Roll center adjusters

[S14DB]

I thought these only worked on FWD cars. But now I see them for the rear on our cars. Would they help or a waste of money?

http://i10.ebayimg.com/04/i/000/7e/e8/357e_1.JPG
http://i9.ebayimg.com/02/i/000/7f/16/0a23_1.JPG


http://cgi.ebay.com/ebaymotors/240SX-Silvia-S14-S15-SR20DET-Rear-Roll-Center-Adjuster_W0QQcmdZViewItemQQcategoryZ42609QQihZ020Q QitemZ300060468497QQtcZphoto

[punxva]

im not sure if they would do too much, esp for $139, i'd say they arent worth it

[blu808]

I would not see any reason to get them out back. The front is worth it though if you are road racing.

Spl Parts.makes some nice ones.

So does alex at battle version with a DIY kit.

[McRussellPants]

Its debateble if those things actually change roll center. nobodys bought a set to actually see if it changes ball joint position or just spaces the LCA down

[projectRDM]

It spaces the Aarm down further, thereby changing the angle the ball joint sits in the upright. On a severely lowered car I can see it being a benefit, problem is it's a fixed adjustment unless you trim the spacer.
I think it's a great idea for the simple fact that you can now replace the rear ball joint without buying a new arm, whether you use the spacer or not is up to you.

[[email protected]]

It spaces the Aarm down further, thereby changing the angle the ball joint sits in the upright. On a severely lowered car I can see it being a benefit, problem is it's a fixed adjustment unless you trim the spacer.
I think it's a great idea for the simple fact that you can now replace the rear ball joint without buying a new arm, whether you use the spacer or not is up to you.

It does not actually change roll center because the pivot point is not moved. The lower arm sits at a different angle but that is just cosmetic, the line you need to look at is from pivot point to pivot point. The ball joint in this case is at a fixed length from the spindle, to actually change the roll center the ball joint shank has to be longer.

[cdlong]

So does alex at battle version with a DIY kit.

any more info on that, there's nothing on their site.

i need some new rear ball joint boots and i don't think i can justify buying the SPL ones for that repair.

[aznpoopy]

any more info on that, there's nothing on their site.

i need some new rear ball joint boots and i don't think i can justify buying the SPL ones for that repair.

i believe he is referring to these and as mentioned before, they are for the fronts
http://www.battleversion.com/240WeldKit.htm

[S14DB]

Prolly just get the Nismo A arms then.

http://projectnissan.com/shopping/pc/viewPrd.asp?idcategory=234&idproduct=3962

[projectRDM]

Kuah, it would appear that the shank on these units is indeed longer, at least a half inch.

Thoughts?

[cdlong]

i believe he is referring to these and as mentioned before, they are for the fronts
http://www.battleversion.com/240WeldKit.htm

those don't change roll center, just length (which i guess could technically change roll center but only a minute amount). those would only affect camber and caster.

Prolly just get the Nismo A arms then.

http://projectnissan.com/shopping/pc...idproduct=3962

are those any different than stock (other than bushings)? it doesn't say anything on the link. and they aren't even on the nismoUSA website.

Kuah, it would appear that the shank on these units is indeed longer, at least a half inch.

overall length is higher, but it's the position of the joint compared to the taper on the shank is what's important, and they don't look any different.

from the eBay auction "By extending the ball joint of the front knuckle, the position of the roll center is altered. "
i'm still a little weary. they aren't on HARDRACE's website either.

[SoSideways]

These look just like the Moonface ball joints.

And there was a loooong thread on them on ZT, and Wissass explained why they won't do anything to change roll center.

Not to mention the rear roll center isn't as important as the front roll center on a car. If I'm going to spend money to correct my car's roll center, it'll damn well be the front roll center.

[McRussellPants]

The Battle Version DIY kit isn't for roll center adjustment, its for flca length, which could technically change roll center but it will be too minute to matter.

Nismo LCAs don't change arm length or roll center, they're prolly just painted S15 control arms with hard rubber bushings.

SPL kit looks like it will space the LCA between an inch and an inch and a half.

Probably all you'll get out of the Hardrace/Moonface bushings is a minimal change in camber from changing the ball joint location in relation to the FLCA inner bushing.

[[email protected]]

Kuah, it would appear that the shank on these units is indeed longer, at least a half inch.

Thoughts?

You have to somewhat guess where the ball is located inside the cylindrical housing, but if it has a longer shank it will be obvious, the increased length will show above the housing. There is no "hidden" shank inside the housing because to place the ball low inside the housing and have part of the shank inside will severely limit the pivot angle of the ball joint.

MFR (Moonface) came up with these a long time ago, they have a newer version that has a longer shank, it is pretty obvious if you see them.

