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

[ghoti]

[rawgarage]

Damn GKTEch

[PoorMans180SX]

Meh, I agree with a lot of the video but the dude seems to want to make some mountains out of mole hills.

[GKTECH]

We weren't offering a refund to someone to "keep their mouth shut", we simply asked if he would mind removing the post on here as the issue was now resolved. It was in no way a condition of the discount that we offered for the trouble he encountered. We use these product on our own cars and the last thing that we want is trouble when installing the parts however given it was an easy fix, the discount is what we offered. Had the customer not been happy with this or preferred to swap it for another set we would have happily done so.

We didn't hear anything in response. Then this?

[Motary]

Originally Posted by ghoti

Not good enough for S-chassis

but..

Good enough to win Le Mans 24h (tie rod, pushrod)

[PoorMans180SX]

Awwwwwwwww shiitttttt

REKT!

Hahaha.

[ditchs14]

yeah that guy kinda half knows what hes talking about..... like he never compares how much adjustment the arms give you.

[ka-titties]

I'm actually a huge fan of the double locks on the PBM rods. Jam nuts loosen all the time.

And... I don't know how you consider the locking mechanism on the GKTech arm to be "half done." All you need to do is lock the bigger half of the adjuster... the smaller half won't move, its bolted to the chassis.

[jackb77]

What the pro / cons of this strut top position?
Is this right to have more caster?

[GKTECH]

Originally Posted by Bnr32gtr

Az 240 what ruca you running now? I seen u sold the gk. I just installed mine no way will they work I raised the rear over 1" and the gk ruca bent type are still laying on axle boot. Also have sub frame risers and gk tech rear knuckles.

What chassis bnr32gtr? I run the bent arms on my S14 with the subframe raised and with the gktech rear knuckles and I don't have any clearance issues with the axle boot. I'm not super low but couldn't go much lower while having atleast some shock travel.

[Jorgs_7]

Originally Posted by ghoti

That dude is a complete squid.

I have too many points to blow his bullshit out of the water. He's clearly not an engineer, or even close to being one, or thinking like one.

But if you own an S-chassis and know "stuff" about the racing "scene", then you MUST be smart, right?

[Motary]

Originally Posted by jackb77

What the pro / cons of this strut top position?
Is this right to have more caster?

You gain caster, but lose steering axis angle.

Steering axis angle causes jacking through steering angle, its beneficial for racing, hurtful for drifting when trying to gain more contact patch. In racing it helps to increase negative camber (when steering) that is otherwise lost due to bodyroll.

With MacPherson strut layout you also increase scrub radius, increasing steering effort, scrub and self-alignment torque.

[jackb77]

Originally Posted by Motary

You gain caster, but lose steering axis angle.

Steering axis angle causes jacking through steering angle, its beneficial for racing, hurtful for drifting when trying to gain more contact patch. In racing it helps to increase negative camber (when steering) that is otherwise lost due to bodyroll.

With MacPherson strut layout you also increase scrub radius, increasing steering effort, scrub and self-alignment torque.

I try to understand what the best setup for drifting but I'm a bit confused.
It's better to line it like stock? I buy these becouse I have long lower control arm

[Motary]

Originally Posted by jackb77

I try to understand what the best setup for drifting but I'm a bit confused.
It's better to line it like stock? I buy these becouse I have long lower control arm

If you are confused, first try original setting by moving the top of the strut out equally to the balljoint. Since the setup for drifting tends to be very personal, you have to find it out for yourself. I would run 5-6 degrees of caster and 3-4 degrees of negative camber. Less caster is more tyre contact patch at lock, but less self steer. Self steer could be increased by increasing scrub radius too. You could do that with wheel offset, wheel spacers or by moving top of the strut more outside than you have done with the balljoint and correct camber at the knuckle/strut connecting bolts, like camber is adjusted with original suspension components.

[ezza]

I was hoping someone could help me out, im struggling to find any concrete info/figures on this, i have my s13 off the road for an overhaul and figured i may as well do some hub mods.
Iv made a jig to give me the oem positions of the steering pickup in relation to lca pickup, can anyone tell me how much i should move the steering pickup inwards?

I have made some 40mm extended arms also to go on.

20160419_214618 by Aaron Beck, on Flickr

[sr vegas 240]

Anyone with gktech v3 knuckles and gktech lcas can help me out so finally got it all together and getting some bind in the steering feels heavy from center that can be due to rack going bad but it won't go full lock wheels are not rubbing on anything plenty of room. With the car jacked up it goes lock to lock on ground it won't do it binds up pretty bad. Any ideas what could be causing this? I don't have alignment done but pretty sure that wouldn't do it.

[stuckonfresh]

Originally Posted by sr vegas 240

Anyone with gktech v3 knuckles and gktech lcas can help me out so finally got it all together and getting some bind in the steering feels heavy from center that can be due to rack going bad but it won't go full lock wheels are not rubbing on anything plenty of room. With the car jacked up it goes lock to lock on ground it won't do it binds up pretty bad. Any ideas what could be causing this? I don't have alignment done but pretty sure that wouldn't do it.

The "heavier" steering is normal because I believe the arm that comes out of the knuckle that the tie rod attaches to is shorter than the OEM arm; therefore, there is less available leverage working to help steer the knuckle.

