A common question from many new folks is "When do I shift?" There are a few answers that newbies get, and some are wrong, some are right. This is just another method to use. First, you'll want to get the gear ratios. Plug the gear ratios into this site: http://www.housemanautosport.com/ratio calculator.htm Then you'll need the diameter of your drive tires. Every tire is different, and wears differently, so you'll need to use your judgement. I plug it into the miata.net tire calculator: Tire size calculator Input the data you just collected, and submit it. Now you'll have some numbers, use these to work by. Go to a strip and test them out. There's some experimentation, but it's pretty on-the-money. Now, stop asking "When do I shift?".