Midknight rider

I have a 2011 F-150 XLT with 37's I want to go to 4.56 or 4.88 gears and want to know what RPM'S y'all are pulling at 70 mph? I want to have around 2300 RPM'S at 70 which gear should I go with? I am pulling 1650 rpms at 70 now with 3.73 gears. Thanks in advance!

CPT150

I used this as a template to help me decide. Im glad I went with 4.88. http://www.4lo.com/calc/geartable.php

BUCKSHOT

I have the 4:56's for 35's and love that combo, if I were going to 37's I would definitely be going to 4:88's. Just my opinion on how my performance is with 4:56's and 35's is all. Good luck with your choice whichever way to decide to go.

Midknight rider

I was going with the 4.88 but when I went to order them a guy said I'd be pulling 2700 RPM'S at 70. But all the gear calculations I've done show I'd be at 2250-2350 at 70 with 4.88. I don't want that high of RPM'S due to the fact my truck is a weekend truck but sometimes I do drive it far. I don't mind up to 2400-2500 at 70. I have the six speed trans. What is yours? Also what RPM'S are you getting at 70? Thanks.

Midknight rider

Do you have the 4 or 6 speed trans. What RPM'S are you getting at 70? Thanks.

CPT150

its a 4 speed and Ill get it to 70 in the morning and let you know

Midknight rider

Ok thanks bro! I'm still thinking 4.88 lol

CPT150

I know my spedo is still 2.1mph off at 70mph and when I looked at 72mph it said 2287

Midknight rider

You have the 4 speed and I have the six speed transmission but the trans ratio for over drive is almost the same so I should be pulling really close to that right? Your final gear in the trans is (0.70) and mine is (0.69). I'm gonna go with the 4.88, thanks so much for the help. But If anyone sees I am wrong about this please correct me.

CPT150

no your right on. Go with the 4.88s youll be glad you did