I think one member managed to squeeze some 315's on a 4x2, but that probably didn't last too long. Mine are close in the front on my 4x4.

 

2005 STX 2WD with 295/70/17

 

since im in the same situation, i was wondering the same thing. but i have an 06 xlt supercrew 4.6 v8..i have 285/70/17 with a 3 inch body lift i was wondering how big i can go without rubbing and any mods? plus i dont understand the whole 285=33's? i thought 33's were 33's lol n so on ..help plz

 

I would think you wouldnt want to go any bigger than a 305/70/17. 295/70/17 or a 305/65/17 would be good choices as well.

In a tire size that is not listed as the "flotation" size i.e. 33x12.50R17 would be a 306/65R17. The 305 is the width of the tire in mm, the 65 is the aspect ratio which is a % of the width (.65x305) and it is the sidewall height.

here is a good conversion tool.....
http://www.1010tires.com/TireSizeCalculator.asp

 

To calculate tire size yourself is pretty easy. take the width (285) divide it by 25.4 to convert it to inches. 285/25.4=11.23. then you take your width and multiply it by your aspect ratio (70) to get the sidewall height. 11.23x.70=7.87 Then you take your sidewall height and multiply it by 2 because you have two sidewalls included in the diameter of the tire. 7.87x2=15.74 Last you simply add the diameter of the rim and thats your diameter. It probly seems complicated but after you do it a few times it is very quick and simply. You dont need to rely on a computer to do it for you. here is a recap...

285/25.4=11.23 Convert to width from mm to inches
11.23x.70=7.87 multiply widthxaspect ration to get sidewall hgt
7.87x2=15.74 sidewallx2 to get thickess of both sidewalls
15.74+17=32.7 rim dia+tire sidewallsto get overall diameter

 

yeah you are right you don't have to rely on a computer to do it, but why not if it saves you time, I mean you have to use a calculator to do it the other way.......but I mean I guess if you weren't at a computer and had that formula memorized.........

 

ohhhk...i got it noooww..i didnt expect such a good break-down, thanx alot, so if i want wider stance...like a tougher look....i would get...?

 

what about a leveled 4x4? I'm curious what the largest tire that would fit the rim itself is - would the 315/70/17 fit the 7.5" wide rims? On 1010tires's calculator that comes up as 8.5-10" rim width recommended...

anyone try that yet? I think andrzej77ff's truck has the biggest tire i've seen on a stock 17" rim so far... anyone that went bigger ?

 

I dunno about the other posts in this thread. But I am speaking from PERSONAL experience.

2004 - 4x2 XL 4.6 Short Bed, Reg. Cab. AS 2.5 Leveling kit with BFG AT315/70/17 on stock 17" XLT Rims. No issues at all.

2007 - 4x4 XLT 5.4 SuperCrew 6.5 Bed. Bilstein 5100 Preload adjustable shocks. BFG AT 315/70/17 on the same rims. No issues at all.

Pictures are in my Gallery.

 

nice.. you have the same rims I have so i guess that answers my question. Wonder if the KM2s fit the same way as the TA KO's... or the kumho roadventure MT's... In the mustang world, BFGs tend to run larger than Kumhos in the same size, does that hold true here?

 

A lot of people run 315's on the stock 7 1/2" wheels, trying to get somone to mount them may be a little tough!

 

i thought the same thing, but that little engine has got some power...i am running 35s...and no complaints yet...

 

Just goes to show that every is different. I wish my 5.4L 3.73 gear with 33" tires had more help.

 

I put 315/70/17 with stock wheels on my stock suspension 4x2 2007 f150 , i removed the front bumper plastic and i was fine it still rubbed a little at full left turn i now have a pair of fuel wheels on it with a 15- offset and they dont rub at all !! So yes it can be done , wish there was someone that did it before me but i have found no help before so i just did it ! I have a 5.4 v8 in it and its very noticeable in power wise i'd say its 30% slower than with my stock 255/65/17 tires