[Pparana]

which I responded:

"Ok thanks, on closer inspection the inside of the camber plate where it meets the perch is exactly on the seam of the bearing. I think if that inside was longer, it would locate, or if the bearings were completely sealed it may work.

Will probably just end up selling them. I do not think they will hold up. I will let the guys on the forums know they are not for lowered cars, lots of people wanted to know how the new design would work. I would assume this would span the whole realm of f series sedans. I had hope...."

[Pparana]

KMAK plates:

Adjustable plate (camber and caster) sandwich design. Bearing carrier is located on a threaded aluminum hat that is pressed into the center of the camber plate. A polyurethane bushing is used to isolate the energy which is pressed into the aluminum hat. The bearing itself is all metal, needle bearing with a dia. Of 16mm (bearing itself) This is located on the perch which had a dia. Of 54 mm and a thickness of 3mm. This gives a total dia of 87mm. The bearing is located at the bottom of the hat with an additional 13mm of extension beyond horizontally.

Kmac kit comes with various spring perches for coil overs or oe dia. Shocks, kit also comes with bump stops, I would not use the bump stops as they are poly and will give a pretty harsh ride. The oe Dia shock mount is constructed of a urethane bushing pressed on an aluminum hat. The urethane bushing is tapered vertically like the oem perch , a bit more aggressively (20 mm of taper, 81mm to 101mm). The aluminum perch has an outside diameter of 128mm the oe spring perch is tapered on the backside to allow it to self-locate, all parts are aluminum so there is no chance of binding or tearing. Bearing housing is threaded to shaft, so it can not be unintentionally dislodged.

Pros
Plate is very robust, seems to meet or exceed the oem specs in all cases. The sandwich design allows for the forces to have a much larger surface area to disperse energy over, more similar to the oe perch.

Camber and caster adjustment, with infinite finite settings, Very beneficial for corner balancing.

All the bushings and bearings can be replaced or rebuilt.

Cons:

Bearing is not sealed, so will require some upkeep and not ideal for winter climates.

The design of the sandwich is delicate, if over torqued at all the plates will be distorted and not function properly. One must take care in making adjustments and a inch pound torque wrench is recommended.

These are isolated but will transmit more noise than some other designs. KMAK also makes a race version with no isolation and a street version, but I have not seen any vendors stocking those plates stateside.

On our cars, on the first set the strut bar locator bolts were mis pressed. I have not tested the second set but I will let you know if that problem persists.

My Thoughts:

My experience with these plates has been good until they were over tightened. They never moved, had some low speed noise but not much and I ran them for 5000 miles and prob. 12 track events.

If you go to an alignment shop you have to be vigilant about the torque specs. A few ft pds will ruin them. I ended up getting the equipment to do alignments myself so this is not an issue for me. I think for track use and dd this is a pretty acceptable combination. I ran on KW springs and Dinan with no problems. Prob 2000 track miles of which 500 were on dinans and m3 lcas.

I had this set overnighted so I can get back on the road and hopefully the track this weekend, For my application they are a good fit.

[GCSystems]

Originally Posted by Pparana

I was not really planning on getting into the customer service on this but seems you guys want to open that can of worms its off to the races.

Pparana,

You're more than welcome to get into customer service. You order was invoiced on Monday, 8/24(order was placed on our website over the weekend), and shipped out Monday, 8/24 with a UPS tracking number e-mailed to you. The camber plates were shipped from CA and delivered in FL on Wednesday, 8/26. I had also replied back to any pre and post sale orders within 1-2 hours of your e-mail being received.

On Monday 9/1 you had e-mailed me saying your "the perch gets stuck on the spring. I tried adding some idolators but had the same issue".

I had called you no later than 20 minutes after receiving the e-mail. Once you had described what happened I asked if you had installed the OE spring pad. You're answer was NO. You said you had torn them while doing a previous install and did not install them while installing out camber plates. Again, the pads have a stepped section to locate the spring correctly and distribute the spring load evenly on the upper hat.

I then offered to send you 2 new bearings free of charge, and you were going to "order some new boots and we can see what happens". We have brand new OE spring pads here on the shelf, if they tore with the plates installed, don't you think I would have offered to send you some as well?

I would say our customer service with you has been above average, and I have no reason to lie about our conversation.

Trevor

[Pparana]

Originally Posted by GCSystems

Pparana,

You're more than welcome to get into customer service. You order was invoiced on Monday, 8/24(order was placed on our website over the weekend), and shipped out Monday, 8/24 with a UPS tracking number e-mailed to you. The camber plates were shipped from CA and delivered in FL on Wednesday, 8/26. I had also replied back to any pre and post sale orders within 1-2 hours of your e-mail being received.

On Monday 9/1 you had e-mailed me saying your "the perch gets stuck on the spring. I tried adding some idolators but had the same issue".

I had called you no later than 20 minutes after receiving the e-mail. Once you had described what happened I asked if you had installed the OE spring pad. You're answer was NO. You said you had torn them while doing a previous install and did not install them while installing out camber plates. Again, the pads have a stepped section to locate the spring correctly and distribute the spring load evenly on the upper hat.

