Uca’s

Looking at getting a 6112/5100 lift in the future. I plan on keeping the factory rake for towing my boat or loading gear. Would I need to replace the uca’s if I do a 2 to a 2 1/2 lift in the front?

 

good question.
many folks run factory uca’s here with suspension lifts and report it’s OK.
perhaps excessive wheel width and offset, and/or large tires could warrant uca’s.

nice work purchasing a 2024 OR

 

Caster granted by UCA’s actually push the wheel further back into the body mount and firewall. So high caster UCA’s would increase the chance of rubbing in these areas (regardless of tire/ wheel sizes)



OP the only reason you’d need UCA’s after lifting is to regain the caster lifting costed you. So the short answer would be no, you don’t need them.

If you cannot achieve the caster settings you want (usually 3 degrees at least) then you may benefit from Dobinsons, Apache, or any other UCA that has some caster built into them. Although at 2” of lift, you should still be able to get some decent caster.

Btw the symptoms from not enough caster is usually highway wandering. 3-4 degrees is the sweetspot for these rigs imo.

For reference I have a 3.5” lift and Apache UCA’s. Able to achieve around 4 degrees without sacrificing camber or toe. Tracks nice and straight even at high speeds. No wandering whatsoever.

 

Probably not.

It seems like it becomes necessary somewhere between 2.5 - 3" of lift. You "should" be able to get alignment in spec at 2 - 2.5 with factory UCA's.

 

I stand by my statements.
I agree and disagree a little at the same time.
Didn’t say buddy needed them, I asked what else he’s running.
My last alignment was mint, slightly higher caster than before after lifting another .75”, over 3” total.

 

Some after market spring/shock packages may rub on control arm due to size increase.

 

Sorry DJ but that's incorrect. Why high caster UCA's reduce clearance at the firewall/ body mount and your alignment bolts do not is simple:

Alignments on the Prado platform are completed with the eccentric bolts in the lower control arm. Caster granted by these push the wheel forward. While caster granted by the upper control arm push the wheel backward (into the firewall and body mount)

The image you attached will actually help explain this:


This is why many long travel kit's use high caster LCA's. Effectively moving the wheel further forward, away from the firewall. This has some other benefits as well of course.



Sorry for the tangent just wanted to make sure we didn't lead OP to believe he needed UCA's for wheel/ tire clearance. That would be incorrect.

Other considerations for UCA's other than a proper alignment would be
-Some coilovers have a wider diameter and could contact the OEM UCA
-Some aftermarket UCA's do have a wheel offset/ backspacing requirement. Both SPC and JBA come to mind, since the ball joint cups are larger they may contact the tire if you run positive offset wheels.

All this is a lot for someone who doesn't really understand IFS which is why I usually tell people to just run a <2" lift and use the OEM UCA's. Keeping it simple and using OE parts can save some headache... and money if you're having a shop do the install for you.

 

no

 

you dont have to swap the UCAs, Ive had the eibach on for 2 years now and no issues at all. You do have to swap them for 3+ inches

 

my last alignment my wheel moved forward, from a combination of lca and UCA lol
Thanks, as always, for the knowledge I gained

 

No. Wheel offset is more important to get your tires to fit without hitting the frame turning. If you have TRD wheels, I don't think you should have to replace anything. I did upgrade because I didn't know what to expect changing things and my first 5th gen, but from what I see now, I did about 4" , changed UCAs for 285s and if I had just used TRD wheels, I wouldn't have had to replace any of that. Now I'm going back to TRD wheels a some point after all that. I do like being able to grease my ball joints. I used Freedom Off Road UCAs and I will probably use their LCAs eventually. Great service and customer service and all you need. All a 4runner really needs is good tires and driver. If you can't get there, you probably aren't supposed to be there.