[McRussellPants]

Werd, I picked up a Doriten today with the MFR Pros in an advertisement.

the difference is noticeable and the balljoint shank is prolly an inch longer.

[S14DB]

I don't know about the Nismo's length. All I have been able to confirm is the stiffer bushings and re-angled ball joints which sit more level on a lowered car and the arm is boxed like the powerbrace. My drivers side joint is flat and I think on the way out.

[cdlong]

i decided to check with hardrace for some details. here you go for those that are interested.

my e-mail:
I have seen a few ball joints come up on eBay listed as Hardrace products but you don’t have them listed on your site. Can you verify if they are Hardrace products or not? And if so, can you tell me how much they extend the ball joint from the stock position?
Cory

response:
Cory
It is Hardrace product, and it is extended 1.5 cm from the stock position.
Regards
Roger Chang

[scottie]

I think it's a great idea for the simple fact that you can now replace the rear ball joint without buying a new arm, whether you use the spacer or not is up to you.

Are you serious?! I need to change my ball joint out on both rears and you're telling me i have to buy a whole new arm?! I know you can replace the joints that go from the rear lca to the rear subframe so i would assume you could replace the ball joint as well. Wouldnt make much sense for Nismo to make replacements for the (2) bushings if you cant replace the ball joint. Interesting.

[mrmephistopheles]

I have nothing useful to add to this thread other than my discovery of these at TAS'07

http://img64.imageshack.us/img64/7751/hurrrny5.jpg (http://imageshack.us)

[MadScientist]

Nismo LCA (Front & Rear) - Includes Nismo Bushings which are much stiffer than stock, Ball Joint angle is increased so less stress is applied when lowering the vehicle. Stamped and reinforced box section just like what you see on the Nismo Power Brace. Painted Nismo Silver.... same a Power Brace!!

Roll Center Adjusters - MoonFace Racing is the only place I trust with knowing any major detail... I have known about them for a long time and kept quiet... their products are awsome quality, but cost more. MF-R roll centers are easily twice as much as the HardRace or E-bay specials. MF-R offers 3 different models... Basic w/ Black Bottom; PRO w/ Silver Bottom; and PRO Racing w/ Gold Bottom.

This is what MF-R says about using this product!!!
Lower Arm equiped with Roll Center Adjuster corrects the level of the Arm to Normal position. Front will increase steering response, Rear will increase traction. By lower a vehicle the LCA moves upward placing the roll center off. Basically the LCA is not level so its not going to perform as well, it will actually be weaker. Roll Center Adjusters simply moves the LCA down to what would be stock position!
http://www.moonface-int.com/mfr/roll/rollmain/img/roll%5Bzu5%5D.gif

This all makes wonderfull since to me now... I understand everyones statements above as well! Take from this what you will... I will be getting a set of these so-called Roll Center Adjusters!!

Thank you
Drew

[upSLIDEdown]

Are you serious?! I need to change my ball joint out on both rears and you're telling me i have to buy a whole new arm?!

Correct. RLCA Ball joints cannot be replaced by themselves, you have to replace the entire arm.

[cdlong]

Roll Center Adjusters[/B] - MoonFace Racing is the only place I trust with knowing any major detail... I have known about them for a long time and kept quiet...

why would you do that to us?! if you know about all this cool shit, you gotta tell us.

on a side note, the angle of the arm itself really makes no difference, that's just their half-assed way of explaining that they moved the joint down. that's the reason some of us are weary, it's possible to change the angle of the arm without moving the joint down and that doesn't help at all.

Correct. RLCA Ball joints cannot be replaced by themselves, you have to replace the entire arm.

are you sure on that? nissan doesn't sell just the ball joint or boot but i thought you could press them out and replace them if you found some.

[MadScientist]

why would you do that to us?! if you know about all this cool shit, you gotta tell us.

on a side note, the angle of the arm itself really makes no difference, that's just their half-assed way of explaining that they moved the joint down. that's the reason some of us are weary, it's possible to change the angle of the arm without moving the joint down and that doesn't help at all.

Look at the image ^^^ what other way is their to lower the arm down without doing something drastic like cutting the arm in half and welding a sperical bearing to it, or raise the hight of the car??? The Chassis lowers and the outside of the arms will move upward... this applies stress on the bushing, and the arm is no longer obsorbing lateral force correctly... lateral force is being directed upward adding stress to the Upper Arms (rear) and Coilover (front). When the arm is level and sitting at its Designed possition the lateral force will be LATERAL and apply stress to the Subframe and Chassis!!

Why do I keep things like this under wraps??? Every resonse to this part alone has been negative... realize we are talking about a $150 e-bay special part... so $300 for front and rear, right! The MoonFace racing ones are $600-$800 depending on model.

