Speedy had 16t in 05 and the America had a 17t. They changed that in 06 to 17t IMHO.
18t to 19t is a major change. At 70 you will be about 3600 RPM> Have had a 19t for years and love it. Its not a 1st gear bike but all gears are way tall, makes riding the bike a joy for me with a lot less shifting and very low RPMs cruising meaning no vibration, less exhaust noise and IMHO less wear and tear on the motor.
