So I'm new here, looking around for info to rebuild a sbb 350 in a 1969 Jeep Wagoneer. But I wanted to show everyone my gear ratio calculator. A while back I was planning a Jeep build and I was trying to figure out the best gear ratio given several different combinations of transmissions, axles, and tire sizes. I got tired of looking up all the information and running the calculations by hand over and over so I built a little javascript craplet to do all of that for me. I put it up on my website. I figure people here could make use of it. http://www.grimmjeeper.com/gears.html Just pick your transmission from the drop down menu. For the cars, just leave the transfer case and underdrive selections as "none", while the Jeeps can select their transfer case (and underdrive if they have one). Then enter your axle ratio and your tire size. It will show you a pretty fair approximation of your RPMs at speed as well as speed at given RPMs. And you can do side-by-side comparisons to see how a change in tire size, gear ratio, or even transmission will affect you. Naturally, getting the real world tire size accurate will affect your numbers. But a lot of people over the years have said it's fairly accurate. There are no ads on the page. No fee for using it. The only script on the page is the calculator itself. I never intended to profit from it. It's just a handy tool that I like to keep around for my "what if" ideas. If other people can benefit from it, so much the better.
