I have a 2014 STX w/ the 5.0 and 3.55 gears. I have the 20" rims with 275/55-20 tires. I would like to go to either a 275/65-20's or 35x12.5-20 tires.

I am very fearful of the power loss and over working the engine/tranny with 34"-35" tires and the added weight.

I would like to change my gears to a better ratio for taller/heavier tires that would get me back to stock.

Would you recommend 4.10's or 4.56's.

The 4.56s seem to be a popular gear but not sure if that is the right gear for the 6 speed in my truck. I think that may be too tall and I would loose a lot of MPG on the highway.

What are your thoughts.

Thanks

 

Don't fear the gear. I don't know if you would notice a huge difference going from a 3.55 to 4.10. The 5.0 likes to rev, give it some gear.

I have 275/65r20's on my truck (EB w/ 3.31), and while the extra height and weight is noticeable, its no dog by any means. That said, I wouldn't think twice about stepping up to a 4.10 or 4.30 with the EB.

 

What is your driving like? Do you do a lot of highway? City / Hwy Percentages? Think this is what answers your question.

I had 4.88s / 37s in my last 06 F150 and it didn't get worse gas mileage than with the 3.73s.

 

Yeah but he has the 5.0 and as the other poster pointed out, it makes its power higher in the rpms compared to the EB. I do think one would benefit from a regear more with the 5.0 and I would probably go with the 4.0 to keep it a tad better than a stock 5.0 with the 3.55. 4.56 would NOT be too much but would be closer to a 3.73 or a smidge more which many really enjoy. If it were me, Id go 4.10 unless I went with the larger tires - then the 4.56...

 

I do a mix of city and highway. Probably 40% city and 60% highway.

My last truck had the 5.4L w/ a 3" body lift and 35" BFG TA/KO's. It got 9 MPG and had no low end. I loved the truck but I bought it used and with the modifications already do. No telling how long it had the lift or tires. The engine and tranny were about done at 130K miles.

I like my new truck a lot and love the power but I would like to get into some more agressive tires and probably either the Fox coil-overs or the boss...(different topic)

So with the added weight of the E-rated tires and the taller diameter, the 4'10s would probably feel about the same as my current 3.55's?

If I could get a little more pep out of the hole, would the 4.56's feel more like the 3.75's with the 34" tires?

Thanks.

I already have a tuner as well so I can make adjustments on speedo

 

Go 4.56. Give that baby some pep in her step

 

How bad would the 4.56's be on my fuel economy?

Please don't give me the "Buy a Prius" crap, just wondering.

strokin7.3, we have identical trucks! Love Sunset Metallic

 

With the larger tires the 4.56 is the ticket. It won't kill your economy you may actually gain with the step up because your working the drive train pretty hard with 35s. You'd also have the gears to go to a larger tire if you ever choose to do so.

 

Check this site out:
http://www.grimmjeeper.com/gears.html

Not sure if it has the transmission for these trucks listed, but you can put in the trans ratios if not. Also has input for tire size, tcase, and torque converter locked or not.

Will give overall ratios in all gears and tcase ranges, crawl speed, highway speed @ given rpm, and rpm@ given highway speed. Great comparisons when changing your size and any drivetrain gearing.

 

4.10s would handle 34/35 tires just fine.

Just remember the time/cost in changing gears is not something you will want to repeat! You can always get more just to be safe and get a little more pep out of your truck.