I put on my 43 tooth rear sprocket today and it cured the speedo error. With the 46 tooth I use to drive 75 on the highway and had everybody passing me. Now 75 is close to actually going 75. I went through one of them speed things near a school at 45 and it said I was going 44. I can feel a loss of power in 6th gear though with the new sprocket. You also have to give it more gas in 1st to take off.