UCA Install + Alignment = Rubbing

[vitruvius]

Wrote a long post only to have a "page cannot be displayed" bite me in the ass.

UCA installed caused some rubbing which I expected, but after the truck was aligned, it started rubbing the cab mount in the back of the wheel well.

Truck was aligned to these specs:

Caster: 2.4*
Camber: -.1*
Toe: .04*

Both right and left sides match perfect.

If you look at the truck from the side, with the wheels pointed straight ahead, it looks like there's about 1 inch of clearance between the fender flare and the tire in the back, and about 3 inches in the front.

Seems like the caster angle is too steep and is pulling the tire back in the wheel well. If I increase the caster, maybe to 4*? Think it would bring the tire back into the center of the wheel well? Any advice? Thanks!

[vitruvius]

Anyone got any advice?

[toku58]

Originally Posted by vitruvius

Anyone got any advice?

Your specs all look good!
How big are your tires? And do you have a lift?
Sorry! Just checked you Cardomains.
Your ires should clear? But obviously it doesn't.
The specs you have are exactly the same as mine.
And my rims only have 2 1/4" BS so if anything mine should be worse than yours.

Do you have better pics of your set up?

[toku58]

Here is a picture of my truck from the side:

I have more than enough clearance from the rear and the front fenders. I have at least 3" front and back

Can you post pictures of your UCA's I would like to see their orientation.

Your tire should NOT have moved so far to the rear.

[vitruvius]

I'll take some pictures later today, still haven't figured it out. Best guess is the caster but we'll see.

[vitruvius]

[vitruvius]

Toku, help!

[Adventure North]

I'm going to say too much caster for the amount of lift you have. When it comes to lift and alignment specs one size certainly does not fit all. What are you sitting at? 2 - 2 1/2 inches of lift with the 884's?

[vitruvius]

Just shy of 2.5" in the front, so you're saying I should probably increase the caster angle or decrease?

From what I understand, if I increase the angle, the tires will move forward more, angle moving from verticle to horizontal.

Decreasing would move the tires even further back, increasing rubbing and moving the angle from horizontal to vertical.

So I should increase the angle of caster in order to solve my problem? And if so, by how much? It's at 2.4* now, should I try 3*, 4*, 5*? I don't want to have to pay for an alignment 10 times, but also don't want to over shoot it.

[tacogrande]

Read this, it should help you explain what you need to the alignment guy. Just because you are "within specs" doesn't mean you can't move your tire further away from the body mount and get the exact same numbers. http://www.*******.com/fsm/05+/data/...a/03900310.pdf

I would start by turning your rear cams to + until your tires clear, and then dial everything else into those. There's lots of adjutment, don't worry about maxing anything out.

[vitruvius]

I understand what you're saying, and I shouldn't have a problem explaining it as long as the guy "wants" to understand. He was cool about it last time so hopefully he can help me out. Going to have him set it up to the maximum amount of tire clearance and then dial in the alignment angles from that point. Thanks for the help, we'll see what happens.

[toku58]

Originally Posted by Adventure North

I'm going to say too much caster for the amount of lift you have. When it comes to lift and alignment specs one size certainly does not fit all. What are you sitting at? 2 - 2 1/2 inches of lift with the 884's?

+1 Agreed you don't have enough lift for the size tire!

Your tire are too large for the amount of lift you have.

Measure you height from ground to bottom of the fender, through the middle of your center hub. Should be about 39" with those tires. Mine is about 39.25".
Where is the top spacer plate??

Just to clarify: If you use the stock UCA's with 2.5" of lift you can get away with 285's but you alignment will be set at towards the MINIMUM spec range.

To be able to set it to the IDEAL alignment settings with 285's you will need a full 3" of lift. ("Ideal" is mid point of the Min. and Max. of the spec range for your alignment)


So either you set your truck more towards the Minimum which would make the cost of the TC's sort of a waste. (Because your truck will not get the full benefits of the UCA's)
Or install the top plate to give you better clearance. the 1/2" top plate will lift your truck an additional 3/4". That way your front will become a bit more level with your rear.

Good Luck!

[Adventure North]

A typical lift really has nothing to do with the ability to fit a larger tire. Should a "lifted" suspension be cycled it will still move through the same plane as it did stock. Reality is increased fender clearance by way of trimming, wheel offset and relocation of the bumpstops are what allow for a larger tires to fit properly.

[toku58]

Yes AN is correct. But I guessing that because of the lesser lift it has caused your caster to move too far back. When you lift it higher you caster will be over the 2.4*.
Here are pictures of how my wheels sit:






My tires sit almost perfectly in the middle of my wheel well.
Rubs slightly only when the wheel gets jammed up in the fender while I'm reversing and turning.

[hyperlitewkbrdn]

wow i havent been on here in forever, thought id chime in on this one.

i have the 884's with the 1/2" spacer and i have had the same problem as vitru for a few months now. it rubs on the metal bracket towards the rear bad. i'm wondering if its because of the 884's but i dont know. the reason for this is because it rubbed on the front before i got the tc uca's. once i got the uca's and increased the angle, it seemed like it pulled the tire back. it changed from like .8 to 2.4 i think and now it rubs on that back bracket instead of the front fender. so maybe the angle should be decreased????