285s / LR UCA Alignment Question

[RyanCocolin]

I posted about a week ago on this issue and got some good advice, but now I'm trying to 1) better understand alignment and 2) figure out what I need to talk to the alignment shop about when I drop off my truck.

I went from stock to 285s a couple of weeks ago and haven't gotten a new alignment yet. I'm rubbing on my body mount on one side and on the other side I hit the fender (see pics) before I even make it to the body mount and before I'm at full lock. I'm doing the body mount chop as soon as weather cooperates and I have a body lift on the way, so now I'm looking into alignment. People seem to have the same set up and don't have anywhere near the issues I'm having so I'm hoping alignment can fix most of it. BMC and fender liner seem to be the only things people need to do to make these tires fit.

I've read as many posts as I can find but I find contradicting info everywhere. Some people with my same setup (285s w/ -12 offset wheel w/ 3" lift) say get 4* caster and that will push the wheel forward and pull it off of where I'm rubbing. Some people on Priate 4x4 say that larger tires require reducing caster (I could see how this may push the wheel down as the caster angle gets closer to 0*)

I looked at my UCAs and I get even more confused with this stuff. My Driver side is in the D Position which should give an additional +2 caster but my Passenger side appears to be in the A position which provides +4 caster.

Also, the pic below shows my alignment specs pre tire upgrade. i have +3.2 (D) and +3.5 (P). Does it seem odd to anyone else that with my UCA in a position to provide +4* I'm only at +3.5 on my passenger side?

And if it's not already obvious, I have no clue what I'm talking about so feel free to set me straight. Thanks in advance!

 

[montijo505]

Have them set both of the UCA's the same and then get the alignment in spec, the reason you're rubbing on the fender MAY be because they're set at different angles.

 

[gm350reratliff]

Looking at those pics, the BJs are set different from side to side. So in order to get caster to match side to side they probably had to adjust the LCA cams very different, which may explain some of the rubbing and why it rubs differently on each side. I would recommend what [MENTION=109843]montijo505[/MENTION] suggested and install the BJs exactly the same on both sides (I would start with the 0 or +2 setting) and go from there. How much lift are you running? What wheels are you running? Spacers?

As a side note, most mfgs design the suspension (usually at least the front) so that camber, caster, and toe, to have the ability to be adjusted a certain amount in order to make the vehicle track straight and drive good. They don't design it to be adjusted so you can fit bigger tires without trimming. Yes, maxing the caster out by adjusting the rear LCA cams all the way out will net you some room but you shoudn't count on it especially if there is a huge caster split or it creates a camber issue. Too much caster can also make the tires "scrub" more on turns which can wear them down faster. It also varies truck to truck. Some get by without any trimming and some need a bunch of trimming.

 

[LTDSC]

Looking at those pics, the BJs are set different from side to side. So in order to get caster to match side to side they probably had to adjust the LCA cams very different, which may explain some of the rubbing and why it rubs differently on each side. I would recommend what [MENTION=109843]montijo505[/MENTION] suggested and install the BJs exactly the same on both sides (I would start with the 0 or +2 setting) and go from there.

This, why didnt you match them for equal results?

 

[RyanCocolin]

This, why didnt you match them for equal results?

I didn't do the install and had stock tires until about 2 weeks ago. Nothing was an issue until the bigger tires and then I started looking into what could be the problem. I'm really not sure why the guy who did the install set them up so differently.

So today I went to several places and none would touch the UCAs. I was trying to get them to set both UCAs at the D position and then work the alignment into spec from there using the lower ball joint - all I got was a blank stare. So I went to the local Toyota dealership and sat down with two techs. I explained my problem and what I thought needed to be done. They were awesome and spent about 5 hours on my truck adjusting the alignment and fixing the rubbing issues. So now I have zero rubbing on Body Mount/ fender and I'm within alignment specs. It all worked out and as of now I don't need to do the body mount chop or install the body lift. And I actually ended up losing a degree of caster on each side versus what I thought needed to be done.

 

[LTDSC]

glad you got it figured out.