Body Mount Rub Question

[JSparky]

I just finished installing some new suspension components and have a question for those more experienced. I've got Fox coil overs up front set at approx 2.5 inches of lift with Total Chaos uca's. Rear is on 2'' Radflo springs. Just had 285/70/17 Cooper ST Maxx mounted on Konig Countersteer Type X (-10mm offset), no wheel spacers. As I approach full wheel-lock the tires rub on the body mount. I was under the impression that at 2.5 inches of lift and no spacers I should be fine with 285's.. with the body mount chop reserved for larger tire sizes and/or wheel spacers?

I talked to the alignment shop and the tech said he installed a "caster kit" and that he couldn't push the tires any further forward away form the body mount without the alignment going out of spec. Does this sound legitimate? Or should I have them take a second look at it? I'm used to solid axle jeeps so please excuse my ignorance, still learning the IFS. It seemed surprising to me that they could only get 2.8 degrees on the left side, I'd have thought with the UCAs there should be more than enough room.. unless that is what's pushing the tire back. Either way, if someone wouldn't mine looking over these numbers I'd be grateful. I'm trying to figure out if there's something not right here or if it's just how it is.

Lastly, I could crank the coilovers up more, but I really like the stance. That and I plan on adding a winch/bumper combo which is going to load it back down again. I'd prefer not to body mount chop.. any other recommendation? Thanks everyone.

 

[Jeremy556]

The negative offset wheels produce the same result as spacers, making rubbing at the body mount worse.

Your alignment tech doesn't know what he's doing and is lying (caster kit). Everything he did on the eccentric adjusters made your alignment worse than it was to start with. You had 3.5 caster on both sides when he started, and 2.8 and 3.2 at the end.

With TC UCAs, unless something is badly bent, you can get 4 degrees with ease. I run 5.5 with a little negative camber, but still well within spec.

All that said, with -10 offset on (presumably) 8" wheels, you'll probably still have to do the BMC to avoid rubbing at full lock/stuff.

 

[wfo9]

I have not figured out why some people have rub issues on the body mount while others mainly have issues on the front fender with similar setups. My guess it is related to the alignment and how caster was set, but it could be differences in tires/rims. Aftermarket UCAs should move the top mount position back to bias in more overall caster.

Take a couple of measurements for us and I can compare them to mine.

See Attachment for ABCD measurements to gather.

I got the following on my passenger side (drivers sits a bit lower)
A 32"
B 3.6"
C 2.6"
D 6.9"

I don't rub in any situation and have my body mounts intact. I did push my front fender liners way forward.

 

[Intruder]

The negative offset wheels produce the same result as spacers, making rubbing at the body mount worse.

Your alignment tech doesn't know what he's doing and is lying (caster kit). Everything he did on the eccentric adjusters made your alignment worse than it was to start with. You had 3.5 caster on both sides when he started, and 2.8 and 3.2 at the end.

With TC UCAs, unless something is badly bent, you can get 4 degrees with ease. I run 5.5 with a little negative camber, but still well within spec.

All that said, with -10 offset on (presumably) 8" wheels, you'll probably still have to do the BMC to avoid rubbing at full lock/stuff.

Yup, this is my experience with TC UCAs as well. Find another alignment tech. I had one who put my caster back into spec to get the other settings into spec. I told him that I didn't care about being in spec as long as the caster was at least 4 degrees and it drove straight. He brought it back in and that's exactly what I got. Just need to find an alignment tech who isn't hung up on everything being in spec.

 

[wfo9]

Oh yea, -10 offset. That would push your wheel lip out 10mm compared to what I have. 8" rim with 0 offset.

More caster might solve it. Still would be interesting to see your measurements for reference.

 

[Jeremy556]

For alignment, there are eccentric adjusters at the front and rear of the lower control arms (4). These adjuster move the mounting points of the LCA, and hence the lower ball joint, which is what changes caster and camber.

95% of the time, alignment techs won't touch any of these bolts, and just adjust the tie rods for toe, which is the major alignment wear component.

What they will need to do (and most won't listen) is to push the lower ball joint as far forward as possible by pushing the rear cams all the way out and the front cams all the way in. This will max out caster, which is where they should start from. From there, they'll have to re-adjust front AND rear to pull camber back into spec without giving up too much caster.

It is tedious and time consuming, so if they are doing alignments for $40 or $80 or something flat rate, they will be losing money. If at all possible, find a shop that specializes in modified Toyotas.

