I have a stock 2006 f150 with the chrome package. I am thinking about installing a 2in AS leveling kit and going up in size in tire. Right now I am running stock tire on stock rims which is a 275/65/18. Wanting to run a BFG A/T and just wondering which is best for me far as performance, mpg, will affect my gears, wear and tear on front end, and apperance. Is anyone running this setup and if so please post pics.

 

The 285/65-18 BFG is basically a 33x11.50 while the 305/65-18 is basically a 34x12.50 tire. Both will fit/work fine, but of course the smaller tire will have less affect on your gearing, performance and MPG's.

 

i thought the 285 and the 305/65's were both about the same diameter just the 305 was an inch or so wider. im probably wrong but o well. haha

 

If you go purely by the numbers the 305 is a 33.6"x12" tire compared to the 285 which is 32.6" x 11.2". But remember each brand is different so you will need to go to their website for exact dimensions.

 

ive got a 2 drop shackles in the back, leveling out the truck. ive got 305/55/20s. there pretty damn big. nitto 420. they whine a little bit goin down the road, and the turning radius is pretty bad, but i love the way they look!

 

If your truck is 4x4 the 285s will fit w/o a leveling kit.

If you want to get the 2" level 305s would look nicer.

 

so my 305/65/17 is the same as a 305/65/18 correct? because i typed the numbers in a metric tire conversion thign i google'd and it says 32.6" for 305 and 285 is 32.8

 

They are the same width and sidewall height i believe, but naturally the 18 inch wheel give you another inch. Here is a formula for ya!
305/65/17--Ok take the first number and divide by 25.4 (=12")
Then multiply the second number( .65).. that gives you how much sidewall you have. (=7.8")
Times that by two because you want total diameter and then add the rim size to that. (=32.6)

 

Yeah the 18 is an inch taller.

305/55/20 = 305/65/18 = 305/70/17 = 305/75/16.. and so on.

 

Here, go to tire size and spec. for tire heights and size.

http://toyotires.com/tire/pattern/open-country-at

 

Did you make a decision on which to go with? Post pics when you make your upgrade!

I'm also having the same debate you are. I have a 2006 XLT with the chrome package, 5.4L and 3.55 gears. I really want the look of the 305/65/18 BFG AT but I'm thinking that I won't be happy with the truck's performance unless I upgrade to 4.10 gears.

From my calculations, running 305/65/18 with 3.55 gears should feel about the same as running 35's with 3.73 gears. The 305's reduce a 3.55 to a 3.38 gear ratio and the 35s reduce a 3.73 to a 3.41 gear ratio. I hear a lot of people run 35's with 3.73s so that tells me a gear swap for 305's and 3.55s is not necessary but would be nice so too much performance is not lost. I'm thinking that 4.10s and 305/65/18s would be a good combo. Any comments?

 

I would go with the 305's personally, my signature block has the 305s on it. The truck lost a lot of power it seemed and it had a bad shake over 65mph, I got them rotated and balanced over 5 times and still no change. So I made the decision to get 285's. Truck ran a lot smoother and had more power but i wish i would of never changed tires look real small on the truck now, the 305/65/18 are 34.7 inches tall.

 

I agree with Jordan, the 305's look great on a leveled 4x4 but you will lose some pulling power compared to the stocker's. I've been running 315x70x17's which are close to 35 inches for 3 1/2 yrs with a 3.73 rear end with no problem's other than the truck feeling sluggish. A programmer help's but is not the best fix.

 

How do you figure the 305/65/18 is 34.7" tall ?? Every formula I've seen and even the BFG website list it as 33.7" tall tire.

 

Yep^ It's 33.7, 285/65/18 BFG is 32.7.