This is the roll center, suspension pickup, and steering angle modification thread.

[GripTerror]

I hate cars too... (yet love them)....... i hate cars LOL... I know EXACTLY what you mean..... its like i spend money on one part then... end up spending on same but better part again and lose money on the first purchase

Well I am quite excited to see/hear pictures/videos/whatever of what you get tomorrow I'm quite anxious

[Csomme]

So I have my car at this height:



And I read this entire thread on Monday. On Tuesday evening I went and drifted the car at a local practice event. Holy Shit. Needless to say, I will be raising my car up untill I can sink some serious cash into a decent suspension set-up.

I would hit full lock and have to litterally yank the wheel with both hand the other way to get it to turn. Ahh. too much shit to talk about. But I now see that I would rather drift better on track than look better on the street.

[ManoNegra]

Please keep this thread on topic.
Looking forward to the review Jimmi.

[mikerbike]

Originally Posted by GripTerror

Look what I also just found:



Improve craft CRUISE

Isn't that to convert an AE86 to IRS? Uses S13 drive parts if it's what I've seen before.

Edit: then I clicked some links. oops

[mmdb]

Got my Driftwork knuckles in today. I was very pleased with the customer support. They delayed my shipment until this week. After I followed up with an email asking for status, they apologized for the delay and sent the knuckles from England to my home with 2 day shipping! WOW!

As for build quality these things were meant to last. The parts look and feel like top quality. The parts come powder coated orange (this caused a very, very minor problem as I fitted bolts through the holes. No biggie.) Install was seamless. I didn't have to rig anything to fit. These guys did their homework!

As for roll center, duh, you can see how these compare to stock and the GP sports. Notice the shock mounting location between the Driftwork vs the GP Sports. The GP sports knuckle being higher, caused me to lower my shock collar to the furthest lowest position. This might've caused sudden understeering issues as the shocks might have bottomed out.

In contrast to the Driftworks knuckle, I needed to fully heighten my shock perch because my car was riding SO LOW (this will most likely not be an issue with a shock with an adjustable perch). It concerns me a bit because I'm afraid of the lack of droop travel. Only track time will tell.

As for performance reviews, I'll have to install the rear knuckles to leave a fair review. As for now I'll let the pictures do the talking. Enjoy!









Stock weight



Lined up by the LCA mounting point.



GP Sports vs Driftworks (notice the shock mounting point)



Steering arm length...







Rear Knuckles. NOtice the hub mounting holes location in relation to each other.

[longfellow]

Damn those are awesome. I might order a set one day.

[PoorMans180SX]

Nice! Those look great.

Do you guys think it's possible to use thinner gauge steel to balance the weight issue out? Those are SUPER beefy.

[ManoNegra]

Your pictures do a lot better job of showing the construction quality of the knuckles
than the ones on their site
they do look very robust indeed
and it's also good to know that the weight difference isn't much

do you have a picture of the front caliper fitment?
maybe it's the angle of the pics but the caliper mounting points
of the front knuckles look different to me compared to the oem

does the hub shaft look new of did they cut off the one from an oem knuckle
and welded it on theirs?

is the balljoint taper correct?
it would have been cool if they could have made a larger hole and then
provide tapered inserts (like rear Z32 arms) that would allow you to use either s14 or s13 ball joint LCAs.

Did they move down the z32 e-brake bolting holes? (I presume)
That's a good idea
btw, if the bushing diameters are OEM size
you can press them out and install spherical bearings in them
the holes need to be precise though because, as we found out the hard way,
a few thousand off on the bushing diameter is all it takes between a press fit and a mangled bearing

looking forward to the shakedown review

[mmdb]

Originally Posted by ManoNegra

do you have a picture of the front caliper fitment?
maybe it's the angle of the pics but the caliper mounting points
of the front knuckles look different to me compared to the oem

It looks to be that way as well. I'll take some better pictures when I get home.

Originally Posted by ManoNegra

does the hub shaft look new of did they cut off the one from an oem knuckle
and welded it on theirs?

They did weld the hub shaft on. I'm not sure if it's directly from an OEM knuckle. Is there a way I can tell? I'll stick them side to side and see if I can notice anything.

Originally Posted by ManoNegra

is the balljoint taper correct?
it would have been cool if they could have made a larger hole and then
provide tapered inserts (like rear Z32 arms) that would allow you to use either s14 or s13 ball joint LCAs.

