500grhollowpoint

So I have an 09 FX-4 with the 5.4 and the 3.73's. I have the levelling kit, and stock tires are nearly done. Wanting to go to a 34 or so inch tire, 305/65/18 or so. I tow a 26 foot travel trailer that I use every weekend, and I live in BC. So very hilly to get where I need to go. What kind of a power and economy hit can I expect to take? Was the power loss really noticeable?

500grhollowpoint

No one has put on bigger tires and towed a travel trailer and can tell me what to expect?

zimmer0

iTrader: (1)

expect 2-3mpg loss unloaded, even more loaded. Transmission may hunt for gears until retuned. Keep an eye on transmission temps while towing IMO. Upgraded cooler would be beneficial.

SeeManRun

Serious question, why bother? It sounds like it will perform worse in every way; is it just the looks you are after?

500grhollowpoint

Why do it? Because my last truck had 35's on it and I thought I would do fine with the same tires in a stock size, not the case. I hit my diff and skid plates all the time trying to get in to my fishing lakes, it gets stuck in 18 inches of snow, looks have nothing to do with it.

mikeyfitz

Recommend some regearing with the bigger tires. But having 3.73s benefits for sure. Tune it and I'd say you'd be fine.

Definitely gonna take a mileage hit though, 5.4s are thirsty

500grhollowpoint

They are thirsty. I have been sitting on the fence about a programmer, my last truck was a 6.0 with a huge chip and I had nothing but trouble. Are they fairly problem free on the gas pots?

mikeyfitz

I ran a programmer on my 5.4 and now my EB since day 1 practically and have had 0
Issues. drives much better than stock

Bjg068

Whats the weight of the trailer? Pick the tires wisely. A m/t is goin to put way more UNSPRUNG weight on the rig. Id try sticking with a good a/t like toyo at2, duratrac of bfg ta ko. Obviously a 10ply e-range is what ull b into, so look at the manufaturer's specs on weights/etc. U will lose 2-3 mpg, and the truck will feel more like 3.31 range gearing. A sct tuner and custom tunes will get u back the performance. Pick a reputable vendor that does custom tunes and ull get a pkg deal on the sct and a few tunes. Load the tow tune and do a trial run w/ the trailer, u may or may not the custom tune writer to tweak the tune for shift points or pressures.

fishbones182

Dont these transmissions have thermostats in them? If that is the case then a larger trans cooler wouldnt work would it? I dont like that fact my truck trans runs 192-195 degrees at all in normal operation.