Dobinsons UCA w/ 285/70R17 experience?

I found very few posts from people using Dobinsons UCAs, and none that mentioned this tire size.

I bought this truck with a 3 inch spacer lift the previous owner had installed. It has 285/70R17 and SCS Ray10, 17 X8.5 wheels.

The front tires rub the rear of the wheel well when hitting a big dip on the freeway. I’m currently leaning heavily towards buying Dobinsons IMS struts, but my question is specifically about Dobinsons UCAs.

Anyone running this tire size and Dobinsons UCAs? I’m curious if real world experience shows that they move my wheel forward enough to not contact the body, or if I really need to be buying SPC UCAs?

This truck is not my primary wheeling vehicle, so I’d prefer to try and fix the tire rub with suspension rather than BMC.

 

I would recommend high caster UCA’s such as JBA it will give you the biggest chance of not having to do a BMC

 

That's just the opposite. High-caster UCAs move the upper balljoint rear ward, and the tire closer to the body mount. More caster achieved through *LCA* cam bolts improve tire clearance.

 

High caster means a higher range or settings of caster whether that means positive or negative I belive the JBA’s max up around 4% and you would want positive caster to push the wheel forward in the wheel well

 

That's just the issue. Positive caster only pushes the wheel forward if it's achieved through LCAs. Positive caster achieved through UCAs pushes the wheel rearward. Anyway the "high caster" JBAs give +3 deg of caster, same as Dobinsons (which does make the JBAs a better deal).

 

@s.wilson if you're currently running stock UCAs and rubbing the body mount, then any aftermarket UCA except SPC will make it worse.

Most aftermarket UCAs are designed to add caster to reduce steering wander when lifted, since the inclined UCA hinge line make the stock UCA lose caster when lifted.

 

Ah, thanks for clearing this up for me!

 

The only UCA that will move the wheel forward, away from the cab mount are adjustable UCAs like SPC.
Aftermarket UCAs with built in caster are always positive caster which pushes the wheel further back towards the cab mount.

It blows my mind about how often this is wrongly posted all over TW.

In reality unless you get adjustable UCAs, the stock UCA will clear bigger tires better than the aftermarket ones because they have positive caster built in.

To move the wheel forward you need negative caster on the upper control arm and/or positive caster on the lower control arm.

 

THIS^


I say start cutting lol

 

I have 285/70/17 with no cutting and no trimming.

The real secret is to get adjustable UCAs and make sure that your wheels don’t have too much offset/backspacing.

It seems like adjustable UCAs and wheels that are 12mm offset and 4.5” backspace is about perfect if you want a little poke without trimming/cutting.
This is the setup I have.

 

So what uca did you end up going with ? Was it the dobinson uca or spc uca? Did it turn out well ?

 

I know this thread is 2 years old. What was the outcome OP? I have Dobinsons 3" lift with their UCA's I intend to install 285/75/16 on factory rims. Has anyone had success with sufficient clearance using Dobinsons Uca's or is SPC the only solution?

 

Um no. Positive pushes the wheel toward the front. Negative toward the back. Don’t believe me? Call all the manufactures. They ain’t dumb. They make them to clear bigger tires. I even talked to Miquel from Mudify about it. He said that UAC with built in caster push the wheel forward away from the body mount. So for up to 33” that’s good. If you go bigger you need more caster adjustment hence why SPC would be a good choice. What many are hung up on is the fact that the UAC shows the ball joint further back (negative) which pushes the wheel forward (positive) due to the way the IFS is designed.

 

I suggest you call Dobinsons. I just did that myself for a question about coil springs. No point in discussion this with ppl on a forum because you never know what level of knowledge they have.