Peace
Drew

[cdlong]

Look at the image ^^^ what other way is their to lower the arm down without doing something drastic like cutting the arm in half and welding a sperical bearing to it, or raise the hight of the car??? The Chassis lowers and the outside of the arms will move upward... this applies stress on the bushing, and the arm is no longer obsorbing lateral force correctly... lateral force is being directed upward adding stress to the Upper Arms (rear) and Coilover (front). When the arm is level and sitting at its Designed possition the lateral force will be LATERAL and apply stress to the Subframe and Chassis!!

Why do I keep things like this under wraps??? Every resonse to this part alone has been negative... realize we are talking about a $150 e-bay special part... so $300 for front and rear, right! The MoonFace racing ones are $600-$800 depending on model.

Peace
Drew

looking at the whole ball joint broken down into its parts-
threads, tapered shank, ball joint, spacer, press fit for LCA - does nothing for suspension geometry, only makes your car faster by making your wallet lighter. takes about 45 minutes to engineer.
threads, tapered shank, spacer, ball joint, press fit - good, changes the geometry and roll center. takes longer to engineer properly, may require higher strength materials and better ball joints (ask Kuah about bent shanks, the v3 tie rod ends have stronger steel because of the additional stress on the extended shanks).

it's the angle between the pivot points that's important. it's easy to fool people by just dropping the angle of the arm but that doesn't help at all.

i only brought up you selling them because as far as i know this is a new addition the the slew of crap on eBay, i might have bought a set of the moonface parts if i had known about them a year ago. buying crap on ebay with no information to back it up makes me nervous, i'd rather spend more on a reputable seller and parts.

[projectRDM]

are you sure on that? nissan doesn't sell just the ball joint or boot but i thought you could press them out and replace them if you found some.

From what I know, no one has found a rear replacement balljoint as of yet. There was some kid a while back who said the front ball joint works, as in it presses into the Aarm, but he never verified the taper or shank fitment so it was probably similar to using an S13 ball joint in an S14 spindle, it fits but doesn't fit correctly, and can bind or sheer off under load.
While the Ebay deals may not do what they say, it's nice for someone who's boxed their OE arm and added full aluminum bushings and just wants a replacement ball joint to bring it back to spec.

[cdlong]

From what I know, no one has found a rear replacement balljoint as of yet. There was some kid a while back who said the front ball joint works, as in it presses into the Aarm, but he never verified the taper or shank fitment so it was probably similar to using an S13 ball joint in an S14 spindle, it fits but doesn't fit correctly, and can bind or sheer off under load.
While the Ebay deals may not do what they say, it's nice for someone who's boxed their OE arm and added full aluminum bushings and just wants a replacement ball joint to bring it back to spec.

so it's parts avaliability, not the design of the arm?

[projectRDM]

Correct. You can press the OE ball joint like you would any other, there just isn't anything to go back in it. Except for the above pieces.

[Sonic Motor]

i know this is hella old thread.

But has anyone used the new Megan racing Roll Center Adjusters?
http://www.meganracing.com/products/product_detail.asp?prodid=783&catid=123

[Dousan_PG]

they dotn adj roll center
it was discussed in depth on ZT and FA before and even about

only advantage? need new rear balljoints
but u acn use Sentra ones and just bored it out a bit on the stock arm hole.

anyways waste of money.

[SoSideways]

It looks exactly like the ones sold on eBay.

[manka4343]

It does not actually change roll center because the pivot point is not moved. The lower arm sits at a different angle but that is just cosmetic, the line you need to look at is from pivot point to pivot point. The ball joint in this case is at a fixed length from the spindle, to actually change the roll center the ball joint shank has to be longer.

Any time you change the control arm angle, the roll center changes.. I wouldn't recommend randomly changing pivot points or angles without understanding what is happening with the suspension. This affects how the vehicle handles (under/oversteer, body roll, etc.) as well as camber and caster gain through the suspension travel.. If you want to learn how it is all tied together, get a decent suspension program (i use
http://www.performancetrends.com/SuspAnzr.htm ), take the time to take ACCURATE measurements, plug them in, and then make changes to angles/pivot points to see what happens...

[SoSideways]

Any time you change the control arm angle, the roll center changes.. I wouldn't recommend randomly changing pivot points or angles without understanding what is happening with the suspension. This affects how the vehicle handles (under/oversteer, body roll, etc.) as well as camber and caster gain through the suspension travel.. If you want to learn how it is all tied together, get a decent suspension program (i use
http://www.performancetrends.com/SuspAnzr.htm ), take the time to take ACCURATE measurements, plug them in, and then make changes to angles/pivot points to see what happens...

You just quoted a guy that makes suspension parts for the Z/S chassis world, and tried to tell him to learn about what he's been doing.

Just pointing that out for you.

[LongGrain]

You just quoted a guy that makes suspension parts for the Z/S chassis world, and tried to tell him to learn about what he's been doing.

