I am at a total loss and brain dead. My new Nittos are 6% larger that the stock tires. My current gears are 4:10. How do I figure the 6% with the 4:10 to arrive with the correct gear ratio? I also need to correct my speedometer with the SCT-X2 and not sure how to do that. Do I go into the SCT with the computer link to do this? I know I cannot do it with the hand held like I did with the predator.. Tried that. HELP