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

[scottie]

Originally Posted by Motary

Have you adjusted the lengths of the upper links yet? The bearing bolt pattern should be perpendicular with the ground

I did adjust the upper lengths. I began with OE lengths, then adjusted the camber, toe and traction rods accordingly. I supported the bottom of the LCAs to simulate the 90* static stance. Per GKtech's instructions, I adjusted the camber and toe rods for near 0*. I do not have a specific measuring device to I had to use tape and string as best I could. The ideal length for the traction rod on a S13 subframe is 212mm ~ 8.35" which is what I came out to be. All of these measurements will be checked once its under the chassis during final assembly.

[scottie]

Originally Posted by LuckyX2

Also, just curious, scottie, what diff/stubs are you using? I notice you're running the Z32TT/Q45 axle combo.

Q45 3.65 R200 Diff w/6 Bolt output shafts, 300ZX TT Driver/Q45 Passenger Axles. SPL solid diff mounts. Subframe is fully gusseted with GKTech's kit.

[LuckyX2]

So what's the Ackerman curve like on the new revision of the GKTech knuckles? It was posted for the billet Al ones, but I don't recall seeing anything for the steel.

Just wondering if I should get eccentric steering rack bushings or not, to put some more positive Ackerman back in (assuming the GKTech's are reducing it for drift applications)

[sr vegas 240]

I just purchased s13 gktech roll center correction kit shill haven't received it and now wondering should I have just gotten the their knuckles or pbm knuckle I paid 230 and for 200 more I could of had the knuckles. I know this is the cheaper way to go to correct roll center and it gives you up to 60 degree of lock. Am I missing anything by not getting the knuckles or will this do the trick?

[scottie]

Originally Posted by LuckyX2

So what's the Ackerman curve like on the new revision of the GKTech knuckles? It was posted for the billet Al ones, but I don't recall seeing anything for the steel.

Just wondering if I should get eccentric steering rack bushings or not, to put some more positive Ackerman back in (assuming the GKTech's are reducing it for drift applications)

I believe Greg has posted it on their Instagram account before. He touches on it under the description on their website.

I cannot recommend staying away from eccentric rack bushings enough. I know guys run them but any parts that doesn't allow the bolt to seat all the way on a steering rack mount makes me nervous. So much so I sold my PBM rack bushings for the offset ends from GKTech. Wisefab and other top end companies use this type of setup. Ultimately moving the actual mounts forward would be the best solution but not all competitive series will allow it. Plus you may not clear your oil pan depending on the motor you use.

[LuckyX2]

Originally Posted by scottie

I believe Greg has posted it on their Instagram account before. He touches on it under the description on their website.

I cannot recommend staying away from eccentric rack bushings enough. I know guys run them but any parts that doesn't allow the bolt to seat all the way on a steering rack mount makes me nervous. So much so I sold my PBM rack bushings for the offset ends from GKTech. Wisefab and other top end companies use this type of setup. Ultimately moving the actual mounts forward would be the best solution but not all competitive series will allow it. Plus you may not clear your oil pan depending on the motor you use.

There's zero mention (that I see) of Ackerman on GKTech's page for the front knuckles. As for Instagram, I'm not sure.

Do the offset tie rod spacers change Ackerman? I thought they just corrected overcentering and to affect Ackerman you have to actually move the pivot point of the tie rod which is at the rack.

[PoorMans180SX]

Originally Posted by LuckyX2

There's zero mention (that I see) of Ackerman on GKTech's page for the front knuckles. As for Instagram, I'm not sure.

Do the offset tie rod spacers change Ackerman? I thought they just corrected overcentering and to affect Ackerman you have to actually move the pivot point of the tie rod which is at the rack.

You change the ackerman curve of the steering when you add offset rack spacers or move the rack forward.

[scottie]

Originally Posted by LuckyX2

There's zero mention (that I see) of Ackerman on GKTech's page for the front knuckles. As for Instagram, I'm not sure.

Do the offset tie rod spacers change Ackerman? I thought they just corrected overcentering and to affect Ackerman you have to actually move the pivot point of the tie rod which is at the rack.

What PoorMans180SX just stated, both will affect Ackerman. My understanding from Greg is his latest knuckle can be used both Drifting and Circuit racing which leads me to believe it isn't designed for 0 Ackerman (both wheels turn same amount). Greg states his knuckles do not increase scrub radius. I wont know for sure until I install my entire setup and take measurements. Of course this gets further complicated when you introduce longer lower control arms, extended tie rods and no sway bars for further turn in.

