patclarke

I have a 05 f150 fx4 5.4L V8 Triton and I will be installing either 37X12.5R17LT or 40x14.5r17. My primary use of the truck is a daily driver but it is being built as a prerunner. This truck will not be running some giant lift kit either. It will only have a long travel suspension that may lift it a few inches. Also this truck will never be towing any thing. Im not a mechanic by any means lol so I would like some recommendations on the proper gear size for these tires and my application.

*Note
I tried to use the search feature hear and also used google.com but could not find what I am looking for. If this has been discussed before if you could link me I may have just missed it.

NGM

What gear is in it now I am thinking it would be 3.73 or 4.10 stock. If thats the case with the tire size you are going to I would say 4.56 gear would work for you and keep it streetable.

kenbasstx

4.88 is what you need to go with. If your gonna be pre running you need those tires spinning faster than they would with the 4.56 gears. Save yourself the time and money and just go 4.88. Also I was thinking about do the raptor conversion as well. Post pictures when you have it done!!

NGM

I agree with you if it were strictly a prerunner, but being a daily as well is why I said go with the 4.56. That 5.4 has plenty of *** to spin them up :-)

kenbasstx

Yeah but once you get into tire sizes like that your just dumping power out the window you could be putting into the tires. I like having the power when I want it. If all it took was a little self control and I could get decent mileage I would do it but I'm driving a lifted off roading beast. I forgot about what gas mileage was a loooooooooooong time ago. I do agree that the 5.4L can handle it. It's kinda like being on a 12 speed bike in the lowest gear peddling up a steep hill. Gonna be a lot easier in 5 or 6 than in 12th.

NGM

LOL Yea. I am just thinking of 70mph and 3500 RPMs that would SUCK

patclarke

Thank you for the suggestions. I dont know what my current gears are. Any guess as to what my RPMs would be at with the 40s at 65mph with the 4.88? I will probubly almost never pre run the vehical as I live in IDAHO lol. But at the same time I dont want my truck to be a poser so I want it to have the ability lol plus MPG are for bikes lol.

NGM

In third gear your 1 to 1 gear assuming 40's your RPMs should be 2664 at 65 mph with 4.88s with 4.56s it would be 2429. All things being equal. I was not worried about MPG when you go that big MPGs no longer matter..lol

kenbasstx

Indeed

NGM

BTW I wanna see the Raptor front end conversion when you finish it too.. LOVE that look.