i I HAVE A LOT TO SAY ABOUT THIS , I'M ONE OF THOSE GUY'S THAT MEASURES 33 TIMES , THEN GOES AND SETS UP THE **** TO DO IT AND THEN MEASURES AGAIN WITH A CLEAR HEAD ! . I WORKED AT A BODY SHOP FOR YEARS DOING CHASSIS WORK , AND HAVE BUILT - WORKED ON AND RACED STOCK CARS MY ENTIRE LIFE , I MENTION THIS BECAUSE THIS IS ALL MEASUREMENTS AND GEOMETRY , ... I WOULD TAKE THE BACK FENDER OFF THE BIKE ! ... PUT THE BIKE ON THE CENTER-STAND , GET THE FRONT WHEEL OFF THE GROUND SO THE BIKE IS LEVEL , SECURE THE BARS STRAIGHT , FIND THE CENTERLINE OF THE FRAME AND THE FRONT FORKS , HANG PLUMB-BOBS FROM YOUR FOOT-PEGS AND WHEREVER-ELSE WILL AID AS REFERENCE POINTS , PUT A CHALK LINE ON THE FLOOR , AND START MEASURING MY ASS OFF ! .. AND ONE THING THATS OVER LOOKED WHEN MEASURING , THIS IS JUST AN EXAMPLE ; IF YOU ARE MEASURING AND COMPARING YOU LEFT SIDE REAR WHEEL TO THE RIGHT SIDE AND ITS A 1/2 INCH OUT TO THE LEFT , YOU ONLY NEED TO MOVE IT TO THE RIGHT 1/4 OF AN INCH , BECAUSE AS YOU MOVE IT TO THE RIGHT AND CLOSE THAT GAP A 1/4 INCH , YOU JUST ADDED A 1/4 INCH OF GAP ON THE LEFT SIDE , SO THAT A 1/2 INCH TOTAL OF CHANGE ! .. I HAVE **** UP MYSELF BY NOT REMEMBERING THIS , THATS WHY I'M REMINDING YOU , AND THAT WHY YOUR ALWAYS BETTER OFF SQUARING EVERYTHING UP AND FINDING THE TRUE CENTER-LINE BEFORE DOING ANY MEASUREMENTS , BECAUSE " CENTER IS CENTER " ! .. IT IS WELL WORTH THE EFFORT AND WILL PAY OFF IN THE LONG RUN !