I was in a bit of a run to install them, but I'll take another look as I install the other side today. They went in without any issues.

Originally Posted by ManoNegra

Did they move down the z32 e-brake bolting holes? (I presume)
That's a good idea
btw, if the bushing diameters are OEM size
you can press them out and install spherical bearings in them
the holes need to be precise though because, as we found out the hard way,
a few thousand off on the bushing diameter is all it takes between a press fit and a mangled bearing

looking forward to the shakedown review

I won't have a chance to install the rear knuckles yet and it might be a while till I do. According to Driftworks the z32 ebrake should be bolt on with the exeception that the left and the right are swapped. I'll know when I attempt to do the install.

[ManoNegra]

do you have a picture of the front caliper fitment?
maybe it's the angle of the pics but the caliper mounting points
of the front knuckles look different to me compared to the oem

It looks to be that way as well. I'll take some better pictures when I get home.

Seems to me that the caliper location in relation to the shaft needs to be precise to ensure proper rotor coverage

does the hub shaft look new of did they cut off the one from an oem knuckle
and welded it on theirs?

They did weld the hub shaft on. I'm not sure if it's directly from an OEM knuckle. Is there a way I can tell? I'll stick them side to side and see if I can notice anything.

I don't think it matters much as long as it's there securely
it would make sense to use an existing shaft as oppose to machining them new
wonder how perpendicular to the knuckle it is?

is the balljoint taper correct?
it would have been cool if they could have made a larger hole and then
provide tapered inserts (like rear Z32 arms) that would allow you to use either s14 or s13 ball joint LCAs.

I was in a bit of a run to install them, but I'll take another look as I install the other side today. They went in without any issues.

Probably more to do with the powder coating than anything else

Did they move down the z32 e-brake bolting holes? (I presume)
That's a good idea
btw, if the bushing diameters are OEM size
you can press them out and install spherical bearings in them
the holes need to be precise though because, as we found out the hard way,
a few thousand off on the bushing diameter is all it takes between a press fit and a mangled bearing

I won't have a chance to install the rear knuckles yet and it might be a while till I do. According to Driftworks the z32 ebrake should be bolt on with the exeception that the left and the right are swapped. I'll know when I attempt to do the install.

Sounds, looking forward to it

[GripTerror]

Please install and review Asap

[udon!]

ok if i have a slaamed car how much of a difference is it going to make if i get roll center correction knucles? is it going to be a MEGA difference or a average difference.

[mmdb]

Mano,

Here's a picture of the caliper coverage...



Looks to be A OK. As far as the axle, it looked to be perpendicular to the hub. When you develop your spindles you're more than welcome to check these out in person.

Ok got the other knuckle installed, but while I was installing it I ran into a problem. The axle was a tad oversized (about 5 hundredth of a mm). I just ended up sanding it down. no biggie... I'll have to send Driftworks an email bout it for future reference.

My first impression is very positive. I was worried the car would be very twitchy at the steering wheel due to the shorter arm lengths, but to my surprise the car felt very stable during turn in and very confidence inspiring. I also enjoyed the ability to throw the car in the corner and while the car remained flat. I noticed I hit higher speeds going into regular routes I take around town. I did notice I had a faster steering ratio. This might be good/bad for some, but I enjoyed it.

I did feel the rear wanting to roll over while hitting nearing the limit during a turn. I can't wait to have them installed... maybe in a few weeks I'll be able to. There's a few things I need to do in order to get it prepped (ie get new rear shock mount, oem rear arms, etc). It should definitely transform the car's handling big time.

I'll need to provide pictures of this later, but just from eying it, the pickup points for the LCA look to be parallel to the ground. I noticed this was the case when I was running my GP Knuckles with the Moonface Roll Center adjusters. Though in contrast, the Driftworks (DW) had more shock travel during compression allowing me to rid of the the abrupt understeer due to, what I believe, lack of compression travel. I have to thank DW for keeping that in consideration.

As far as ride height... WOW. The car is low (I'll post pix later). When they designed these they where meant for a straight up race/drift car... luckily I don't think there's any huge pot holes on the race track to require the suspension to drop more than a 3-4"... *fingers crossed*

[racepar1]

Ok, time for the Driftworks criticism...

