Jumping off the Diesel Bandwagon - UPDATED
Well, after two Cummins diesels that I thoroughly enjoyed, I am going to place a factory order for a RAM 2500 with the 6.4L Hemi, 4.10 gears, rear air suspension, Laramie and plenty of added options. ...
Forum Discussion
Just for gits and shiggles, the formula for determining rpm is
mph X trans ratio X axle ratio X 336/ tire diameter.
70mph X .82 X 3.73 X 336/32" = 2248 rpm
336 is the constant. Works for any speed, ratio and tire size. I play with this formula to determine which gear ratio gives peak torque rpm at 60-65mph for interstate hills. With "my" '05 Hemi Ram and now my 5.4L F250 with Torqshift it works out to be the 3.73. The 4.10 was a little short and the 3.55 would be a tad too tall. Different transmission ratios will change the outcome altogether.
mph X trans ratio X axle ratio X 336/ tire diameter.
70mph X .82 X 3.73 X 336/32" = 2248 rpm
336 is the constant. Works for any speed, ratio and tire size. I play with this formula to determine which gear ratio gives peak torque rpm at 60-65mph for interstate hills. With "my" '05 Hemi Ram and now my 5.4L F250 with Torqshift it works out to be the 3.73. The 4.10 was a little short and the 3.55 would be a tad too tall. Different transmission ratios will change the outcome altogether.
