How close is too close? UCA to tire distance

[Shaffer9]

On my stock FX4 setup the tire (275 width) is about 0.5 to 0.75 in from the UCA. How close if too close? Can I run 285s with no worries? Should I throw on a 5mm spacer to compensate for the increased tire width? Is that safe with stock stud length? Thanks for any help

 

[Shaffer9]

Any thoughts on this? I'm looking to make a plan for what we put and soon and was hoping I could make the FX4 wheels work

 

[Lou Hamilton]

Not sure what the offset is on the stock FX4 rims, but my Limited with 22s have 285s on them. I think the offset is 44.

A 285/65R18 tire is 0.5" taller than mine.

 

[Shaffer9]

Thanks for the response. Im looking at 285/70 r18s.
I think they are +44 but with the 22" wheels I would guess the top of the UCA might be below where the tire starts (inside the wheel diameter, if that makes sense). With the 18" wheel, the tire (which is there widest part) starts 2 inches lower causing a possible pinch concern.