Caster with stock UCA's

[Tdub06]

I've read around the site regarding caster but I can't seem to find a shop that has a clue how to adjust, including the dealer. I'm currently at about .5 but whenever I ask for 2 to 3 degrees positive they look dumbfounded.

I have stock UCA's- just icon coilovers, springs and 285's on stock wheels with spidertrax.

I've done all the body mount chops and hammering down of seams but I'm still rubbing on occasion.

Any advice? How is the caster adjusted with stock UCA's?

[ploar]

are you rubbing during normal driving, or when wheeling? Body lift might be your cheapest option, well atleast cheaper than UCA

[Chrisx]

I don't know what the caster should be but I've never had trouble getting mine aligned to "good enough" specs with the 3" lift. I find a shop to align by looking at employee vehicles and when I see a lifted truck pull in and ask who owns it. If it's a guy in the back I ask for him to do the work.

[Tdub06]

I get the occasional rub in normal driving, but it's enough to drive me nuts. No room for a body lift with a short garage but I still haven't given up on adjusting the caster.

Just need to know how it's done

[Tdub06]

Anyone know how to adjust caster with stock UCA's?

[UnionJack]

Originally Posted by Tdub06

Anyone know how to adjust caster with stock UCA's?

Not sure if this will help you much but here you go.

[shabaka]

if i'm reading that doc right...
caster is a value in relation to the camber
so every time you adjust the camber ...you effect the caster
but it looks like caster cannot be adjusted by it's self

correct me if I'm wrong

[UnionJack]

Originally Posted by shabaka

if i'm reading that doc right...
caster is a value in relation to the camber
so every time you adjust the camber ...you effect the caster
but it looks like caster cannot be adjusted by it's self

correct me if I'm wrong

I'll be honest I didn't read it just posted it trying to be helpful.

[harper7]

Originally Posted by Tdub06

Anyone know how to adjust caster with stock UCA's?

The aft cam bolts on the LCA's adjust caster and the front one adjusts camber. You need to adjust it on an alignment machine because adjusting one affects the other and camber should be near zero or a little negative. The more positive caster you have moves the wheel forward in the wheel well more.

[Tdub06]

Thanks all! Great stuff - just what I needed Much appreciated.

[4RunnerSeth]

Originally Posted by harper7

The aft cam bolts on the LCA's adjust caster and the front one adjusts camber. You need to adjust it on an alignment machine because adjusting one affects the other and camber should be near zero or a little negative. The more positive caster you have moves the wheel forward in the wheel well more.

This is misinformation, Both cam bolts adjust caster and camber in different ways. find something triangle shaped like your LCA and place it on a table. Imagine your wheel is attached to it. Then move the inside front and rear in and out and you will see how it moves. When you bring the front in it will pull the bottom of the wheel forward increasing caster, but will also move the bottom closer to the frame adding positive camber. now move the back in this will remove caster and also pull the wheel closer to the frame at the bottom increasing positive camber. With the opposite movement of each having the opposite effect. It's a delicate balance of both and not as simple as most would think. This is why a good alignment guy is hard to find. Most these 19 year old kids working at shops dont know what they are doing.

Originally Posted by Tdub06

Thanks all! Great stuff - just what I needed Much appreciated.

Unfortunately the most you will get with stock UCAs and 3"s of lift is about 1* of caster. Here is the kicker. UCAs will help your caster. Spec is 2.4*, but will make your rubbing issues worse. Adding caster at the bottom will pull your wheel away from the rear of the wheel well and adding caster at the top will push it back. The stock adjustments are not just about getting you more caster. You can get more caster with a 3" lift. The issue is that you cant necessarily get the caster while keeping the camber good as the adjustments effect both caster and camber.

[harper7]

Originally Posted by 4RunnerSeth

This is misinformation, Both cam bolts adjust caster and camber in different ways. find something triangle shaped like your LCA and place it on a table. Imagine your wheel is attached to it. Then move the inside front and rear in and out and you will see how it moves. When you bring the front in it will pull the bottom of the wheel forward increasing caster, but will also move the bottom closer to the frame adding positive camber. now move the back in this will remove caster and also pull the wheel closer to the frame at the bottom increasing positive camber. With the opposite movement of each having the opposite effect. It's a delicate balance of both and not as simple as most would think. This is why a good alignment guy is hard to find. Most these 19 year old kids working at shops dont know what they are doing.



Unfortunately the most you will get with stock UCAs and 3"s of lift is about 1* of caster. Here is the kicker. UCAs will help your caster. Spec is 2.4*, but will make your rubbing issues worse. Adding caster at the bottom will pull your wheel away from the rear of the wheel well and adding caster at the top will push it back. The stock adjustments are not just about getting you more caster. You can get more caster with a 3" lift. The issue is that you cant necessarily get the caster while keeping the camber good as the adjustments effect both caster and camber.

Misinformation??
I said in my post that one affects the other.

The place where I go to get my alignments done is a small little shop with an old guy that does alignments and has been doing alignments for 30 years. First 2 times I had my truck aligned he lets you watch and bs with him right there while your trucks on the rack and he shows you what he's doing.

I had my caster set to a little less then 4 the second time and wanted to take it even higher and he put it on the rack and set it up and said, here's the wrenches . You put it wherever you want it as you watched me twice you should know how to do it by now.