It seems that what they did was simply move the hub mounting points up somewhere around 1.5"-2". All the other suspension mounting dimensions look to be exactly the same as stock, with the notable exception of the front tie rod mounting points. In the rear that is probably pretty close to ideal as long as your coilovers have enough adjustment to compensate. By "ideal" I am referring to the method with which the roll center was corrected, not necessarily the amount. In the front though I think that method may cause problems. Remember that in the front the limiting suspension travel factor is the wheelwell, not the suspension itself (ESPECIALLY on s-13's). With these knuckles your front suspension has between 1.5"-2" or so MORE bump travel at the SAME ride heighth. If you DON'T have 1.5"-2" MORE wheelwell clearence, you are likely in trouble.

mmdb, I would suggest that you check your wheelwell clearence if you haven't already. I am interested to find out how your front tire clearence is with these.

To check wheelwell clearence (for those who don't know) you simply remove the springs from one front and one rear coilover. Do not mess with any of the adjustment perches, just take the upper mount top nuts off. I wouldn't bother with the rear unless you have knuckles like these ones though. Re-assemble and install the coilovers without the springs on the car and install the wheels. Compress the suspension with a jack untill the car is resting on the bumpstops and check clearence. You SHOULD have just a little room to spare, like 1/8" or so at least but not more then maybe 1/4". Front bump travel is ridiculously limited so you've gotta be pretty close. knuckles.

Remember guys that real suspension "tuning" is all about the complete package. Sure you can throw coilovers and basic adjustable arms at the car without much thought, but to REALLY correct the geometry and maximise travel every single part and piece has to be DESIGNED to work with EACHOTHER. Just because a part works awesome for someone else doesn't necessarily mean that it will work for you. This statement is not directed towards anyone specifically, it is just a general statement that everyone needs to REALLY hear.

[GripTerror]

mmdb im looking forward to the full review... great so far!

That's awesome to have increased bump travel, shock travel...! I am concerned now running my 6" front springs, may need 7" up front then I guess.

[ManoNegra]

excellent Jimmi
positioning of the caliper looks dead on

[Def]

Originally Posted by racepar1

Ok, time for the Driftworks criticism...

It seems that what they did was simply move the hub mounting points up somewhere around 1.5"-2". All the other suspension mounting dimensions look to be exactly the same as stock, with the notable exception of the front tie rod mounting points. In the rear that is probably pretty close to ideal as long as your coilovers have enough adjustment to compensate. In the front though I think that may cause problems. Remember that in the front the limiting suspension travel factor is the wheelwell, not the suspension itself (ESPECIALLY on s-13's). With these knuckles your front suspension has between 1.5"-2" or so MORE bump travel at the SAME ride heighth. If you DON'T have 1.5"-2" MORE wheelwell clearence, you are likely in trouble.

mmdb, I would suggest that you check your wheelwell clearence if you haven't already. I am interested to find out how your front tire clearence is with these.

To check wheelwell clearence (for those who don't know) you simply remove the springs from one front and one rear coilover. Do not mess with any of the adjustment perches, just take the upper mount top nuts off. I wouldn't bother with the rear unless you have knuckles like these ones though. Re-assemble and install the coilovers without the springs on the car and install the wheels. Compress the suspension with a jack untill the car is resting on the bumpstops and check clearence. You SHOULD have just a little room to spare, like 1/8" or so at least but not more then maybe 1/4". Front bump travel is ridiculously limited so you've gotta be pretty close. knuckles.

Remember guys that real suspension "tuning" is all about the complete package. Sure you can throw coilovers and basic adjustable arms at the car without much thought, but to REALLY correct the geometry and maximise travel every single part and piece has to be DESIGNED to work with EACHOTHER. Just because a part works awesome for someone else doesn't necessarily mean that it will work for you. This statement is not directed towards anyone specifically, it is just a general statement that everyone needs to REALLY hear.

I disagree.

I've said it about 20 times here, but I'll say it again, the rear roll center does NOT drop as quickly as the front when lowering the car. Raising the rear roll center up to almost stock height when you've lowered the rear CG a few inches is going to create an UNFAVORABLE roll axis inclination in that it crosses through your CG axis. This causes all sorts of undesirable things to happen with your suspension.

