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

[Black R]

Originally Posted by tobroketobuildarealcar

Not to be a dick but steel is speeled steel not steal that is what you are doing when you leave the store without paying

But please elaborate on the differences between cast steel and cast iron

Spelled is spelled "s p e l l e d," not speeled. :P

I think he fixed it anyway now...

Those knuckles look good!

[tobroketobuildarealcar]

Thanks I guess thats what i get for trying to type on my phone keyboard and not proof read it b4 posting

[ka-titties]

to add to the irony... you have a grammar error in your user name.


noob.

[living4surf]

have a quick question though this might of been addressed i was thinking of using the nagisa roll center correction ball joints on my rear lower arms on my s13 but was wondering if its really worth it since the rest of the arms will not be corrected in the rear. i don't know what kind of difference just correcting the lower arm arm makes good or bad

[Croustibat]

Originally Posted by living4surf

have a quick question though this might of been addressed i was thinking of using the nagisa roll center correction ball joints on my rear lower arms on my s13 but was wondering if its really worth it since the rest of the arms will not be corrected in the rear. i don't know what kind of difference just correcting the lower arm arm makes good or bad

As far as i can see they are extended ball joints, meaning they do nothing but make you spend money on items that don't do jack.

Just get new knuckles. Yes, they cost more. But they work

[living4surf]

Those specific ones actually extend the shank so the move the pivot point down so they should alter roll center and on the front they make sense to me since you can lower the tie rods too but the question is on the rear where you are now changing the angle of just one arm seems like it could do some weird things to the geometry

[Croustibat]

Originally Posted by living4surf

Those specific ones actually extend the shank so the move the pivot point down so they should alter roll center and on the front they make sense to me since you can lower the tie rods too but the question is on the rear where you are now changing the angle of just one arm seems like it could do some weird things to the geometry

The pics i saw showed the same shank length, but the pivot point was moved up due to a thicker base. If they aren't, my mistake then.

Still, get new knuckes, it will be better anyway

[shaggy0778]

From the first page:

Nagisa:

[living4surf]

Knuckles are going to happen just need to replace the ball joint anyways so. But this is also something that I haven't seen addressed yet in the rear as far as changing the geometry on the lower arm

[59bhp]

Originally Posted by ka-titties

to add to the irony... you have a grammar error in your user name.


noob.

thats not ironic, its tragic.

[D-Rock920]

Got a question, so finally getting my car back together I'm running all pbm suspension and Era one drop spindles. The problem ive ran into is the rear lca ball joint hits the wheel. Is there a different style of ball joint I could possibly run or am I force to run 18s.
im running work vsxx btw

[e30gangsta]

Alright guys I've been reading this thread and I'm super torn on which rear knuckle to go with. I'm piecing my rear end together and I currently have Pbm riser subframe bushings, along with the Isis adjustable arms in the rear. What I'm looking for is a rear knuckle that will allow me to run a separate calipers for the hydro.

From the offerings that are on the market the ones that I'm liking so far is Pbm. Gk tech also is making a nice rear knuckle. Which one would you guys go with and why?

Also is the rlca from Pbm worth it? Does it offer that many advantages over the stock unit?

Any help would be greatly appreciated. Thank you.

- G

[Bink Industries]

Originally Posted by e30gangsta

Alright guys I've been reading this thread and I'm super torn on which rear knuckle to go with. I'm piecing my rear end together and I currently have Pbm riser subframe bushings, along with the Isis adjustable arms in the rear. What I'm looking for is a rear knuckle that will allow me to run a separate calipers for the hydro.

From the offerings that are on the market the ones that I'm liking so far is Pbm. Gk tech also is making a nice rear knuckle. Which one would you guys go with and why?

Also is the rlca from Pbm worth it? Does it offer that many advantages over the stock unit?

Any help would be greatly appreciated. Thank you.



- G

circuit sport RLCA seemed to work us last season, HUGE range of adjustment. spl makes a realy nice one I like. pbm has a rod end in bending which is a big no no, spl does not.

as far as knuckles go dai and Darren both have/had spacers for the RLCA to get RC. seems to work fine for them. that being said we ran a PMB one seemed to work ok. all pick up points are in the stock location so nothing fancy there. there dual caliper mounts for the willwood mount need to be ground flush or it wont sit straight. but for the money who is complaining about a little work. gk tech just seems like a nicer version of the same thing. could be wrong.

[az_240]

I believe the pickup points were actually altered slightly on the PBM rear knuckles. I know the toe arm sure looks like it was changed. I did need to mess with the caliper brackets a bit because the brakes were wearing way crooked... they are still kinda crooked after some tweaking but it's not a big deal... pads just wear a little funny.

