I tried that when the cop refused to show me the radar but claimed I was doing "70 plus". I was doing 55 indicated, and I told him that, he called me a liar, wrote me up for reckless operation and speeding, then told me I should thank him for saving my life. I told "70 plus" isn't a number. He wrote 70 on the ticket.What? He wrote you up for reckless driving without knowing the speed? You should go to the court and tell the judge about it. I'm pretty sure the judge will dismiss the case.
When I told them I was going to plead not guilty since I was not going anywhere near that fast and the officer refused to show me the radar, he vehemently denied that I had ever asked, and then said he wrote me the reckless op for the way I was riding, not for my speed. I ended up getting both violations.
So good luck if you fight a ticket yourself, expect the cop to lie if he has to. Just hire a traffic lawyer for $100 and they'll go to court for you and likely get it thrown out regardless of what happened.