Just pointing that out for you.

not just suspension parts, some of the BEST suspension parts on the market

[manka4343]

OK, I don't know who the guy is, I am new to Nissans... But, I have been around racing for a day or two, and know what changes to control arm angles do to roll center...

[SoSideways]

OK, I don't know who the guy is, I am new to Nissans... But, I have been around racing for a day or two, and know what changes to control arm angles do to roll center...

So do we.

But the point of this thread was basically whether or not the product in question will indeed move the control arm, resulting in a changed roll center.

Most people argued that it will not, and some believed it would.

I used to think it didn't move the arm, but now I think it does, upon closer inspection.

If you want to know who Kuah is, just go to www.splparts.com and look around. He runs the joint, and all the suspension arms he sells on there he either helped developed, or developed himself. If you have anymore questions, email/PM/contact him, not me.

[sideview_180sx]

everyone to talking about roll center on the LCA, has everyone forgotten about the angle of the tie rod and the bumpsteer associated with that increased angle. rather then get a roll center adjuster. How about lengthening the points on the knuckle to lower the position of the tie rod pick-up point and the LCA, better yet cut up the knuckle and make a spacer to space it out like how GP sports and 3up have done. Duh!

You figure the knuckle would be bigger so some people may whine about inned diatmeter clearance of wheels. In that instance, run 17s or bigger dammit.

[SoSideways]

everyone to talking about roll center on the LCA, has everyone forgotten about the angle of the tie rod and the bumpsteer associated with that increased angle. rather then get a roll center adjuster. How about lengthening the points on the knuckle to lower the position of the tie rod pick-up point and the LCA, better yet cut up the knuckle and make a spacer to space it out like how GP sports and 3up have done. Duh!

You figure the knuckle would be bigger so some people may whine about inned diatmeter clearance of wheels. In that instance, run 17s or bigger dammit.

Yeah, too bad the GP Sports knuckle is like friggin $1k USD!!

And only a handful of people will truly benefit from having those knuckles on their cars.

[[email protected]]

Any time you change the control arm angle, the roll center changes.. I wouldn't recommend randomly changing pivot points or angles without understanding what is happening with the suspension. This affects how the vehicle handles (under/oversteer, body roll, etc.) as well as camber and caster gain through the suspension travel.. If you want to learn how it is all tied together, get a decent suspension program (i use
http://www.performancetrends.com/SuspAnzr.htm ), take the time to take ACCURATE measurements, plug them in, and then make changes to angles/pivot points to see what happens...

The lengths and angles you input into any suspension program, is the length and angle defined by the imaginary line joining pivot point to pivot point. I can make an arm with all sorts of odd angles and curves, but in the end the only thing that is relevant to the suspension geometry is pivot point to pivot point. In this case, the ball joint makes the arm body appear to be at a different angle, but the pivot point is not actually moved, then nothing is really changed.

[manka4343]

I can't comment on that particular part, as I have not seen it in person.. I have, however, used diferent sized balljoints (taper or shank length) to change roll centers (mostly in the front, for circle track guys using a stock stub).. My presumption would be that those are either a longer shank or that the pivot point of the ball joint is moved with that spacer. If not, well sorry for stepping on my dick, and I'll shut up..

[Def]

You just quoted a guy that makes suspension parts for the Z/S chassis world, and tried to tell him to learn about what he's been doing.

Just pointing that out for you.

Manka is right though...

Imagine putting a 1 foot extension on the LCA to the balljoint. The actual change of the geometry of how the suspension moves has not changed at all vs. a direct arm going right to the balljoint.

You must move the pivot location to change the behavior of the suspension.

[cdlong]

So do we.

But the point of this thread was basically whether or not the product in question will indeed move the ball joint pivot point, resulting in a changed roll center.

Most people argued that it will not, and some believed it would.

fixed it for you.

i'm on the fence until the companies in question show some better pictures. if they do that, they have a chance of getting my buisness, if not, no way.

[timtiminy]

so wouldnt these essentially and theoretically do this...
http://i41.photobucket.com/albums/e273/timtiminy/rollcenter.jpg

[SoSideways]

so wouldnt these essentially and theoretically do this...
http://i41.photobucket.com/albums/e273/timtiminy/rollcenter.jpg

Yeah, but the argument is that those roll center adjusters will still place the pivot point at where the red line touches the spindle, and not where the red line touches the RLCA.

[Silverbullet]

I stress way more about the front, and i believe most people do as well.
Incase some ppl haven't figured this out, unlike the rear, our front suspension isn't double wish bone style. Rather, it is McPhearson and the RC is found in the following diagram:

http://us1.webpublications.com.au/static/images/articles/i1084/108488_8lo.jpg

We've been using Susprog3D in our class to play around with suspension geometry. Its a decent program for a free software.