Would aftermarket UCAs improve the ride significantly?

My rig:
2018 SR5 prem, TRD wheels 265/70 R17 wildpeak tires (do not want to go bigger). Eibach Pro Truck lift kit.

Currently I am running the factory UCAs, my driving is 95% around town / highway. When I've taken it off road, it has been the "easy to moderately easy" stuff. All in all, the ride of the 4Runner is very good, better than when it was stock.

I am trying to decide if aftermarket UCAs would improve the ride "significantly" or would I be spending the money just to get "cool looking UCAs". After alignment camber was 2.8 degrees left and 2.9 degrees right. Seems to me the swapping out the UCAs may allow for more camber, but with the type of driving I do, I may never notice it.

thoughts ????

 

The only reason you would want an aftermarket upper control arm is if you lift beyond the alignment capabilities of the existing upper control arm.

Or you would really like to introduce a bushing to the party that would start squeaking and clunking.

The aftermarket upper control arms may also start causing clearance issues with your tires as they are typically meant to be used with a lift.

 

Most do not need them until you get up over 2 1/2”- 3”

 

How do you like the way it handles on the highway right now? Does it wander at higher speeds at all?

If so, an aftermarket UCA that allows a higher caster setting will solve that issue by tightening up the steering.

If you don't have that issue, leave it the way it is.

 

Upper CA's would have an impact to handling, and more specifically, increasing caster, which helps it track straighter and give a sense of tighter steering (mitigates that loose flighty feeling when driving at highway speeds).

No impact to ride quality, and in fact, technically speaking could have a very minor negative impact to ride quality as most use poly bushings, which aren't as forgiving or as good at absorbing road vibrations as stock rubber bushings. But of course the trade of here again is handling - the soft rubber bushings sometimes are a little too forgiving, and can lead to slopping handling overtime.

 

I take it when you said "camber", you meant castor, right? UCA's allow you get more adjustment range instead of being "maxed" out one way or another. As far as the ride quality the more the amount of caster, the more high speed stability you will have..... to a point. I do not believe they (UCA's) are going to smooth things out, at least ours didn't. The other 'plus' to aftermarket UCA's is the maintenance aspect.... they are greaseable.

 

Highway driving IS the situation that you would benefit from UCAs. 2.8 - 2.9 degrees of caster is too low on a lifted vehicle. Once you raise the center of gravity you want to want to increase caster past the factory spec. “Significant” is opinion based and some people or more sensitive and tuned in than others, but I would say yes, you will absolutely notice a difference being lifted going from stock arms with 2.8 degrees to something aftermarket with 4ish degrees.

 

265/70/17 no after market UCA is needed. 285/70/17 yes. After market UCA will give you more alignment options

 

Yes it will I’m using jba hi caster on a 2” lift and the on road performance is extremely notable
J

 

Can you elaborate on what you mean by notable

 

Spell check “noticeable improvement “
A more stable steering response when in movement feels sure footed

 

Ahhh got ya

 

A lot of different opinions, I have a 2.7 F & 1.7 R lift and 285/70/17 no UCA's replaced or diff drop. The rig tracks & articulates well on all kinds of speeds and off-road driving. The advantage of OEM UCA's they are maintenance free, as well the less you tamper with the geometry the better; taking limitations into consideration.

 

I was running about 4 -5 degrees of caster on my Tacoma. People need to realize once you start changing lift and geometry, the in-spec alignment numbers go out the window on a modded vehicle so don’t shoot for those. Best alignments I got on that truck were done by an old school alignment shop rather than the monkeys at Firestone that just hook it up to the machine and try and make the numbers match what the computer says for that model and year of vehicle.

 

Thank you, I seem to be following that path. The Eibach kit gives you 2.5 - 2.75 upfront. So far in 7000 miles it has been handling as good as a 4Runner will handle (it's not like my 2007 350Z). Seeing that it's working great, I'm leaving it for now.

 

I also have an Eibach Pro Truck Lift put on in 2019. I had SPC UCA's added when I went to 285/70R17 tires back in April of this year - 2021.
The steering feels tighter now.

Though not sure I can attribute that to the significantly heavier tires or the UCA's.