First ,you loosen the 2 cam bolts on the LCA and back off the nut one turn on the tie rod.
Adjust the rear cam as you watching the readout to get the highest caster you can. Then you adjust the front cam to bring the camber down to zero. That will bring your caster readings down a little so you adjust your rear one to get max caster again and you repeat the front back til you get the caster you want with camber near zero.

I have LR UCA's and could get about 5.6 degrees of caster which is about max. Some other guy Tightening them up changes it a, little and then you adjust the tie rods to get the toe and tighten them up. Best part was, Stan said no charge ,you did all the work!Anybody around the DFW ,this place is Golden Triangle Collision center in N. Ft. Worth. Best little mom and pop shop around.

So lets hear how you do an alignment since your the expert ,so I can teach Stan!

Not sure how you figure more caster will make it rub more. I was rubbing on the body mount and after moving it forward a little more with more caster there was no more rubbing. Plenty of room in the front on my 5th Gen 4Runner and they ride much better with more caster.
Here's the print out of my alignment and it's been almost 2 years.Tires have worn perfect and runs straight and true to this day.

[4RunnerSeth]

Originally Posted by harper7

Misinformation??
I said in my post that one affects the other.

The place where I go to get my alignments done is a small little shop with an old guy that does alignments and has been doing alignments for 30 years. First 2 times I had my truck aligned he lets you watch and bs with him right there while your trucks on the rack and he shows you what he's doing.

I had my caster set to a little less then 4 the second time and wanted to take it even higher and he put it on the rack and set it up and said, here's the wrenches . You put it wherever you want it as you watched me twice you should know how to do it by now.

First ,you loosen the 2 cam bolts on the LCA and back off the nut one turn on the tie rod.
Adjust the rear cam as you watching the readout to get the highest caster you can. Then you adjust the front cam to bring the camber down to zero. That will bring your caster readings down a little so you adjust your rear one to get max caster again and you repeat the front back til you get the caster you want with camber near zero.

I have LR UCA's and could get about 5.6 degrees of caster which is about max. Some other guy Tightening them up changes it a, little and then you adjust the tie rods to get the toe and tighten them up. Best part was, Stan said no charge ,you did all the work!Anybody around the DFW ,this place is Golden Triangle Collision center in N. Ft. Worth. Best little mom and pop shop around.

So lets hear how you do an alignment since your the expert ,so I can teach Stan!

Not sure how you figure more caster will make it rub more. I was rubbing on the body mount and after moving it forward a little more with more caster there was no more rubbing. Plenty of room in the front on my 5th Gen 4Runner and they ride much better with more caster.
Here's the print out of my alignment and it's been almost 2 years.Tires have worn perfect and runs straight and true to this day.

It depends on where you add caster on whether it will make the rubbing worse or better. at the bottom will pull the tire further away from the body mount. caster added at the top will move the wheel further back in the wheel well. I'm not trying to start a pissing match with you. was just stating that its not as simple as turn one for caster and one for camber. I have helped a lot of people over on TW to get the caster they need for stability with LRs while not causing more rubbing issues. Sounds like the 5th gen has more room in the wheel well. I know tacomas and FJs if you got that much caster with the LRs you would have a lot of rubbing. I know im new here but I have done a LOT of suspension work on tacomas and FJs and have a good reputation as well as being an engineer.

[UnionJack]

All good information keep it coming always looking to learn

[harper7]

Originally Posted by 4RunnerSeth

It depends on where you add caster on whether it will make the rubbing worse or better. at the bottom will pull the tire further away from the body mount. caster added at the top will move the wheel further back in the wheel well. I'm not trying to start a pissing match with you. was just stating that its not as simple as turn one for caster and one for camber. I have helped a lot of people over on TW to get the caster they need for stability with LRs while not causing more rubbing issues. Sounds like the 5th gen has more room in the wheel well. I know tacomas and FJs if you got that much caster with the LRs you would have a lot of rubbing. I know im new here but I have done a LOT of suspension work on tacomas and FJs and have a good reputation as well as being an engineer.

Caster moves the wheel forward(more positive) or aft in the wheel well.It's the angle of the steering pivot. You can't add some at the top or bottom. Your thinking of camber. http://www.familycar.com/Alignment.htm

[4RunnerSeth]

Originally Posted by harper7

Caster moves the wheel forward(more positive) or aft in the wheel well.It's the angle of the steering pivot. You can't add some at the top or bottom. Your thinking of camber. http://www.familycar.com/Alignment.htm

caster is the angle of the steering plane. To tilt that plane up...IE positive caster. you can either move the bottom forward and hold the top steady or move the top back and hold the bottom steady to get the same resulting change in angle. no matter which you do you will also result in moving the entire wheel forward or back because the wheel is mounted in the middle of the lever that is the spindle. which direction it moves depends on whether you move the bottom forward or the top back. If you move the top back to add caster or increase the steering plane angle then you are also moving the wheel back in the wheel well resulting in it being closer to the body mount/rear wheel well. grab a pencil and stand it straight up. then move the top back and see what angle you get. return it to straight up and then move the bottom forward the same amount and the resulting angle will be the same except the center of the pencil moved in a different direction to get the same resulting angle.