swak6287

I have a 2012 5.0 3.31 2wd. I want to wear 35s. I tow once a year, maybe twice, a travel trailer.

My dilemma is I do not want to loose the power for moving to 35s and still drive with 3.31.

Will a tune fix that problem, or just mask it?
Thanks

il_duce

3.31 gears will be pretty bad for 35's. A tuner will somewhat improve the driveability by fixing the speedo and shift points, but it will still be a slug. If you want 35's, factor in the cost of upgrading gears.

zimmer0

iTrader: (1)

would not consider anything over a 33" with a 3.31 gear ratio. Even that is really pushing it IMO.

ns_redneck

yeah i would regear for 35's. the good thing is you are only 2wd so no front gears to change too.

mechanicboy

Yea, you'll want to regear. A tune will mainly mask it on the low end by advancing the throttle opening giving the feeling of more power when it's not.

How heavy is the travel trailer?

1994Vmax

You need gears.... then tune after. Assuming a 31.5" tall tire currently you tach just under 1600 rpm at 65 mph. To maintain roughly that with a 35" tall tire you need 3.73's in the rear. But honestly with that heavy a tire 4.10 or 4.56 would be much better. 4.10 puts you at 1800 rpm at 65 mph and 4.56 is just under 2000 rpm at 65 mph.


You would be taking a lot of stress off your truck with the deeper gearing.... and you only have one differential to worry about so that's a plus!

swak6287

Ah.. thansk for reassuring me not to do it. I saw a nice truck over the weekend with 35s.. looks just like mine.
Trialer is 6k.
I just save up and grab a tru rock crawler and trailer. Leave the F150 at stock

coley909

I have 3.31s on both trucks with 275/70/18s it's been fine with both. Thinking of jumping to a 33x12.5 though when these wear out

rbrais

I have 3.55's with my 35's and it is tolerable towing a few thousand pounds (performance tune). I would like to go to 4.10's. Your 5.0 does have a little more power than my 5.4, too.


Being a 2WD, it is half as much to regear your truck. I would do that. You also have to consider that simply adding more power (custom tune) to compensate will not take any stress off the transmission.

coley909

Forgot to mention I'm ecoboost as well