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

[GripTerror]

Running 295s up front and low offset... wouldnt we want KPI and scrub radius adjusted (for grip/track setup) and also to improve braking stability as braking gets all shitty and snappy...

[Motary]

Originally Posted by My$800S14

Depends on the size of the scrub radius, once it gets to an extreme some steering situations offer easier steering effort, and I forgot about the jacking, but do you really think that adverse effect outweighs the disadvantages of excessive caster? Because my hopes were to use some inward sai to compensate for the lower caster that I was intending to run.

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That is up for you to decide since it is your personal car and you can always change it if you dont like it.

[My$800S14]

Originally Posted by GripTerror

Running 295s up front and low offset... wouldnt we want KPI and scrub radius adjusted (for grip/track setup) and also to improve braking stability as braking gets all shitty and snappy...

I'm not following grip terror, are you saying that is what you are running?

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[GripTerror]

i have 18x11 up front with 295/30/18... low offset i forget exactly now to fill out bn blister fenders.... kind of like that one black time attack except it uses s15 front on s13 hatch chassis.. same front width though...

Anyways... with lower offset... braking is shaky... and steering effort is greater with obviously heavier/wider tires and the scrub radius in question...

I dont have any of these fancy knuckles but contemplating... and what would be the ideal for a wider grip setup with low offset like that...

[My$800S14]

I'm going to guess that a good thing for you to do would be to extend your lca and bring the top mounting point of your strut out, and run a less aggressive offset? Just extending your lca should lower your scrub radius by making your sai a little steeper and likely bringing closer to the center of your contact patch, BUT then you would have excessive camber

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[My$800S14]

A 295 does sound excessive though as far as practicality goes I could be wrong, and I understand your need to fill the fender Aswell

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[GripTerror]

grip, downforce, traction are things people care in road racing and time attack Not going thinner

[My$800S14]

Originally Posted by GripTerror

grip, downforce, traction are things people care in road racing and time attack Not going thinner

Heard, understood, and agreed, but if you can't use the width of a rim&tire combo to its potential its useless, how low is your car?

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[nieko]

^^^^^ Exactly. It's like buying a big brake kit and running 195's. That isn't going to do shit. lol

[delado]

Anybody got any feed back on battle version arms?

Trying to get arms for my daily s14. Ideally I would want PBM/SPL but kind of on a budget.

[jaysgottaredtop]

how has this not been posted yet? another cool product idea from GKTech for the s-chassis.



pros: inexpensive, uses the stock knuckle, corrects roll center, corrects bumpsteer, widens track, adds more negative camber, any ackermann angle possible depending on where they drill the new tie rod pickup hole.

cons: heavier than a cut/weld knuckle or GKTech's billet knuckles, increases scrub radius.

what else am i missing? obviously the geometry isn't 100% ideal, but it seems to nail all the basics in a concise package. are there any specific reasons to avoid this design entirely, besides guys doing high level competition?

overall this looks like an AWESOME product idea for grassroots drifting. cheaper than modded knuckles, no downtime (since you don't need to send your knuckles out), corrects roll center and bump steer, and it's got that all-important billet gansterness.

what say you, suspension geometry geeks?

[godrifttoday]

That looks sweet, I still would want the new aluminum knuckle they did

[Bushido]

those bolt on jams are going to be around $250... im sold

[edmorl]

any eta on those ?

[jaysgottaredtop]

^ according to their FB page: sub-$250 (AUD i assume, but AUD and USD are nearly the same value right now), and ETA mid 2013.

[My$800S14]

Those look like they are placing the ball joint and tie rod pick up point at different angles than factory, which immediately effects Ackerman and the angle at which the ball joint and tie rod sit at which will allow then to reach there extremes with less suspension travel than previously, unless they are sitting that way to compensate from the added length downward and outward from factory

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[PoorMans180SX]

Originally Posted by My$800S14

Those look like they are placing the ball joint and tie rod pick up point at different angles than factory, which immediately effects Ackerman and the angle at which the ball joint and tie rod sit at which will allow then to reach there extremes with less suspension travel than previously, unless they are sitting that way to compensate from the added length downward and outward from factory

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Not really, those are almost exactly the same angle adjustments that every good aftermarket knuckle uses. No detrimental binding will occur.

[Croustibat]

I think i'll get these. Will talk to my local tuner, he may be interested in selling them here.

[nateshew]

having just moved from a Toyota to a s chassis i thought i give my 2¢ Techno toy tuning made some nrca's for the corolla seen and i really liked them. trouble is no body makes them for 240s (yet) gk looks like they are on it like stink on $hit.trouble is they live half a world away so i just made my own. any constructive criticism? hit me up on FB for a faster response. i should mention this is a prototype, any machinists out there, don't kill me, i had to find out if my numbers meshed

40mm roll center correction (could change)
1" track width gain (likely to change)
2 tierod pickups that can be moved to create 2 new locations. totaling 4 pickup points. (most defiantly going to change

Nathan Shewchuk

[PoorMans180SX]

Well man, I think you're the best judge of structural integrity, since you'll be driving with them.

You can use the chart in here a few pages back to determine what your total roll center correction needs to be.

You can experiment with the tie rod pickup holes and figure out where you want yours, then make a final design with just that hole so it can be simpler if you wanted to.

TO ALL: I've been REALLY slacking on getting that first page updated. Look for it in the coming week.

[nateshew]

thanks! ill take a look back a few pages as for strength, this is a wonky prototype, i have some tricky plans for the next rev. still working on inserts, id like to have pres-fit inserts for the lower balljoint. also my boss pointed out a few things and some big changes are in the works i can say this. i have changed from 4 too 16 tierod pickups per block >.<

[Croustibat]

Dont forget you need to fit a wheel and a disc brake in there. I wanted to get the gktech version of these, but it will hit my brake setup, so i am back to square 1.

[tauntdevil]

Awesome, hope the front page mentions how much to shorten the tie rod point on the knuckle and what not. Been looking for how much people normally shorten them but cant find much. Guessing 30mm but I dont know.

[nateshew]

Croustibat
what setup have you got? brake wise? im checking clearance against stock s13 and z32 bits. i have designed it so that if it cleared a stock lca in the first place it should clear this, unless its some off the wall NASCAR brembos or something
>.<

[Croustibat]

I got 330x32mm rotors from a ferrari 456 GT/A and wilwood superlite 4pots calipers.

My current lower arms are only a couple millimeters from the disc, and i cant fit that kind of hardware. Cant fit ball joints with longer shank either for the same reason ... i guess i will have to change my brake setup someday.

[Motary]

Originally Posted by tauntdevil

Awesome, hope the front page mentions how much to shorten the tie rod point on the knuckle and what not. Been looking for how much people normally shorten them but cant find much. Guessing 30mm but I dont know.

How much steering angle do you want?

[ka-titties]

Originally Posted by Motary

How much steering angle do you want?

[Motary]

Looks like good news for usa guys, wisefab working on a Formula Drift legal kit

[Matej]

Originally Posted by jaysgottaredtop

How much angle and camber will this add? Any specific or estimated numbers?
I want to buy a set right now. Hope it comes out soon.

[PoorMans180SX]

Originally Posted by Matej

How much angle and camber will this add? Any specific or estimated numbers?
I want to buy a set right now. Hope it comes out soon.

It will add as much angle as a driftworks knuckle. I'd say this is the best idea they've thought of. They'll be selling out of these for months at a time.