factory error is something close to 13% on every bike out there. It's so you can't sue suzuki when you get caugh speeding saying your speedo was low from the factory. It will get more off as you go faster isnce it's a percentage. buy a speedo healer. My bike was off almost 16%.
I would imagine you were going almost exactly 48.. not 55
this is also why you hear people say "I was doing 130 on my 600!" when in reality they were probably doing closer to 110 or so.
i haev a gps mounted to my k5 and yes they are way off. more so than other bikes i haev owned (R1 and hayabusa). not sure how much onteh big end but will find out when i get a few more miles on it. i will also run a couple top end runs with the tre and without (if anyone cares)