Light Racing uca

Hi All:

I asked in the suspension thread but not getting any answers.

I installed the light racing upper control arms with setting D. Assuming I would add more lift later. Well its been over a year and its not going to happen.
Right now I have 5100 set at .85. 275/70R17 tires.

Alignment is Caster 2.7 toe 0 camber 0

Thing is, I feel some bump steer and the truck wanders. It has been like that since installing the uppers.

Question is, am I screwing up things by having the uppers set on position D? The alignment specs are good. But would I get better handling if the uppers were set closer to factory?
Or is 2.7 caster at D the same as 2.7 caster at say A using these uppers?

 

Others can chime in but 2.7 caster seems like a lot for that lift height. 2.7 would be more suitable at 3"s of lift.

https://www.tacomaworld.com/threads...driving-report-with-light-racing-ucas.158795/

 

My understanding is that the caster set at 2.7 improves handling, but more importantly centers the tire in the wheel well. Right now the tire just clears front and back of the wheel well during turns.
Maybe I am all wrong?

And I am wondering about using the D setting. I question if the suspension is "out of whack" with the D setting, even if the alignment numbers are in.

The thread you linked to was the one I originally posted this question in.

 

Caster is relevant to the lift height. It's not just "the more caster equals better handling". I have 2.5" of lift with the same LR UCAs set at 1.8 caster with no problems. Lot of guys put as much caster as they can because it allows the UCAs to clear the larger tires they have.

 

So I do have my info wrong.
Appears I should decrease my caster some. Easy enough.
I imagine I should put the uppers in a more factory setting too.

Caster does change the position of the tire in the wheel well correct? Anyone have any idea how far the wheel will move back is I go from 2.7 to say 1.5? Its math, I suck at math.

 

It does move it a bit. I would assume nothing dramatic enough to rub those 275 tires. Put the UCA with logo facing out. I would try it at 1.8 or so caster imo and give that a try. There's no real dramatic right or wrong with that lift size. It's more less how the driver likes the feel.

 

That's not bump steer....

 

Out of curiosity, Why would you set the caster at 1.8 with the LR UCA's? I'm about to get mine installed. Right now my caster is 2.3 with stock UCA's. I love the ride. Preferably I'd like to keep it that way.

 

Pretty simple: moar caster = "heavier" steering feel, generally better tracking in a straight line all other things being equal

 

Interesting. So, more caster isn't necessarily a good thing is what I'm understanding from this as well as the thread that was mentioned in this one

 

I have adjustable coilovers. I had the UCAs at 2.7 when I had the lift set at 3"s. After riding around at 3"s for a while I found the ride too stiff/harsh so I lowered the coilovers to provide around 2.25"s (I believe it was) for a softer ride and at the time I also lowered the caster. One The of the benefits of having multiple adjustable parts is you can find settings you like and change whenever you want.

 

With the caster at 2.7, did you like the ride? Aside from the stiffness that I'm guessing was caused by the lift

 

Ya it rode fine to me. The roughness was the coilovers. Tracked better at 2.7. More caster reduces its tendency to wander but harder to turn. Its all personal preference. Nothing dramatic enough to make me hate/love one over the other.

 

What is it when the front wheels turn (follow) in the direction of a rut on the road?

 

Poor alignment/ tramlining/improper tire pressure. If the ruts are big enough all tires/susp geometries will do it.

Bump steer is a change in toe as the suspension cycles due to the suspension arc and tie rod arc not being equal. In stock form there's little to negligible difference in the arcs. But once you lift/lower your changing suspension geometry which can cause the arcs to not be equal, in which case when the suspension cycles toe changes.

 

Which is what is confusing me. From memory, my truck does not track as well as it did at factory settings.
It has been a while since I made all the changes. I should get the changes done and then report back.

Nice explanation. Thanks. So its possible that I may have screwed up the geometry of the front suspension by setting the uppers at position D, with 2.7 camber but having little lift.
In the next few weeks I am going to set the uppers at a close to stock position and set my caster close to factory specs. See how much of a change I get.

 

What are the factory specs?

 

What are your current alignment specs?

 

im at 3.0 caster and perfect for me !!

 

Currently I am at caster 2.7, 0, 0 With only a slight front end lift.

I said camber in previous post. Should have been caster.