275/70/R17 Falken Wildpeak Rubbing

You just need a heat gun and a piece of wood to push the plastic back. You might need a box cutter or file to trim the front plastic. I have 34s now.

 

It depends on where the movement occurs. Stock trucks only pivot at one place, at the bottom ball joint via the 2 adjustment cams on the back and the front of the lower control arm. These change both caster and camber at the same time. Pushing the LCA forward towards the front bumper, moves the lower ball joint forward of the lower ball joint, creating more POSITIVE caster (picture motorcycle chopper).Conversely, pushing the LCA back, towards the cabin, creates more NEGATIVE caster, as it moves the lower balljoint directly underneath the lower balljoint (0* caster - picture a shopping cart caster) or behind the upper ball joint (negative caster)

Now, with movement forward or backwards at the upper balljoint, whether adjustable or Built in caster, the opposite occurs. So when you move the upper ball joint position forward, toward the front bumper, it moves directly over top (again 0* caster) or forward of the lower ball joint, creating more NEGATIVE caster . When you move the upper ball joint back, towards the cabin, it creates more POSITIVE caster.

So, to create clearance at the cabin mount, you want to move the wheel asy forward, in one way or another or both, BUT you could end up negating one adjustment (or position) at the upper ball joint with the other, at the lower ball joint. For example. With your control arms, which are exactly like mine (Blackhawk UCAs) which add caster by moving the upper ball joint BACK towards the cabin, which increases caster +3* BUT, since you moved the wheel back towards the cabin, it might rub. Since the rub happens at the bottom of the wheel well, and technically you pivoting more of the top of the tire back it may not rub. Mine does a teeny bit and I have over 4* caster. I did have over 5* caster but my wheel felt really heavy, which is a by-product of too much caster on our trucks so I settled at 4* with a teeny bit of rub when backing up and going down the driveway.

To fix this, I'm probably going to get SPC UCAs which have caster and camber adjustment at the upper ball joint. What I do, to make it easier for the tech at the shop, is set to lock the upper ball joint caster setting at "E" or "F" to get the minimal caster correction at the UCA without moving it back too far to the cabin then dial in the caster (and maybe the camber) at the lower control arm. You have to tell the tech about the camber setting on the UCA so he can even that out side to side first using an alignment machine (unless you have the right setup at home) FYI, the setting of the UCA is dependent on how high you lift is, the higher the lift the more negative the caster goes and the more positive the camber goes.

SO, what I do when I install the SPC UCAs on my truck, because I have minimal lift (2.5") I will set the UCAs to the "E" setting (+1* caster) and eyeball the camber and lock in the UCA temporarily. Then set the LCA to the center of range equally on both sides and lock that in. Then take it to the shop and tell them to even out the camber at the SPC UCAs first and lock that in then, fine tune the caster and camber with the LCA cams, to get around +3 to +3.5* caster with +.5 degrees camber. I also like to ask for a little less caster on the drivers side -.3 to -.5* to compensate for road crown.

Sorry for the long explanation. I see a lot of confusion with this with people just saying "add caster to clear larger tires" which is not necessarily true. Add to that how caster is introduced with UCAs it can be confusing

 

I'm lifted on 5100s set on the top setting, stock coils and a 1 inch rear block, stock mud guards were a must keep and 285/70/17 on Pro SEMA wheels with stock upper control arms and no rubbing, cutting or trimming at all. I was on the 4th setting right after the tires were put on and rubbed a few times in reverse going up a steep driveway. I had the shop that did my lift 4 years ago bump it up up to the 5 perch and re did the alignment, its good to go now. Flexed it a few times and for my off roading adventures I should not have an issue.

 

Yo. Same exact issue, that you went through, and I was just curious how things held up? If I trim that same spot, use the heat gun and push the plastic back, I’m also going to have a slight rub on the body mount as full lockout.

So, I was curious if that became an issue for you or if you ended up making other changes.

thanks!