Hello All,

I have an '02 F250 7.3 Lariat 4x4 Supercrew with worn U-codes that I am installing OEM X-Codes on front. I currently have the factory 16x7 lariat wheels with 285/75R16s on them.

I have a brand new set of X-code springs from Ford that I am installing this week, so should get some lift out of them.

I have a set of 18x9 wheels with 0 offset/5" backspace that I was planning to use.

My concern is whether a set of 275/70R18s will fit with the lift from the x-codes will fit/rub/etc. I have read that 305/60R18s will fit without level or lift. The 275s will be about 3/4 an inch taller and 1.25" narrower.

I want to try and make sure before I buy the tires.

Any thoughts?

Thanks,

Bill

 

Those 275's are only .33" taller (on the calculator) than your current tires so you should be fine.

 

I'd double check the back spacing part. I recently got new wheels for the wife's truck running 35's with a 4" lift. The 18" wheels she wanted came with a 5" back spacing. The 17" wheels we bought had a 4.5" back spacing.

Smaller tires might be OK, but I'd worry about hitting the springs at full lock. Do the 285's rub any at full lock now?

 

I realize that there is not much difference in size from the tire size I have now. My concern is the difference in the wheels. I currently have 16x7 wheels 0 offset/4.5" backspace (per chart I found outlining wheel size and backspace). I am looking to use 18x9 wheels with 0 offset/5" backspacing (per manufacturer website).

My concern comes from the additional backspace and width of the wheel - essentially sitting 1.5" further in.

 

On the 16x7 wheels, the current tires do not hit the springs, however my concern is with the wider wheels that a comparable size tire might.

I just measured the backspace of the replacement wheels by placing a level across the back of the wheel and measuring to the mounting surface = 5"

 

I share your concern. I can tell you that my wife's truck with stock wheels and 285's would just rub the wheel well liner and every once in a while touch the springs.

I talked to enough people that with her current 4" lift, we shied away from the 18" wheels with a 5" back spacing due to concerns about it rubbing.

I'd suggest you measure clearance from the wheel well liner and at the springs with your current set up. You should be able to do the math based on the new vs. old tire width and backspacing to answer your question. I'm guessing you don't have a lot of space to work with now.

 

I think that I will hold off on ordering tires until I get the new X-codes from Ford installed on Friday.

Once they are installed, I will put one of the "planned" replacement wheels on without a tire and measure spacing when at full lock in both directions - measuring to spring, bumper, and wheel well. I think at that point I will be able to determine with fair certainty what size tire would safely fit based upon measuring from left, right, and center of wheel when turned in each direction.

I really do not want to go the spacer route, so if it turns out that the wheels will not work, then I will just put them up for sale (and take some grief from the wife for getting them - luckily used and half retail cost).

 

I am thinking of doing the same thing on my 350. Can you post up some before and after pics? With the 285s?

 

I replaced my worn V-codes with new OEM ones several years ago and the front end sat about 1" higher with the fresh spring packs on there.

 

I neglected to get a photo prior to replacing the springs, but here are the measurements from before and after:

Before:
FL - 38.5 RL - 40.5
FR - 37.75 RR - 40.5

After:
FL - 40.25
FR - 40.25

Here is the after picture with 285/75/16s that are worn out (almost to wear bars).



Next week I should have the new wheels and tires on. After measuring movement of the new wheels, I think I should be OK with 275/70R18s.

 

Another thing to consider is tread pattern size and not just tire size. As an example, I replaced my wheels and tires yesterday. I was worried that the new wheel (4.53 back spacing) was going to rub more than my current wheels that had a 4" back space. While I went with the same tire size (37x12.5x17), the new tires only have about a 10" tread pattern over the 12" on the old tires. With the new wheels and tires I no longer hit the leaf springs on full lockout even with an increased back space on the new wheels. This is the difference between a Pro Comp Xtreme A/T (top pic) and the new Pro Comp A/T Sport... Both are marked as 37x12.5x17

 

Well, the new wheels and tires are on and fit without issue, even at full lock in both directions. I might have to be careful with turns and bumps since the closest point is about 1 inch.

This is with the OEM X-Codes from Ford, 18x9 wheels with 0 offset and 5" backspace running 275/70R18 Goodyear Duratracs.