I pull a 5100lb (dry) 7800lb (gvwr) trailer. I have a 2004 F150 FX4 with a 5.4l V8, 3.73 gears and an Edge Evolution programmer. I can pull the trailer OK right now, I wont be winning any races mind you, but I want a bigger beefier looking tire. I presently have 275/65 R18 Copper Discoverer STT's on the truck. I want to go to 33X12.50 R17 Cooper Discoverer ST's. I want to know what you guys think about that. The tire itself is only about 3/4 of an inch bigger but I need to know will I notice a difference towing and will I notice a loss of power to the larger wider tires? If you have these tires on your truck let me see a couple of pics. I do a little offroading with the truck and have actually owned these tires before on a Dodge 1500 (I know, I know. Recently converted to Ford) and know they are an awesome tire. Let me know what you think. Will there be any noticeable difference in performance.

Thanks in advance guys.

 

I had 33's on my F150 with a tune for towing and I could tell I had some power loss when towing a trailer. If you tow often I would recomend staying with the stock tire size.

 

Get 4:10's on your truck

 

If you are "OK" now with towing, going to the taller tire will effect your overall effective gear ratio, so you might notice that it won't hold 3rd as long on the grades, or it might even slip into an unlocked TC condition while still in third, and that will cause the trans fluid to heat up considerably..

Sounds like you are also wanting to go wider on the new tires, so that's going to cause some extra rolling resistance and weight to the whole deal..

I've only got 3.55 gears, but the stock tires were 255/70/16 and I went to 265/75/16 and could tell a big difference... I had to recal the speedo/odo to get the trans to shift right again and I only tow a #5000 GVWR trailer, but I feel I'm maxed out on my 3.55 gears...

If you got some 4.10's like Slammajamma suggests, you'll basically bring yourself back to where you are now for the most part..

Give and take is what you have to deal with in this case...

Mitch

 

The problem is more weight than tire size. That's only about 3% larger tire so 3% less torque you would rarely notice. I don't like my truck's power with heavy 33" tires without a payload or towing. If/when I replace them, it will be lighter ones.

$1500 gear swap to 4.10 is not worth it. If you swap gears, go 4.56.

 

No imput, just here to say a Saskatchewan 'Hello'!