 

[wfo9]

For alignment, there are eccentric adjusters at the front and rear of the lower control arms (4). These adjuster move the mounting points of the LCA, and hence the lower ball joint, which is what changes caster and camber.

95% of the time, alignment techs won't touch any of these bolts, and just adjust the tie rods for toe, which is the major alignment wear component.

What they will need to do (and most won't listen) is to push the lower ball joint as far forward as possible by pushing the rear cams all the way out and the front cams all the way in. This will max out caster, which is where they should start from. From there, they'll have to re-adjust front AND rear to pull camber back into spec without giving up too much caster.

It is tedious and time consuming, so if they are doing alignments for $40 or $80 or something flat rate, they will be losing money. If at all possible, find a shop that specializes in modified Toyotas.

Right, and the after market UCA, should move the upper ball joint back a little compared to stock resulting in more caster. Some are even adjustable up top and that will really throw most techs for a loop (to the point where it is almost not worth having them adjustable)

 

[Jeremy556]

Right, and the after market UCA, should move the upper ball joint back a little compared to stock resulting in more caster. Some are even adjustable up top and that will really throw most techs for a loop (to the point where it is almost not worth having them adjustable)

Exactly. In fact, with the LR/SPC UCAs with the sliding ball joint, it is much easier to adjust by moving the lower ball joint forward, then correcting almost any amount of camber by sliding the upper ball joint. Odds of finding a tech that understands these things are incredibly low.

 

[1engineer]

The biggest thing to understand is not all 4Runners are created equal. This is why there are suspension adjustments to begin with! Manufacturing tolerances, wear, stack up tolerances etc can and will cause differences. That's why there is a range on alignment settings. Now you throw a new different spec wheel, a bigger tire (tires are not the same size even though they are the same spec) and all of a sudden you are rubbing. That's why my Tire Fitment Guide is vague. A 285 might fit with no mods on one unlifted truck and rub the body mount on a lifted truck. [MENTION=96425]JSparky[/MENTION] I don't know who told you it would fit with no rubbing. They should have told you it MIGHT fit without rubbing lol. Listen to [MENTION=66300]Intruder[/MENTION] and [MENTION=78273]Jeremy556[/MENTION] as they know their stuff.

 

[JSparky]

Awesome.. thanks for the input everyone this was exactly the kind of response I was hoping for. I knew the negative offset on the wheels could create an issue, but I figured it'd be minor at best.

Jeremy556: thanks for the comment, it didn't sound right to me either. I was under the impression the eccentric bolts adjusted just camber so I'll have to study this more.. I know what caster is I just wasn't sure how it was adjusted on ifs (threw me off even more when I saw some uca's are adjustable).. little bit different than adjusting radius arms on a jeep. I REALLY appreciate you detailing the alignment process, this helps me alot.

wfo9: sounds great, I'll take some measurements tomorrow.

Intruder: good advice, I paid for "unlimited alignment" for life of the tire so it'll be interesting to see how this plays out.

1engineer: good thing to keep in mind. I misspoke if I said I it wouldn't-ever.. what I meant was that it likely won't, and if it did rub it'd but on some minor piece of plastic that could be trimmed away, not the body mount.

I'm going to go back to the shop tomorrow and see what I can do, hopefully they'll follow through with everyones recommendations. Thanks again guys, I owe you all a bite or a beer if we ever get the chance to meet up. I'll report back tomorrow for those interested.

 

[BlackWorksInc]

2.8* is stock "Middle Ground" or roughly where the alignment machine wants you to put the measurement between the two extremes. The tech most likely aligned it according to factory specifications (which he isn't exactly wrong to do.) But you need to impose on them that what you need is anything north of 3.5* Caster with reasonable Camber (some people like a hair on the negative side.) This should be doable with the UCAs you have installed.

I easily got almost 4* of Caster with almost 0* Camber with my LR UCAs (I got a bit lazy and just set it around 3.8* because the Camber was a bit out of what I wanted and I didn't feel like messing with the upper ball joint)

On a side note, is negative camber better for off-roading on a IFS set-up? I would think a hair of postive would be better as it would flatten out as the wheel compresses?
[MENTION=66316]1engineer[/MENTION] [MENTION=78273]Jeremy556[/MENTION] Opinions, thoughts, criticisms on my decidedly haven't been bothered to care about Camber attitude?

 

[JSparky]

2.8* is stock "Middle Ground" or roughly where the alignment machine wants you to put the measurement between the two extremes. The tech most likely aligned it according to factory specifications (which he isn't exactly wrong to do.) But you need to impose on them that what you need is anything north of 3.5* Caster with reasonable Camber (some people like a hair on the negative side.) This should be doable with the UCAs you have installed.

