EJB249

I have a 2005 f150 stx with 4.6 and 3.55 gears it came stock with 255/70r17 and i upgraded to 305/70r17 and i want to upgrade my gear ratio too.. I drive on the road alot to work and back so i would like a good balance between power and gas mileage. Can anyone recommend a good gear ratio that will do this for me? Any and all help is appreciated.... Thanks

sportster07

4.10's IMO are the best balance of power and cruising on the highway.

EJB249

oh ok thats one of the ratios i ws thinking it was that or 4.27 or something in that range but 4.10s seem to be the better choice. do you think the power differance will be noticeable? thank you for answering my question

driver444

+1 on the 4.10's. The 4.6 with 3.55's is a little on the light side even with stock tires. It should be at least 3.73's. With 305's I think you'd be very happy with the 4.10's

EJB249

you know i was thinking that!! ive had the truck since brand new and have put over 140k on it and its never had the power i thought it should. and now after doing a little research ive learned that it should have come with anywhere from 3.73 to 4.10 stock.. but i think you are right 4.10s will prolly be my best bet

Alpha_rico

I don't mean to steal your tread but when installing gear do you have to do the master install kit?

EJB249

i havent redone my gears yet but i beleive so

kenn_chan

to answer alpha rico's question in all fairness it depends upon the shape of the components you have in the diff right now, and if you have the neccesary tools and expertise to remove, and re-use the parts that are within spec. example: are the rear bearings in good shape, do you have a gear puller and the experience to use it correctly, then maybe all you need is a shim kit and a pinion crush tube for adjusting it. If you do not have the tools, or the expertise in using them, then mysuggestin would be to get a master kit, new bearings, crush tubes, shims.

ken

Alpha_rico

Kenn_chan would 4.10's be enough for 35's and a 5.4? This is my daily driver and my work has me on the freeway a lot. Plus 4 wheel parts said there's a national back order on most suppliers. I went to two places here in Imperial Valley and they both said they don't have 4.56. I don't want to get the 4.10 and not be happy with them. I don't do much off roading but I would like to be able to go out with my Toyota buddies and show them what Fords can do.

sportster07

I had 4.10's, they were fine I did lots of highway driving with no problems