[PoorMans180SX]

I know the new GK knucks have lower ackerman than driftworks geomasters.

[TheRealSy90]

I guess I could post this.

Rack moved forward on crossmember.
25mm extended flca and inside bushing replaced with heim joints and boxed.
Passenger Maverick rack extension, driver side PBM tie rod spacer, oem s13 inner/outer tie rods lifetime warranty.
VooDoo13 tension arms.
GKTech 40mm roll center knuckles.
17x10 -4 225/45.

On my Instagram @sylas_g there's video of lock-to-lock.

ImageUploadedByTapatalk1447464937.516089.jpg
ImageUploadedByTapatalk1447464954.263136.jpg




Sent from my iPhone using Tapatalk

[sr vegas 240]

Originally Posted by TheRealSy90

I guess I could post this.

Rack moved forward on crossmember.
25mm extended flca and inside bushing replaced with heim joints and boxed.
Passenger Maverick rack extension, driver side PBM tie rod spacer, oem s13 inner/outer tie rods lifetime warranty.
VooDoo13 tension arms.
GKTech 40mm roll center knuckles.
17x10 -4 225/45.

On my Instagram @sylas_g there's video of lock-to-lock.

Attachment 88814
Attachment 88815




Sent from my iPhone using Tapatalk

How do you like the roll correction kit I just got mine and can't decide if I should keep it or sell it and get some drop knuckles. I just got it in the mail today I might put them up for sale.

[derass]

Originally Posted by sr vegas 240

Am I missing anything by not getting the knuckles or will this do the trick?

The downside of these adapters is that they increase the scrub radius more than knuckles do (if at all).

Sy, are you rubbing anywhere? With my setup, I found wide wheels and big angle difficult to get right.

[TheRealSy90]

My setup doesn't rub anywhere no. For mine the increased scrub radius is the main thing that helps clear everything. Otherwise I'd be hitting the frame rails and sway bar.


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[sr vegas 240]

I will try to sell it and get the drop knuckles

[PoorMans180SX]

Originally Posted by sr vegas 240

I will try to sell it and get the drop knuckles

Why are you so concerned about the scrub radius? Buy wheels with a higher offset and boom you're back to the same scrub radius. It's not a big deal until you get an extremely positive one anyway.

[sr vegas 240]

Can't afford new wheels I have some enkei j 10 18x7.5 low offset they sit about 2 inch under the fenders.

[PoorMans180SX]

Originally Posted by sr vegas 240

Can't afford new wheels I have some enkei j 10 18x7.5 low offset they sit about 2 inch under the fenders.

Yeah, you'll be just fine.

[sr vegas 240]

Awesome I'll go and put them on. Main reason for getting them is I had bad wobble at full lock while drifting. My mods are touge factory inners phase 2 pillowball outters circuit sports offset rack spacers stance coilovers.

[PoorMans180SX]

Originally Posted by sr vegas 240

Awesome I'll go and put them on. Main reason for getting them is I had bad wobble at full lock while drifting. My mods are touge factory inners phase 2 pillowball outters circuit sports offset rack spacers stance coilovers.

Reduce your static caster a bit. Try 6 or 6.5*. Caster wobble + old rack can make the steering feel like that.

[sr vegas 240]

I'm not sure what my caster is I tried to match it to the stock tension rod lenght

[PoorMans180SX]

Get an alignment for sure, and stress that you want the caster set to 6*.

[a-s-silvia]

Sounds like a common problem the company doesn't care about, I don't know what they are using to machine the spindle but the tooling is not accurate at all. Having to modify something you paid good money for is BS in my book. No issues with Wisefab, PBM or TDP

Originally Posted by taeisbeast

Well, these arent ebay. thanks though.

Orange tree FLCA. I did notice the bolt seemed a little bent though.

Any thoughts on where I can source a replacement.

Thank you.

[PoorMans180SX]

Originally Posted by a-s-silvia

Sounds like a common problem the company doesn't care about, I don't know what they are using to machine the spindle but the tooling is not accurate at all. Having to modify something you paid good money for is BS in my book. No issues with Wisefab, PBM or TDP

I've seen a few issues with Parts Shop Max limit break stuff, but not the normal ones.