As for the binding I would use your steering bump stops to keep steering in "usable and unbinding" range. Alternatively one could find a way to prevent overcentering within steering range, such as moving steering rack forward.

I know you prob know this already, but for anyone who doesnt: Steering overcentering, has to do with three points in the steering mechanism
point 1-steering rack to tierod
point 2- tierod end to knuckle
point 3- pivot point of the knuckle, knuckles' attachment to flca

If an imaginary line is drawn between point 1 and point 3, point 2 should never cross over this line or steering bind will occur.

.

[sr vegas 240]

Would 2" spacers cause it reason I'm using them is because I only have stock g35 rims at the time.

[sr vegas 240]

Originally Posted by stuckonfresh

The "heavier" steering is normal because I believe the arm that comes out of the knuckle that the tie rod attaches to is shorter than the OEM arm; therefore, there is less available leverage working to help steer the knuckle.

As for the binding I would use your steering bump stops to keep steering in "usable and unbinding" range. Alternatively one could find a way to prevent overcentering within steering range, such as moving steering rack forward.

I know you prob know this already, but for anyone who doesnt: Steering overcentering, has to do with three points in the steering mechanism
point 1-steering rack to tierod
point 2- tierod end to knuckle
point 3- pivot point of the knuckle, knuckles' attachment to flca

If an imaginary line is drawn between point 1 and point 3, point 2 should never cross over this line or steering bind will occur.

.

I have some offer rack spacers but moving the rack forward is on my to do list

[PoorMans180SX]

245/40/17 on a 17x8.25+10. Exactly what I wanted!

[Bnr32gtr]

Gk tech, it's a s14 the car is low was tucking rim raised it 3/8" above 18" wheel lip so still pretty low. Camber is -1.5. The gk tech bent type v3 camber arms lay on Alex boot. I should have bought the straight one since I already notched my frame or bought voodoo13 they have less bend/ angle to them. Live and learn

[ezza]

finished my hubs, shout out to julian for tips on dimensions etc.

20160422_194755 by Aaron Beck, on Flickr

20160429_101850 by Aaron Beck, on Flickr

20160504_182246 by Aaron Beck, on Flickr

20160503_202438 by Aaron Beck, on Flickr

20160504_204126 by Aaron Beck, on Flickr

20160504_204135 by Aaron Beck, on Flickr

20160509_143833 by Aaron Beck, on Flickr

Anyone have tips for cleaning spindle? I got powdercoat and a little spatter on one of them

[PoorMans180SX]

Those look really good!

I'd say chip what you can off, carefully die grind any weld spatter flat, then use some 800 grit and polish it up.

[PoorMans180SX]

Originally Posted by Bnr32gtr

Gk tech, it's a s14 the car is low was tucking rim raised it 3/8" above 18" wheel lip so still pretty low. Camber is -1.5. The gk tech bent type v3 camber arms lay on Alex boot. I should have bought the straight one since I already notched my frame or bought voodoo13 they have less bend/ angle to them. Live and learn

Good to know. Guess I'll buy the straight ones.

[ka-titties]

Those knuckles came out great!

[stuckonfresh]

^agreed

I picked up some Long Acre toe plates to help "ballpark" the front alignment, not sure about the rear though- maybe "stringbox" alignment? It really just has to not be driving sideways to the shop that would do a proper alignment. Any suggestions to get the rear wheels poining straight? (not worried about camber, just toe)

[TheRealSy90]

How do you guys set up a string alignment when the front wheelbase is typically wider than the rear wheelbase with our modifications?

[stuckonfresh]

I was planning on setting up the string, taking some measurements to make sure left and right sides are parallel and the box is square; maybe 2 quick corner to corner measurements.

Then measuring the distance from the center of all four wheels (middle point of wheel cap) to the string to ensure the front pair is equidistant to the string line as well as the rear.

Even though the front and rear pair distance measurements may be different, as long as both the left and right are the same distance away from the string lines and the left and right are stringlines are parallel, one should be able to get a decent "ballpark" alignment (for toe) by then measuring the distance between the front and rear of each wheel to the string line.

[Green Arrow]

My buddy has a set of pbm v1 knuckles for cheap and im thinking about buying them, i dont really drift....Might do a few parking lot events...however im a bit confused as far as a ideal alignment goes....any reason i cant just install and go to a stock alignment?

[stuckonfresh]

nope, should be able to do a "stock alignment" as far as toe goes and should be able to do oem camber as well. The difference between the after market knuckles is usually just that:

1.the spindle, where the hub slides on sits a little higher (drop knuckles) to give lower center of gravity w/o changing suspension geo too much.

2. the acerman angle and arm length on the knuckle (where tie rod end connects) i often different than oem. A normal oem knuckle at full lock when turning will have the inner wheel turn more than the outer wheel. This helps prevent dragging or squealing at slow speed. When drifting close to zero acerman is ideal though (tierod pickup point about inline with the pivot point of the knuckle where the flca attaches) because when full lock drifting the car is movin fast, so NO tire drag is desired to maintain drifting speed.

3. bump stops should be a priority too. If using an otherwise oem front suspsension setup, other concerns may be rubbing and overcentering-stuff that a bump stop could help prevent.

so to answer your question, I believe this is possible to add aftermarket knuckles to an oem setup and maintain oem alignment, I would just keep in mind the other aspects of front geometry one would be changing by doing this.