After market UCA's???

What is the purpose of UCA's?? I know some install them when they add a lift kit. I have added bilstein 5100's front and rear. Raising front 2.5 inches and OME leaf springs in the rear which seems to have added 2.5+ inches. I like the results but wonder if I need to add UCA's. I have 265-75-16 and plan to add 17" wheels and tires but will only raise another 1/2-1".

Mainly just want to know what the UCA's do. I did search for this but got hundreds of answers.

thanks

 

The more you lift, the more the tech's can't adjust the stock UCA for camber and caster I believe. The Tech that did my truck also owns one he's working on. He suggested these.

 

Tacomas have adjustable lower control arms, to introduce positive or negative camber. When you raise the front end, the wheels will "bow out" (top of tire sticking out more than bottom of tire, not perpendicular to the ground). This of course happens with any vehicle that as an independent suspension.

The lower control arms can only be adjusted so much, because Toyota isn't in the business of supporting lifted trucks ... the easiest solution is a replacement upper control arm that's "wrong" geometry for a truck at original height but correct geometry for one that's been raised. This permits adjustments down at the LCA to meet not only a camber spec that's within acceptable range, but the ideal number.

With a 2.5" lift, your camber spec is likely at or within range of being "OK" but is no longer ideal, with more positive camber than intended. The result is a truck that can't corner as smartly as originally because the outside tire (which will be the most heavily loaded laterally when turning) will always be leaning away from the direction of the curve, not into it or at least more upright. This could also cause the outside of the tire to wear excessively.

Some of that's hypothetical and not an emergency per se. Would you be better off with an aftermarket UCA? I think so, but ask around!

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I have 265-75-16 and plan to add 17" wheels and tires but will only raise another 1/2-1".

The tire is irrelevant, since the suspension doesn't know anything about the sidewall height.

 

They're mainly to get your alignment right. A lot of people say 3" or more, you'd need aftermarket UCAs, but if you can't get your alignment right, then I would suggest to get them