[Dave-R (Roppa440)]

Here are a couple of Excel spreadsheets for you to play with.

http://challenger.mpoli.fi/web/4SPEEDchart.xls is for 4-speed users.

http://challenger.mpoli.fi/web/AUTOMATICchart.xls is for automatic users.

They will show you what rpm/mph you will get in any gear for any rear tyre size or gear ratio. They will also tell you how many teeth you need on your speedo gear wheel to keep your speedo correct.

[Dave-R (Roppa440)]

If you want to see the effect of a Gear Vendors Overdrive use this chart HERE. The gears and tire sizes already entered are my own. Just replace those with your own details.