I still have no clue why people think going to stock geometry is the right thing to do when you've now lowered your CG significantly. These two things work together, why in the world would you want to keep one the same and change the other one significantly?

[racepar1]

Originally Posted by Def

I disagree.

I've said it about 20 times here, but I'll say it again, the rear roll center does NOT drop as quickly as the front when lowering the car. Raising the rear roll center up to almost stock height when you've lowered the rear CG a few inches is going to create an UNFAVORABLE roll axis inclination in that it crosses through your CG axis. This causes all sorts of undesirable things to happen with your suspension.

I still have no clue why people think going to stock geometry is the right thing to do when you've now lowered your CG significantly. These two things work together, why in the world would you want to keep one the same and change the other one significantly?

I was referring to the method used to correct the roll center, not necessarily the amount. You know damn well that I know exactly what you posted above is true. That was a big damn topic in my thread on NRR and the main reason why I created the thread in the first place. I have a lot of respect for your knowledge and abilities but you are really becoming a pain in the ass. If you wanna clarify my post, that's fine, but enough with the argumentative bullshit from you.

EDIT: There, I edited my other post to clarify EXACTLY what I was talking about.

[mmdb]

Here's how the car sits right now. If I had an adjustable perch I would raise it up a little bit.

Here's the arms (camera not level, and the lens is causing distortion)

. It looks to be almost parallel with the ground.

[Def]

Originally Posted by racepar1

I was referring to the method used to correct the roll center, not necessarily the amount. You know damn well that I know exactly what you posted above is true. That was a big damn topic in my thread on NRR and the main reason why I created the thread in the first place. I have a lot of respect for your knowledge and abilities but you are really becoming a pain in the ass. If you wanna clarify my post, that's fine, but enough with the argumentative bullshit from you.

EDIT: There, I edited my other post to clarify EXACTLY what I was talking about.

I responded to your comment exactly as it stands. Or does "pretty close to ideal" mean something other than it obviously says? Fine you didn't mean it exactly like you wrote it, no need to start with hysterics because I said I disagreed with something you wrote.

I didn't come out and start attacking you, so stop being such a pussy about a completely beneign comment. Go whine to someone that gives half a shit about you getting overly emotional if that's what you feel you've got to do whenever I quote a post of yours.

[GripTerror]

Guys cut it out lets be nice.

mmdb that looks bad ass

[Ghostdrifter]

I have two questions:

1) How do you determine the CG(particularly on a 240)?
2) How do you determine the roll center?

[racepar1]

Originally Posted by Def

I responded to your comment exactly as it stands. Or does "pretty close to ideal" mean something other than it obviously says? Fine you didn't mean it exactly like you wrote it, no need to start with hysterics because I said I disagreed with something you wrote.

I didn't come out and start attacking you, so stop being such a pussy about a completely beneign comment. Go whine to someone that gives half a shit about you getting overly emotional if that's what you feel you've got to do whenever I quote a post of yours.

Every single time you quote one of my posts, on whatever forum, out comes your condsecending attitude. You talk about how you know so much better about everything. I'm not so convinced that you do actually know better about very much. The kids on NRR just love to stroke your dick, well this ain't NRR. You are neither as smart nor as cool as you think you are. You can call me a "pussy" and "emotional", but I'm just getting sick of the condescending attitude from you. Besides if I REALLY wanted to insult you I could do MUCH better then "pussy" or "emotional".




mmdb, have you checked the wheelwell clearence yet? I am super interested in seeing how that turns out...

[racepar1]

Originally Posted by Ghostdrifter

I have two questions:

1) How do you determine the CG(particularly on a 240)?
2) How do you determine the roll center?

Read Sport Compact Car magazines "Make It Stick" articles. I believe "part 4" has the discussion on roll center. CG involves jacking up the car a certain amount and recording the weight transfer as far as I know, but I really can't get into detail there. The bottom line is that if you wanna know those kinds of things why in the fuck are you asking on a forum? Pick-up a damn book! That'll teach you a lot more then a bunch of internet idiots. Also I'm pretty sure that the info you requested could be very easily found on google.

[mmdb]

Def & racepar you two should have a PM war rather than post up in the forum, unless it's contributing to the topic.

Originally Posted by racepar1

mmdb, have you checked the wheelwell clearence yet? I am super interested in seeing how that turns out...

