what is your rpms at 55 mph with 4.10 gears and 31.5" tires. mine with 3.08 gears is at 1400 rpms at 55 mph. i have a 1998 f150 flareside 2 wheel drive auto. im thinking about putting 4.10's in but need to know what the rpms would be.

 

ringmaster,

I show mathamaticaly your rpm @ 1265 going 55 mph in OD with 31.5 inch tires and 3.08. The same senario with 4.10:1 gears I show 1684 rpm.

Regards

Jean Marc Chartier

 

I have the 4.10's with the ORP 31.5's. I turn about 1850-1900 rpm at 55. Hard to be exact since my speedo actually says 90 kph.

With my old 3.55's, I was turning about 1600 at the same speed.

I noticed a huge difference in performance from 3.55 to 4.10. I can't imagine running around on 3.08's.

Ian

 

4.10's are my next mod.