I changed my sprockets a while ago (-1 +1) so my speedometer was way off. I finally got tired of not knowing how fast I was going, so I ordered a Speedo Tuner. I couldn't find any reviews, but it was $30 cheaper than a Speedo Healer so I figured I'd give it a shot. I installed it earlier this week. I calibrated mine on a dyno, but it can also be done with a pace car or GPS. Mine was off by 20%. So far it has been working flawlessly. If you don't need the recall feature of the Speedo Healer, save $30 and get the Speedo Tuner. :thumbsup: Correct Motorcycle Speedometer Error with SPEEDO TUNERĀ® - Easy Speedo Recalibration Device.