Nope not yet. I haven't scrapped my inner wheel well so things are gravy so far. Running 8kg/mm up front without bottoming out. I'll get around to it some day. Been too busy with other things.

Originally Posted by Ghostdrifter

I have two questions:

1) How do you determine the CG(particularly on a 240)?
2) How do you determine the roll center?

There's a few online sources out there. More than likely if you search for "roll center" you'll learn about CG as well as they work hand in hand with each other.

Here's the rear of my car's RLCA pickup points with the moonface roll center adjuster, bout a 12mm gap in between my tire and outer fender running on 285/30/18 tires.

From eying it the pick up inner and outer pickup points look to be 6.25" and 6.5" outer respectively. The outer is a little tricky because the pivot point in the pillow ball is obviously sealed.

[GripTerror]

Does the car feel more compliant/comfortable/grippy so far in the front (I know you didnt install the rears).

Give us some beef on how it feels so far Cmon And I wouldn't raise it that's like perfect

[Def]

Originally Posted by racepar1

Every single time you quote one of my posts, on whatever forum, out comes your condsecending attitude. You talk about how you know so much better about everything. I'm not so convinced that you do actually know better about very much. The kids on NRR just love to stroke your dick, well this ain't NRR. You are neither as smart nor as cool as you think you are. You can call me a "pussy" and "emotional", but I'm just getting sick of the condescending attitude from you. Besides if I REALLY wanted to insult you I could do MUCH better then "pussy" or "emotional".

You've got to be fucking kidding me...

If you want to debate things, fine, debate it in a technical manner, but stop with the drama.

BTW - since you called out my technical understanding, I'll just go ahead and say the only reason why it looks that way to you is that you know as much about engineering as I do about brain surgery(which isn't much).

[Def]

Back to the discussion at hand... what's the weight on the rear uprights? I weighed Z32s at about 6.5 lbs less than stock iron uprights per side.

[mikerbike]

MMDB, what shocks are you using? You can't raise ride height? Or you can't raise ride height enough to compensate how much the spindle raised the wheel?

On Topic, I tried 'super low' ride height on my car for a few weeks, maybe 2 months, i don't remember. The front gave me troubles at full lock, the rack didn't center itself and in the rack started moving side to side under turning load. The rear didn't feel any different. I raised the front one collar width (8mm or so) and it fixed all three problems. Definitely not worth the style.

Sadly, the reason I raised it was so I could fit a taller tire, not because I had problems. Stupid drifter..

[PoorMans180SX]

Originally Posted by racepar1

Ok, time for the Driftworks criticism...

It seems that what they did was simply move the hub mounting points up somewhere around 1.5"-2". All the other suspension mounting dimensions look to be exactly the same as stock, with the notable exception of the front tie rod mounting points. In the rear that is probably pretty close to ideal as long as your coilovers have enough adjustment to compensate. By "ideal" I am referring to the method with which the roll center was corrected, not necessarily the amount. In the front though I think that method may cause problems. Remember that in the front the limiting suspension travel factor is the wheelwell, not the suspension itself (ESPECIALLY on s-13's). With these knuckles your front suspension has between 1.5"-2" or so MORE bump travel at the SAME ride heighth. If you DON'T have 1.5"-2" MORE wheelwell clearence, you are likely in trouble.

I'm pretty sure the wheel well clearance issue would only be an issue if you were already bottoming out your shocks at the ride height you were at. Also, you are going to have more roll resistance when you raise your roll center, so this will decrease the likelihood of you running into interference issues during bump.

I'm most interested to see what the rear looks like at ride height with the knuckles.

So here's the issue I'm having. Roll center drops slower in the rear, but how is it determined? Don't the other arms have an affect on roll center location?

How is roll center measured in the rear on a Nissan multilink? I've been searching google for like 20 minutes and haven't been able to find anything except stuff about double wishbones and solid axles.

Also, for the front suspension, lets not forget that the angle of the tension rod has an affect on the amount of anti-dive the car has. Anti-dive obviously affects weight transfer and it's speed, which affects front and rear traction under braking.

From what I understand, drop knuckles will increase dive some, which should help front traction during trail braking, and help with initiating a drift using the brakes.

Also, found some good info here, cool pics of some V8 supercar suspension.

The Roll Center Thread (bump steer too) - Hardtuned.net - Page 3