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2014 Ford F-250 6.7L
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Discussion Starter · #1 ·
Currently running a ReadyLift 2.5" spacer level on 35x12.50x20 Toyo AT2s. It looks good but the tire doesn't fill the wheel well as much as I'd like it to. I'm switching to a Carli Suspensions 2.5" Coil Spring kit. I'm going to get the Toyo AT3 and keep them on the stock 20" Lariat wheels.

So.. stick with 35x12.50x20? or go to a 37x12.50x20?

I've seen people running 37s on a 2.5" level and it sounds like it just rubs the inner radius arm due to stock offset rim.

Anyone done this here? Post pictures if possible? Thanks
 

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Well before youi buy these tires make sure you can adjust the permeates in the truck for that size tire. Ford limited the size tires in there strategy. You may have to plus size them.
 

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Yeah, you'll likely rub the arm. Definitely will if flexed at all. I think it'll rub the fender liner up front also. Gears are another thing to think about. If you have 3.55s then 37s will make it feel sluggish IMO. Great fuel economy though. Lol. I have 3.73 and 295s and I wouldn't go up in size without swapping to 4.0 or 4.3 gears.
Well before youi buy these tires make sure you can adjust the permeates in the truck for that size tire. Ford limited the size tires in there strategy. You may have to plus size them.
If I recall correctly, the tire size can be changed to almost any diameter by using an equivalent metric ratio. So for a 35x12x20 you'd have to figure out the metric size for a 34.5" tall tire. I did it for my 295's and every radar speed sign is spot on (unless the random one is way off). Also speed trapped it at the race track.
 

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12.5 wide on a stock wheel will rub no matter the lift. If you want to run 35s or 37s with a 2.5 lift you're gonna rub unless you get specific spec wheels and trim a little.
 

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Yeah, you'll likely rub the arm. Definitely will if flexed at all. I think it'll rub the fender liner up front also. Gears are another thing to think about. If you have 3.55s then 37s will make it feel sluggish IMO. Great fuel economy though. Lol. I have 3.73 and 295s and I wouldn't go up in size without swapping to 4.0 or 4.3 gears.

If I recall correctly, the tire size can be changed to almost any diameter by using an equivalent metric ratio. So for a 35x12x20 you'd have to figure out the metric size for a 34.5" tall tire. I did it for my 295's and every radar speed sign is spot on (unless the random one is way off). Also speed trapped it at the race track.
I believe others have tried to change there tire sizes only to find Ford limited the size of tire you can change. You need to get this correct or the computer will go nuts and the ABS will apply brakes speedo will be off and transmission will not shift correctaly. Before spending this mon ey on biger tires. he should talk to a tire shop to see if they can program his truck. maybe talk to the dealer.
 

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The dealer won't be much help if it's not a factory size.
Most people forget to set the BCM and TCM into "learn" mode after changing the size. That is what sets the TC and tranny into fits. There is a spreadsheet in Google Drive with the constructions on converting the size to HEX and where to put it in the BCM config.
 

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Did they every nail down those conversions? I haven't followed it much since the factory sizes worked
 

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Discussion Starter · #8 ·
12.5 wide on a stock wheel will rub no matter the lift. If you want to run 35s or 37s with a 2.5 lift you're gonna rub unless you get specific spec wheels and trim a little.
What size lift and rim/tire combo are you running? Love the look of those Toyo MTs and Methods. 35s/18s?
 

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Discussion Starter · #10 ·

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2013 F350 Long Bed 4x4 Lariat
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You will rub on the radius arms and the front bumper brackets and valance. I ran 37's on the factory wheels for a few weeks before getting spacers and then ultimately went with an aftermarket wheel with more negative offset. The factory wheels are 8" wide with 40MM of positive offset which is roughly 1 1/2" from center. If you add 2" spacers you turn that into -10MM of offset if you were to run the same size wheel. This will put you out enough not to scrape on full turn until you get into situations where the vehicle is uneven such as pulling into to driveway at full turn then depending on how the suspension is flexed you will rub again on the bumper brackets or radius arms. With a 9" wide wheel which is a pretty common after market width for 20" wheels you will want to get a 0MM offset. This will put you out just a tad further than what a 8" wide with -10MM will put you at. You don't want to go much further negative than this though unless you're going to lift it up more as you will start rubbing again but on the opposite sides from before like the edge of the bumper and rear body pinch welds. I'm currently running a 20x9 0MM with 37x12.5's and they work great I get no rub and can still pull my 5th wheel. Disclaimer though I did trim my valance up a bit when I first installed the 37's. Here's what it looked like with the factory wheels and spacers and what it looks like now with the aftermarket wheels for reference and how far they stick out, I didn't want to stick out to far but still wanted a more aggressive stance and I think both looked great, If I wasn't so worried about towing with the spacers I would have left them as I actually really liked the look with the factory wheels. I don't think I have any pictures without spacers on factory wheels but I didn't like the look of such a big tire being pushed so far under the truck it looked strange to me. Also forgot to mention I do have 2.5" leveling spacers up front with Carli castor correction shims.

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