[GKTECH]

alternatively maybe it's just S13 vs S14 ball joint supplied with the LCA's? Either way it's not right and I wouldn't modify it before speaking to Orange Tree about it.

[jaysgottaredtop]

Or follow Def's guide to rebuild them with better hardware

http://www.nissanroadracing.com/showthread.php?t=1407

Also, holy hell, that write-up was posted 6 years ago today. Time is flying by.

[ka-titties]

damn. time does fly.

i followed that write-up for the LCA's i currently have on my car.

[2_Liter_Turbo]

Originally Posted by scottie

PSA: GKTech V2 Knuckles may need modifying to fit oem hubs. I am not sure if this is a common issue or not. After exchanging emails with Greg, the solution is to use sandpaper to slowly and carefully shave the spindle shaft. This was nerve racking to say the least as these are not cheap knuckles and one could ruin a pair quite easily if too much material is removed.

Below is what worked for me and may work for others who have similar issues.

These are brand new S14 hubs with extended studs. I test fitted these several times on the OEM spindle, noting how they glide onto the spindle shaft with minimal effort by hand. Greg stated I would have to press the hubs onto his spindles. I attempted this but ran into the same issue (I wasn't about to use the full power of my 12 Ton press). After feeling resistance, I stopped. I removed the hub with a pulley puller but was creating so much resistance I decided to separate the hub bearing to remove in 2 pieces. Using a little bit of heat, I got it off and decided the only solution was to shave the spindle shaft.



Mic' the OEM and GKTech back to back over several areas. For the most part the GKT shafts were uniform but did have a few high spots, most likely caused by the base metal being used.







It was decided to attack the issue two different ways. I used 600 Grit sandpaper, WD-40 and light pressure making sure to constantly rotate the knuckle to prevent flat spots on the Drivers Side spindle. My friend decided to file down just the high spots, leaving the majority untouched on the Passenger Side spindle. I am happy to say both techniques worked. This took a couple of hours as it is very important to take your time, measure and test fit as you go.



Both hubs now glide on the GKTech just as the OEM spindle. I hope this helps others who may have the same experience.

I had a different issue with mine. The hubs went on just fine... well at least on one side, I haven't tried the other side yet (New OEM S14 hubs as well). However, the shock mounting holes didn't line up so I had to use a die grinder to remove material in the knuckle to get them to fit. Wasn't super thrilled at having to that.

This is how much they were off on my coilover:


This is the OEM strut:


Here's the knuckle before I modified it:

[GKTECH]

Originally Posted by 2_Liter_Turbo

I had a different issue with mine. The hubs went on just fine... well at least on one side, I haven't tried the other side yet (New OEM S14 hubs as well). However, the shock mounting holes didn't line up so I had to use a die grinder to remove material in the knuckle to get them to fit. Wasn't super thrilled at having to that.

It would appear that your knuckles were from an early batch which we did have some issues with the jig, however this has now been resolved. Note that you could have returned them to be swapped over to a set that didn't have this issue.

Teething issues with a new design is certainly not an excuse but we do stand by our products 100% and if there is an issue we will fix it. Both myself, our engineer and Dan in the US warehouse all have S chassis' and run all our gear on our own cars so constant improvement to us is imperative.

[2_Liter_Turbo]

Originally Posted by GKTECH

It would appear that your knuckles were from an early batch which we did have some issues with the jig, however this has now been resolved. Note that you could have returned them to be swapped over to a set that didn't have this issue.

Teething issues with a new design is certainly not an excuse but we do stand by our products 100% and if there is an issue we will fix it. Both myself, our engineer and Dan in the US warehouse all have S chassis' and run all our gear on our own cars so constant improvement to us is imperative.

I totally understand the teething issues on a new design, I've been there, trust me, lol.

I was told to modify them by you guys though, and wasn't offered an exchange at the time. These don't work with my brake kit either, which is why I haven't fully used them yet (still sitting on my desk). I thought I saw somewhere that you guys were doing a V3 version that moved the brake caliper mounting points back to the factory-ish location, is this true? I would definitely be interested in an exchange for that!

[GKTECH]

We may have not had another set at the time as during the first few batches they were all sold out pre buy.

The V3 does rotate the caliper further around. Send me an email to [email protected] with the specifics on your setup and we'll see if they'll assist however either way swapping them over is no issue at all.

Regards,
Greg