GK tech (40mm) is closer to the Driftworks knuckles (45-50mm) from what I can see. Only issue with that is you can't go super low or the axle joints will start to bind on themselves. PBM have 25mm of correction so can still go decently low without having this problem.

[PoorMans180SX]

Originally Posted by az_240

I believe the pickup points were actually altered slightly on the PBM rear knuckles. I know the toe arm sure looks like it was changed. I did need to mess with the caliper brackets a bit because the brakes were wearing way crooked... they are still kinda crooked after some tweaking but it's not a big deal... pads just wear a little funny.

GK tech (40mm) is closer to the Driftworks knuckles (45-50mm) from what I can see. Only issue with that is you can't go super low or the axle joints will start to bind on themselves. PBM have 25mm of correction so can still go decently low without having this problem.

PSM rear knuckles MIGHT have slight changes, but GKTech's geometry is far superior. GKtech's knuckle is closer to Wisefab's rear kit as far as geometry goes, they actually took into account where anti-squat, camber change, toe change, and roll center correction needed to be, instead of just raising the hub in the knuckle. Get some axle spacers and you should be fine as far as that goes, but if you're that low, you should probably look at better axles anyway.

[az_240]

Would you happen to know of axles that allow for more articulation? I'm interested in picking some up if you do. I know with my dw rear knuckles I couldn't go very low because of the axles... Not sure axle spacers would have done anything in that case. I would have had to raise the diff somehow or hack up the subframe to raise it some more.

[PoorMans180SX]

J30, NA Z32, or Q45/Z32TT axles allow for more articulation because of the Rzeppa CV design vs. the tripod bearing of the standard axles.

http://zilvia.net/f/showthread.php?t=555322

[az_240]

But are larger, making it difficult to fit rucas without hitting...
I guess rucas can be modified for this though..

[PoorMans180SX]

GKtech's are designed with S14 axles in mind, which are larger than the slimmer S13 boots.

[az_240]

I suppose because the arm itself is a smaller diameter..... I was just going to notch and reinforce my PBM RUCA's but may consider those depending on how much room they'll give.

Wanting to give the rzeppa 5x1 bolt j30/z32 na axles a shot now so will need all the room I can get. I assume the joints/boots are slightly smaller than the 6x1 bolt Q45/Z32tt axles but larger than s14 axles...?

[killer240]

Originally Posted by az_240

I believe the pickup points were actually altered slightly on the PBM rear knuckles. I know the toe arm sure looks like it was changed. I did need to mess with the caliper brackets a bit because the brakes were wearing way crooked... they are still kinda crooked after some tweaking but it's not a big deal... pads just wear a little funny.

I'm looking into getting some PBM knuckles. Is anyone else having this issue? I don't want to be changing pads as often than I should. Can someone chime in on this?

[az_240]

I've found if using the stock floating style calipers on a lowered car there's a good chance you'll get slight uneven pad wear if using the stock cable e-brake since it starts to pull on the caliper a bit. The way PBM lowered the caliper on their knuckles amplifies this effect... the fact that I'm running z31 caliper brackets with larger altima rotors makes it even worse. I had to reroute and secure the lines under the subframe to help correct this even after fixing the tabs on the knuckles.

I'd love to go back to Z32 brakes in the rear eventually since it's a fixed style caliper but there just aren't any options out there to keep the cable/drum E-brake until GKtech releases their rear knuckles (not doing DW knuckles again). I'm just going to keep my fingers crossed that they'll be excessive low friendly without major modification to the subframe/chassis. Highly doubtful they will be since I feel even the Rzeppa axles won't be enough to handle the extreme angles they'll be at with 40mm of correction on the knuckle alone (I'm talking on a s14 about to tuck 18" rim with stretched tires). Then there's the issue of reduced camber gain on these corrected knuckles so it's tough to get nice fitment without the tires going into the fender.

I'm about to just say screw it and go back to z32 rear knuckles, have the shock mount chopped/corrected and just deal with less traction and more bumpsteer... then again I might just raise my car a bit and run stiffer springs

[PoorMans180SX]

Originally Posted by az_240

I've found if using the stock floating style calipers on a lowered car there's a good chance you'll get slight uneven pad wear if using the stock cable e-brake since it starts to pull on the caliper a bit. The way PBM lowered the caliper on their knuckles amplifies this effect... the fact that I'm running z31 caliper brackets with larger altima rotors makes it even worse. I had to reroute and secure the lines under the subframe to help correct this even after fixing the tabs on the knuckles.

