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

[xpertsnowcarver]

In regards to the DriftWorks knuckles for the front and rear, would they be suitable for road racing? I apologize if this has been answered. There is just such an overwelming amount of awesome in here that I just want to make sure that I am understanding correctly.

I understand that the pivot points between the FLCA and Tie Rod are closer, causing the inner facing wheel (pointing towards inner radius of a corner) to have more angle inward than the outer wheel. (As much as 5deg difference.)

I believe, since I do not have my roll centers modified, that my outer wheel has more angle inward than my inner wheel. (Really bad right?)

Is having the inner wheel with more angle inward more beneficial for road racing? I'm picturing my car in a corner, accounting for the weight of the vehicle on the outside, and it seems that I would benefit. I just want to confirm that I am thinking correctly.

Or, would I incorporate the Offset Rack Spacers they make so that the directions of the wheel are identical?

Lastly, would combining the DriftWorks knuckles with Moonface roll center adjusters be overkill?

[SicBastard]

So you're dropping the tie rod link, but not raising the spindle? I understand that half of these knuckles are for drifting, but a little extra effort for the better camber curves would help entry speed.

[xpertsnowcarver]

^^Who me?? No. I want everything to be symmetric and ideal for road racing.

[SicBastard]

no, in response to kpr and billspear

[SoSideways]

Those guys are basically just cutting up the stock knuckles and rewelding them with the arms that the tie rods bolt up to being shorter and with a "flatter" angle, thus allowing the knuckles to be able to spin around more before they touch the FLCA as the tie rods pull them in.

Because of that, there is just not enough material to cut up and reweld on the back side where the FLCAs would bolt up to, thus not able to add any roll center correction in that sense.

To correct roll center with stock or stock-like knuckles, the most cost effective way to do it would be to do what Def did and modify Godpseed FLCAs and do it up that way.

Or you could take out the stock ball joints in your stock FLCAs and weld in spherical bearing cups and put spherical bearings there, then use a 3/4" bolt in place of the ball joint or the tapered stud. Makes life a million times easier.

Then all you'd have to worry about at that point would be the tie rod ends.

[ManoNegra]

Originally Posted by xpertsnowcarver

In regards to the DriftWorks knuckles for the front and rear, would they be suitable for road racing? I apologize if this has been answered. There is just such an overwelming amount of awesome in here that I just want to make sure that I am understanding correctly.

Or, would I incorporate the Offset Rack Spacers they make so that the directions of the wheel are identical?

They were *cough* 'developed' *cough* for drifting but do address roll center
Jimmy mostly tracks his car so he would be the best person to ask
once his knuckles are done
on that note, Mike started making the one-off bushings for them
I'll try post up some pics tomorrow

Joel, stay away from those rack spacers, that's some scary shit

aren't you an engineer? Design me a structurally sound modular aluminum upright
kind of like the ones on the Sierra Sierra Time Attack Evo
and I'll be your best friend

[mmdb]

Originally Posted by xpertsnowcarver

In regards to the DriftWorks knuckles for the front and rear, would they be suitable for road racing? I apologize if this has been answered. There is just such an overwelming amount of awesome in here that I just want to make sure that I am understanding correctly.

I would highly recommend a roll center adjuster similar to what the Driftwork spindles achieves. I like them a lot (front only right now) not only because they add a sharper feel with much, much less roll, but also because the steering arm was modified. THis decreases the steering ratio which I found beneficial during turn in (arms aren't crossed up) and during oversteer correction (fast steering ratio helps a lot with reaction).

Originally Posted by xpertsnowcarver

Lastly, would combining the DriftWorks knuckles with Moonface roll center adjusters be overkill?

The amount of correction the Driftworks knuckles is plenty. Addition of the Moonface roll center adjuster is overkill. BUt doesn't hurt to try if you're curious, just your wallet.

[ManoNegra]

The first of the custom bushings for the Driftworks rear knuckles

[SicBastard]

Are the driftworks rear knuckles made out of aluminum?

[longfellow]

No they're steel.

[GripTerror]

With the light rekindled, engineers jump in and make stuff for us

[xpertsnowcarver]

Originally Posted by ManoNegra

They were *cough* 'developed' *cough* for drifting but do address roll center
Jimmy mostly tracks his car so he would be the best person to ask
once his knuckles are done
on that note, Mike started making the one-off bushings for them
I'll try post up some pics tomorrow

Joel, stay away from those rack spacers, that's some scary shit

aren't you an engineer? Design me a structurally sound modular aluminum upright
kind of like the ones on the Sierra Sierra Time Attack Evo
and I'll be your best friend

http://photos.motoiq.com/MotoIQ/Feat...2_2TLxp-X2.jpg

Which Jimmy are you talking about? I know more than one on here.

Yea, I wasn't looking forward to using those. I'm sure they cause a lot of stress at the joints.

Lol! Man, if I had a Mill, let alone access to one, then yes, I would make some kind of forged upright. I began designing one, but I became too busy with other things.

Originally Posted by mmdb

I would highly recommend a roll center adjuster similar to what the Driftwork spindles achieves. I like them a lot (front only right now) not only because they add a sharper feel with much, much less roll, but also because the steering arm was modified. THis decreases the steering ratio which I found beneficial during turn in (arms aren't crossed up) and during oversteer correction (fast steering ratio helps a lot with reaction).

The amount of correction the Driftworks knuckles is plenty. Addition of the Moonface roll center adjuster is overkill. BUt doesn't hurt to try if you're curious, just your wallet.

Uggh... They are expensive..

