Mr. Ford-Man

BFG 34X10.50R17 on a 2013 F150 Regular cab, 6.5' bed 4X4 3:55 gears 5.0L

Hey guys! I have been researching the site for help. From what I gather I will see a little power loss with the 34" tires and a loss in fuel economy.

These are the tires I want to run: http://www.bfgoodrichtires.com/tire-...2/tire-details

Question 1. Will the narrow 10.5 "pizza cutter" tires help keep the decrease in MPG to a minimum? The truck is rated at 14/19 MPG with the stock 235/75/17 tires (30.9X9.3R17 equivalent) How much drop in MPG should I expect?

Question 2. Will the 5.0 regular cab 4x4 truck become sluggish since I would be keeping the 3:55 gears? The truck is a little lighter since it is a single cab so maybe that will help maintain the power? (I cant afford to swap gears)

Question 3. Will the transmission get out of wack by jumping up 3" in tire height or will I notice little to no change? If so will I need a tuner or a ford dealer make the changes to the computer?

Question 4. Will the 10.5" wide 34" tires clear on the front end without a front end leveling kit?

Thanks for any help

Sirikenewtron

I'm getting those same tires, same size. You're going to loose some mpgs for sure but those tires are D load so they are 55lbs, not as heavy as most 34's and a lot of 33's for that matter so that will help.
Since you have the smaller stock tires to begin with you will probably want something to adjust the computer/transmission for your larger tires, tuner would be your best bet.
I have 2" of lift up front and 3"rear blocks, I don't think the width will be an issue for you but height might be if your truck is stock height. The 34x10.50's ko2's actual height comes out to 33.5"

Mr. Ford-Man

Thank you for the reply!

I have read of owners pulling off 34" +/- .5 tires on stock height 4x4 f150s in some of the other threads. I will keep my fingers crossed.

I have an SCT tuner I had used on my Bullitt Mustang that has the factory tune returned to the Bullitt that I could use on the 13 F150. I think it is the past generation handheld from a couple of years ago. Can anyone recommend a good company that could give me a correct transmission tune that will get it back to stock if I swap out to the 2.5" taller 34" (33.5") tires?

Would any of you recommend a tune for the engine performance as well or will it void the powertrain warranty?

egfarmer

a 10.5 34 should be okay on a stock 4x4 truck. They will be "stuffed" but shouldn't cause too much trouble. Where most people run into trouble, putting big tires on stock trucks, is that the said tire is a 12.50 wide tire, which rubs all the inner wheel well components. You've eliminated this problem, or atleast decreased the likelihood of it happening, by going with a 10.5 tire.

Sirikenewtron

Did you ever get these Fordman?

Mr. Ford-Man

Ended up buying a brand-new 14 Tremor 4x4 off the dealer lot last month Love it!!!

4.6Intruder

I have 285/75r17 which is a 34x11ish tire. 75-80mph down interstate I average 15-16mpg as long as there isn't a strong head wind. 50-65mph highway driving I get around 17-18ish mpgs. With a 1.5" lift I had to trim front valence and pull the front wheel well liner back to clear lock to lock, but I also have aftermarket wheels with 0 offset. With that said, I don't think a 34" even a narrower 34" on stock wheels and stock height will clear without trimming.


I also have 3.55 gears and honestly didn't notice as much of a performance lost as I thought I would. I have no issues breaking the tires loose. I have an SCT x4 loaded with custom tunes from 5star and MPT. Different tuning strategies so can't compare them equally, but my 5star tunes are perfect for daily commuting yet still provide plenty of get up and go and like there shifting strategy. Your speedo will be incorrect obviously so shifting may be out of wack. Tunes and warranty are an iffy subject. Anything engine related or drivetrain related, they can void your warranty since they can say it was the tune and they are able to tell if anything has been changed regardless if you change it back. Anything none drivetrain/powertrain related will still be covered. Technically with oversized tires they can claim it caused the issue if you have a drivetrain/powertrain related issue since they are heavier. How likely are they to do that however is not very high depending on dealer.

150FX4ever

How do you like 5star vs MPT? I have 5star loaded now but I have MPT that are made for use with a set of Catless downpipes I haven't gotten around to installing yet so I haven't gotten to load them

4.6Intruder

I can't do a completely fair comparison between the two since they are setup for different applications. I have 87, 89, and 93 octane performance/tow tunes from 5 star. From MPT I only have 93 performance "street" and "race" tunes. My MPT tunes I feel does a better job as far as performance gains go at least how it feels. Shifting is spot on and much firmer which I like. May end up getting the 87 performance tune from MPT since gas is pretty cheap now.

The Bombdiggity

Hey there Mr Ford Man, I just bought some 34's for my 2014 4x4. Spec is 305/70r17 BFG KM2 mud terrains. I have aftermarket wheels too 17x9 with -6 offset. I had to do some minor trimming but nothing extravagant. I think you'll be fine on the clearance of your fenders. My mpg hasn't gone down a whole lot maybe at most 2mpg drop. I bought a Hypertech Speedo calibrator as well and noticed that my RPM's are a little lower as well running the taller tires. Good luck to you bro and hope this helps