I'd love to go back to Z32 brakes in the rear eventually since it's a fixed style caliper but there just aren't any options out there to keep the cable/drum E-brake until GKtech releases their rear knuckles (not doing DW knuckles again). I'm just going to keep my fingers crossed that they'll be excessive low friendly without major modification to the subframe/chassis. Highly doubtful they will be since I feel even the Rzeppa axles won't be enough to handle the extreme angles they'll be at with 40mm of correction on the knuckle alone (I'm talking on a s14 about to tuck 18" rim with stretched tires). Then there's the issue of reduced camber gain on these corrected knuckles so it's tough to get nice fitment without the tires going into the fender.

I'm about to just say screw it and go back to z32 rear knuckles, have the shock mount chopped/corrected and just deal with less traction and more bumpsteer... then again I might just raise my car a bit and run stiffer springs

From what I've heard, the GKtech's only change ride height 20mm. The roll center correction must be done by adjusting arm position along with a hub drop or something.

[Amandrews]

Does anyone know what sizes the splines of the steering shaft and rack are? I need to buy an aftermarket u joint

[Motary]

Originally Posted by az_240

I've found if using the stock floating style calipers on a lowered car there's a good chance you'll get slight uneven pad wear if using the stock cable e-brake since it starts to pull on the caliper a bit. The way PBM lowered the caliper on their knuckles amplifies this effect... the fact that I'm running z31 caliper brackets with larger altima rotors makes it even worse. I had to reroute and secure the lines under the subframe to help correct this even after fixing the tabs on the knuckles.

I'd love to go back to Z32 brakes in the rear eventually since it's a fixed style caliper but there just aren't any options out there to keep the cable/drum E-brake until GKtech releases their rear knuckles (not doing DW knuckles again). I'm just going to keep my fingers crossed that they'll be excessive low friendly without major modification to the subframe/chassis. Highly doubtful they will be since I feel even the Rzeppa axles won't be enough to handle the extreme angles they'll be at with 40mm of correction on the knuckle alone (I'm talking on a s14 about to tuck 18" rim with stretched tires). Then there's the issue of reduced camber gain on these corrected knuckles so it's tough to get nice fitment without the tires going into the fender.

I'm about to just say screw it and go back to z32 rear knuckles, have the shock mount chopped/corrected and just deal with less traction and more bumpsteer... then again I might just raise my car a bit and run stiffer springs

The mounting points have all changed except the strut one, which is now back to OEM position, there was a problem with a prototype on a car that didnt have enough adjustability in the the coilover length, the car was slammed, even tho the difference in height was only 22.5mm. The car was using helper springs which were the root of the problem.

[TheRealSy90]

Has anybody raised their differential farther up in the chassis than the subframe risers allow, i'm tired of blowing out axles due to ride height, but I don't want to raise my car either. I'm thinking of chopping the forward mounts up higher and most likely mounting the diff up as high as physically possible. I blew three axles this weekend just trying to get to a drift event and still didn't get to drift. This is WITH 20mm axle spacers. The axles just can't take the articulation of tucking rim on 17's...

[ka-titties]

lol wow. after the second, a smarter person would have raised the car.

[PoorMans180SX]

Originally Posted by TheRealSy90

Has anybody raised their differential farther up in the chassis than the subframe risers allow, i'm tired of blowing out axles due to ride height, but I don't want to raise my car either. I'm thinking of chopping the forward mounts up higher and most likely mounting the diff up as high as physically possible. I blew three axles this weekend just trying to get to a drift event and still didn't get to drift. This is WITH 20mm axle spacers. The axles just can't take the articulation of tucking rim on 17's...

You could do that, but it might be easier to just raise the entire subframe up farther, chopping the bushing mounts down a bit. It would also be more advantageous from a suspension performance standpoint.

[yomisiu]

Originally Posted by TheRealSy90

Has anybody raised their differential farther up in the chassis than the subframe risers allow, i'm tired of blowing out axles due to ride height, but I don't want to raise my car either. I'm thinking of chopping the forward mounts up higher and most likely mounting the diff up as high as physically possible. I blew three axles this weekend just trying to get to a drift event and still didn't get to drift. This is WITH 20mm axle spacers. The axles just can't take the articulation of tucking rim on 17's...

that makes me second guess spending $100 on spacers. i would also like to know if there's an ultimate solution for low cars.

[az_240]

Originally Posted by ka-titties

lol wow. after the second, a smarter person would have raised the car.

man, fuck dat tho.

Originally Posted by TheRealSy90

Has anybody raised their differential farther up in the chassis than the subframe risers allow, i'm tired of blowing out axles due to ride height, but I don't want to raise my car either. I'm thinking of chopping the forward mounts up higher and most likely mounting the diff up as high as physically possible. I blew three axles this weekend just trying to get to a drift event and still didn't get to drift. This is WITH 20mm axle spacers. The axles just can't take the articulation of tucking rim on 17's...

Try out the Rzeppa (j30/z32) axles discussed earlier and let us know how that goes... Other solution would be to try chopping the subframe mounts a bit.