[racepar1]

Originally Posted by ManoNegra

Joel, stay away from those rack spacers, that's some scary shit

aren't you an engineer? Design me a structurally sound modular aluminum upright
kind of like the ones on the Sierra Sierra Time Attack Evo
and I'll be your best friend

Sorry, I just messed my pants a little.

Ya, make those and I'll be your best friend too.

[GripTerror]

Me three .

[ManoNegra]

Originally Posted by xpertsnowcarver

Which Jimmy are you talking about? I know more than one on here.

Jimmy <--> mmdb

Lol! Man, if I had a Mill, let alone access to one, then yes, I would make some kind of forged upright. I began designing one, but I became too busy with other things.

Uggh... They are expensive..

I just need a well thought out design, leave the rest to me

[xpertsnowcarver]

Originally Posted by ManoNegra

Jimmy <--> mmdb

I just need a well thought out design, leave the rest to me

OOOHH YEA! I forgot. That's another Jimmy. I'll bug him right now.

Oh, well that's not too hard. Do you have the SolidWorks program? If not, it's cool, I can send you drawings in PDF format.

[wacko2]

that for all the info

[Z33dori]

So me and my friend were having a debate on how you want your leading wheel while your at full lock. He thinks that you would want your wheel to still roll over to positive so that it will pull the car in that direction, based off the fact of your wheel always pulls to the side that is most positive while driving straight.

I think that you would want the wheel to roll flat. I based this off setups that run lots of static negative camber with higher than stock caster. B/c this will put you closer to 0 then if u had less, correct.

So which is right?
Flat>

or more towards positive>

[SoSideways]

Probably a personal preference thing there...

Some might like it to be flat, some might like it to be more positive.

[PoorMans180SX]

Flat gives you much more grip. You have to think, basically that is the only wheel steering your car at that much angle. The weight is on that side, and the other tire is going to go up on it's side too.

Static camber will not change your steering axis inclination unless you dial it in using the lower mounts on your coils. Think about how your wheel moves around your shock.

Caster will make the wheel roll over onto it's edge more because the shock is more angled.

Now you can modify all these things, but be careful, you have to take into account ackerman and scrub radius as well, so be smart if you're going to do it.

[mikerbike]

So, I tried those modified knuckles like Bilspeer and KPR and LOVED them. I didn't remove the stops on my control arms, so I didn't gain much angle (some) but the steering response is what I would consider "amazing". Now I have both of my S13s equipped with them. Yeah, love them.

[95KA-Turbo]

Sorry if this was mentioned somewhere, I didn't relook through the thread.....but D-Max makes knuckles now:



D-MAX Æ’Vƒ‡Â�[Æ’g Æ’iÆ’bÆ’Nƒ‹Â�@Â�Ø‚êÅ*pÆ’AÆ’bÆ’v | Æ’GÆ’AÆ’Â�‚Ȃǂ̃hÆ’Å*Æ’tÆ’gÆ’`ƒ…Â�[ƒ“ƒpÂ�[Æ’c

Looks like they have a nice bumpsteer correcting dip in them too.

[SoSideways]

They definitely do have some nice bumpsteer correction built into those.

But for dudes like you and me, Def, mmdb, Codyace, and Otto, we're also using roll center correcting FLCAs, so just that little bit of bumpsteer correction from those knuckles are still not enough to totally eliminate bumpsteer.

You would still need the adjustable tie rod ends.

[Z33dori]

by adj you mean like the Kazama and stance "angle" tie rod ends?


And do knuckles increase caster, or is it just the added steering angle rolls so much futher?

[SoSideways]

Caster is controlled by the T/C rods normally, as your knuckles rotate on the ball joints (or spherical bearings) on the FLCAs, so no, those knuckles that are basically just stock ones that are cut and rewelded do not change your caster at all.

And by adjustable, yes, I mean like the Kazama or Stance tie rod ends, although those don't have nearly the amount of adjustments that the SPL Parts ones will give you.

[xpinoyxmk]

Sorry dont know if its been covered either but Dmax tie rod ends and the turning up angle adaptor info pls.

[Pandapants]

What about peak performance outers?
Their shank looks comparable in size to the spl
but at a fraction of the price and compatible with s14 inners.

I was looking through the nissan road racing forum mentioned earlier,
and many were saying that roll center adjusters like moonface and greddy
don't really change roll center "b/c of the location of the pivot point."
Are there any pictures out there with either of these products next to a stock balljoint to compare the location of the pivot points?

[PoorMans180SX]

Originally Posted by Z33dori

by adj you mean like the Kazama and stance "angle" tie rod ends?


And do knuckles increase caster, or is it just the added steering angle rolls so much futher?

Another reason I'll be getting Driftworks knuckles. The steering axis inclination is modified to keep the tire flat when at extreme angles. Check it:

[Z33dori]

Originally Posted by PoorMans180SX

Another reason I'll be getting Driftworks knuckles. The steering axis inclination is modified to keep the tire flat when at extreme angles. Check it:

thank you so much i was trying to find pix like that last night to prove that they keep flat.

much appreciated. Yea the more i look into those geomaster knuckles the more they are worth the heavy price.

[PoorMans180SX]

Originally Posted by Pandapants

What about peak performance outers?
Their shank looks comparable in size to the spl
but at a fraction of the price and compatible with s14 inners.

I was looking through the nissan road racing forum mentioned earlier,
and many were saying that roll center adjusters like moonface and greddy
don't really change roll center "b/c of the location of the pivot point."
Are there any pictures out there with either of these products next to a stock balljoint to compare the location of the pivot points?

Look on the first page. Sunline racing ball joints actually have a longer shank.

I'm sure peak performance outers are very high-quality. SPL's are compatible with S14 inners, they just like to tell you they're not so that you buy inners from them.