I have updated my interactive “Tire Size vs Rpm” spreadsheet to include 12.3 and 17.3 gearboxes.
Example: On 2016 and up, 12.3 with standard 21 inch tires gives about 34MPH at motor cut off of about 6800/6900 RPM With 24 inch tires about 38/39 mph.
If you would like one of these spreadsheets in Excel email me rodneyadiehl@aol.com Ask for “Tires vs Gearbox Ver. 2”
This also gets you really close:
https://spicerparts.com/calculators/transmission-ratio-rpm-calculator
Better than mine, thanks.
Rodney
Sir, I have 2006 E4 and would like to replace my wheels and tires, what size wheels and tires wold be best overall and do I need spacers or offset rims? Not real familiar with what is best for the Gem. Would 205/30/14 be any good. I appreciate your input.
Thanks
Patrick