I am trying to find out what gear ratio I need if I have 27” tires and at 70mph I would like my rpms to be about 2,000 or 2100 Sent from my iPhone using The H.A.M.B. mobile app
Short tires are hard on rpm at speed. 27" at 70mph and a 2.3 gear equals 2057 rpm. https://spicerparts.com/calculators/engine-rpm-calculator That is without overdrive.
http://www.csgnetwork.com/multirpmcalc.html I use this a lot. Simple google search for rpm calculator Sent from my SM-G977U using The H.A.M.B. mobile app
Just roughly it sounds like you are going to be in the range of about 3.3 to 3.5:1 going by what my F100 with T700R4 does on 235/75/15 tires. I'm running 3.54:1 gears.
Here's one I wrote. You can use it online or download it. https://docs.google.com/spreadsheet...edit?usp=drive_web&ouid=112198810104839318872