH, and now my speedo matches my GPS within +/-1 mph.

I still have the OEM rear tire size 190/50.
DAMN, -13%????

so 130 is really 116, geez I might have to get a speedo healer
 

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DAMN, -13%????

so 130 is really 116, geez I might have to get a speedo healer
OK, you started making me second-guess my figure ... I was going from recent memory (which is still questionable for me). But this confirms it ... and as I said -13.3% results in my speedometer reading +/-1 mph of my GPS.

 

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The speedo error is non-linear. With stock gearing it is about 7-8% optimistic at freeway speeds, but riding around at an indicated 35mph on surface streets it is almost dead on accurate. As your speed grows so does the amount of error so by the time you are at an indicated 130mph the % of error can easily be 13-14%

If you have lowered the gearing with a 15/41 kit expect that 7-8% error at freeway speeds to jump to about 12-13% depending on your rear tire size.

What is really interesting though is even with the optimistic error built into the speedo for stock gearing the odometer is still accurate so they did it on purpose when they engineered the bike.
 

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I haven't checked my speedo against a radar, or even another person's accurate speedo, but I think mine is WAY off! I have stock sized rear tire (190/50) which is brand new, and 15/41 sprocket set up. I was cruising on the highway at what I perceived to be 80 to 85 mph, and my speedo was showing 108! We're talking 20%+, if my estimation was close. Sounds like I need a speedo healer for sure!
 

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I haven't checked my speedo against a radar, or even another person's accurate speedo, but I think mine is WAY off! I have stock sized rear tire (190/50) which is brand new, and 15/41 sprocket set up. I was cruising on the highway at what I perceived to be 80 to 85 mph, and my speedo was showing 108! We're talking 20%+, if my estimation was close. Sounds like I need a speedo healer for sure!
I've tried various tires sizes and sprockets with my healer. I'm taking a guess that if you checked against gps, you'd be off by about 15 percent.
 
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