I easily got almost 4* of Caster with almost 0* Camber with my LR UCAs (I got a bit lazy and just set it around 3.8* because the Camber was a bit out of what I wanted and I didn't feel like messing with the upper ball joint)

On a side note, is negative camber better for off-roading on a IFS set-up? I would think a hair of postive would be better as it would flatten out as the wheel compresses?
[MENTION=66316]1engineer[/MENTION] [MENTION=78273]Jeremy556[/MENTION] Opinions, thoughts, criticisms on my decidedly haven't been bothered to care about Camber attitude?

Noted. If caster is adjusted via the cam bolts on the lower control arm then it makes sense to request more caster, that'll help pull the tire away from the body mount.. hopefully it's enough to clear it completely.

 

[txbonds]

Tagging along to see outcome.

 

[wfo9]

Another benefit of having more positive caster is the much improved hwy manners. It makes the truck want to go straight at speed vs being twitchy and light. If you have experience on two wheels... it is the same as slackening the head angle. Try riding a steep head angle bike downhill at speed and you will quickly feel how unstable it is.

As far as camber goes, I can't imagine it making much of a difference for most offload situations (aired down....). I would want to keep mine as close to 0 as possible and would want slight negative over positive for on road handling and wear.

 

[Jeremy556]

On a side note, is negative camber better for off-roading on a IFS set-up? I would think a hair of postive would be better as it would flatten out as the wheel compresses?
[MENTION=66316]1engineer[/MENTION] [MENTION=78273]Jeremy556[/MENTION] Opinions, thoughts, criticisms on my decidedly haven't been bothered to care about Camber attitude?

Camber shouldn't change much through travel, with a double wishbone design the track width changes more than camber, unlike a strut.

This image is of equal length arms, which is different from ours, but demonstrates the principal.

 

[470SNC]

with that much caster forward, how are you not rubbing on stock bumper in front or do you guys all have aftermarket bumpers? I have about 2.8 degrees of caster and my 285 is pretty close to the bumper corner.

 

[Jeremy556]

with that much caster forward, how are you not rubbing on stock bumper in front or do you guys all have aftermarket bumpers? I have about 2.8 degrees of caster and my 285 is pretty close to the bumper corner.

You can make a lot of room by moving the fender liner forward and making new mounting holes. I still had to cut a couple of spots and use a heat gun to reshape.

 

[470SNC]

I basically trimmed the fender liner all the way up, and had to cut the inside lip of the bumper and still rubs a tiny bit at full lock fully stuffed, maybe the 4runners have a little more clearance than my GX

 

[JSparky]

Update to the original post. Went back to the same shop to give them a chance to make it right. Caster is now up in the mid 4-degree range and, like you all said, has given me substantially more clearance for the body mount. On level ground there is no contact with the body mount at full wheel-lock, but there IS contact with the front fender liner. I performed harper7's liner mod and it took care of the problem. Under full stuff, full wheel lock there is still minor contact with the front fender liner, nothing I'm concerned about. However under suspension compression at full-lock there is still contact with the body mount. I haven't determined yet how much compression it takes to make contact as I only did a full-stuff test. I plan on doing some urban wheeling tonight to see how far I can push it till it rubs the mount. More than likely I'll be modding the body mount in some way as I really don't want contact there. Thanks again for everyones input, I learned a lot from this thread.

Here are the new alignment specs. I'm not sure why they set the toe out, seems like toe would be completely independent of the other movements? Also are two shots at full wheel-lock, before doing the fender liner mod.

 

[JSparky]

Another benefit of having more positive caster is the much improved hwy manners. It makes the truck want to go straight at speed vs being twitchy and light. If you have experience on two wheels... it is the same as slackening the head angle. Try riding a steep head angle bike downhill at speed and you will quickly feel how unstable it is.

As far as camber goes, I can't imagine it making much of a difference for most offload situations (aired down....). I would want to keep mine as close to 0 as possible and would want slight negative over positive for on road handling and wear.

Right. On my jeep (3-inch springs and 35s) I ran between 5-6 degrees of caster and slightly toe-out.. that solved death wobble issues until I was able to upgrade to long-arms, dropped track bar, and drag link flip to match the geometries.. after that I dropped caster back to 3.5-degrees to improve the driveline angle at the pinion. It was a dream on the freeway, could cruise with one finger on the wheel. To this day I don't understand how people can feel safe driving at high speeds in lifted jeeps without the proper steering mods.