So I decided to hook up the speedo healer that's just sitting under the seat doing nothing at the moment. Used a GPS and at 100KMH I'm actually doing 89KMH. I went to a calculation page I found and made it through page one. Page 2 I get asked for information on meter values and actual values and DUH...... Anyone know exactly what they're on about here? I'm off by about 10% but of coarse it can't be that simple. Anyway if you've used it and can help me out I'd appreciate it. Thanks