Just ordered a 2015 f350. The only one I found with what I wanted has the 3.31 gears. I have always went with the 3.55. I don't think there will be that much difference. The most I tow is 12,000 lbs. Plus this 6.7 has 40 more hp and 60 more pounds of torque than my 2012. Any opinions? Thanks

That's a tall gear... You a flatlander? I ran an old Chevy with 307's a long time ago, rascal would stroll but was hell on u-joints! U shouldn't have any trouble unless you're running in the mountains I wouldn't think.

I know it's totally different but. My personal f_150 has 3:55 gears with the ecoboost engine. My work truck is the same with 3:15 gears. I couldn't find any difference pulling my airboat. I know it's not that heavy but it's like pulling a parachute.

It is all flat by me except once a year I take the boat to the Atlantic

I would say the ratios in the transmission will be geared to accommodate the higher ratio

I'm sure it all has to do with unloaded fuel economy set by the EPA. I know the 6.7L in a f250 with 3.55's really hauls the mail. The transmission ratios take some of that into account as well. Typically I seen the 350's have deeper ratios such as 3.73. You may want to look into it. Is it a DRW F-350?

Just picked it up yesterday. I think my calculating is correct with 3.31 gears and 18" rims that brings it up to about 3.45 ratio. I was worrying about nothing. The fukn thing flies

I have the 3:31 gears and have never wanted anything higher numerically. Mine has the 20" rims and I average 18 mpg. That is normal driving not babying it. The heaviest thing I pull is about 12,000 lbs and that is on flat ground. If you don't tow in the mountains you should be fine.

Rim size has no effect, tire size does and a 3.31 gear set still is a 3.31 gear set.

Yea. Sorry I didn't specify. The larger rim has a bigger tire. Sits 3/4".higher

You math is going wrong way. if you go from a say a 31" tire with 3:73 to a 35" tire you are going to want around a 4:10 to get you back to "stock"

Stop making me have buyer's remorse you assholes. Let my math be wrong and tell me that I am right

it will tote the mail regardless and gear sets are cheap if you want replace them as long as you do work yourself

Y'all are just splitting hairs now lol

If the truck is rated for 12,000# pull 12,000# and don't worry about it.

I pull approximately 10,000# with 3:55 gears and a gas engine. Although I don't pull it that far or that often. Never had a problem. I just pull it in a lower gear to be safe.

Yep mine looked like someone took buckshot to mine

34" tires ( factory), 20" rims , 3:31 gears. Truck is rated for 15,000 lbs so the the final drive in the new six speed must be pretty low.(higher numerically).truck is fast for a big truck but I did get beat by a 6.2 raptor the other day.