I then offered to send you 2 new bearings free of charge, and you were going to "order some new boots and we can see what happens". We have brand new OE spring pads here on the shelf, if they tore with the plates installed, don't you think I would have offered to send you some as well?

I would say our customer service with you has been above average, and I have no reason to lie about our conversation.

Trevor

"Then don't complain to me, complain to BMW who uses that bearing on every
M5 and M6.

We buy thousands per year, and only have a problem if the bearings have
been disassembled by someone, then reassembled without lining up the seal edges. This
is quite obviously what has happened with your car."

Thats from Jay, Top notch my friend...

[Pparana]

Originally Posted by JM3

Quoted for posterity:





The part that locates the bearing extends halfway because each side of the bearing extends halfway!

The seam is where the two halves of the bearing must rotate!

The support has to end there, just like stock BMW.


JM3

I am assuming you are Jay from ground control correct?

Jay,

not quite, stock BMW bearing carrier sits flush with the plate, only the top rotates. There vertical aluminum extends to the top.

See photos below.

[Pparana]

Originally Posted by JM3

No one at Ground Control ever said that.

We say these are for use with stock style springs (which are bent). Many aftermarket springs are not bent , because the bent springs are more expensive to make.

The geometry of the front strut / inner fender interface of the F22 is designed to use a bent spring, and reverting to a straight spring causes problems with or without GC parts.


Pic:

The only spring I tested on was Dinan, which I happen to have photos of dinan stock and hr, since I own a pair of all three. They are all bent and have similar design. I would think none of these would have adverse effects.

dinan and bmw springs share the same dia. (14mm) at top and have an identical bend radius, dinan achieves there slightly higher spring rate and lowering effect by winding the coils slightly closer (about 30%). Other than that they are the same design.

[Pparana]

Also I have included some photos of the shock boot, while it bound and got ripped, you can see it only changes the inside dia by about 1.5-1.75 mm.

I believe this is used more for sound damping and to protect the shock, as far as the pads on the side, it seems more to me they are to keep the dust boot from falling down the shock. I could be wrong and your plates may be sensitive to under 2 mm of clearance. I did not design or validate them.

[Pparana]

sorry a couple of images were taken with the spring upside down in last post. Here are some corrected versions.

[JM3]

Your pictures are not of the BMW bearing that GC buys from BMW, and are not the bearing you are talking about.

Again, with an open-minded observation of the parts, the flange you indicate is to externally support the "Additional Shock Absorber" (click here for pic) as it bellows out during strut travel, and has nothing to do with the bearing.

Our company has assembled and tested these supplemental springs on a Roehrig shock dyno to see the movements and determine the spring rate. That is how I know why that flange is there.

Originally Posted by JM3

Originally Posted by JM3
Quoted for posterity:

Originally Posted by Pparana

Furthermore your spring perch gets located by a part of the plate that only extends half way down the bearing and end on the seam of the bearing case.


The part that locates the bearing extends halfway because each side of the bearing extends halfway!

The seam is where the two halves of the bearing must rotate!

The support has to end there, just like stock BMW.


JM3

Originally Posted by Pparana

I am assuming you are Jay from ground control correct?

Jay,

not quite, stock BMW bearing carrier sits flush with the plate, only the top rotates. There vertical aluminum extends to the top.

See photos below.

[JM3]

Originally Posted by Pparana

sorry a couple of images were taken with the spring upside down in last post. Here are some corrected versions.

This is the most common reason fro the upper perch to get ripped.

As I *gently* alluded to in an email to you on September 1st:

Originally Posted by email from GC to PP

In addition, the stock springs are very slightly different diameters top
and bottom, and Dinan (or any) springs could have been mislabeled as to
which end is up.

[Pparana]

Originally Posted by JM3

This is the most common reason fro the upper perch to get ripped.

As I *gently* alluded to in an email to you on September 1st:

Taking photos upside down? Thanks Ill keep an eye on that

[Pparana]

Full Disclosure. Ground control has stated that they do not want me posting about this on the internet. They will probably not refund my plates if I post. I really do not care if that is there position, as I do not think posting your experience or lack of and the design characteristics of a product should effect your warranty or return policy. If it does so be it. These forums are designed for people to share their experiences positions and thoughts. No one has to agree with anything I or anyone else is saying.

GC Design
Adjustable Plate with bearing and carrier. Bearing dia. of 86mm. Encased in a flat metal jacket with a thickness of 2.5 mil Adjustable plate does not span the diameter of the bearing horizontally or vertically (2.5-4 mil short vertical and horizontal across whole diameter)
Bearing position is designed in such a way that the only connection for the spring and the perch is the bearing.
Bearing carrier is located in an aluminum spring perch with an outside dia. of 90”. Perch not tapered horizontally, however does have a <1 mil convex arc over the vertical plane which has a dia. of 23 mm.

Pros:

Easy to adjust
They are pretty and have nice machining
Quiet, probably the quietest plates you can get
Pillow top bearing for strut to move, less stress on strut.

Cons:
Not designed for lowered cars, oe only (or maybe not GC?)
Bearing is not robust
Locating the bearing can lead to wear and failure
Bearing does not appear to be properly sized or located.

My Thoughts:

This is the second version of the plates for f series cars. There were some failures with the previous design. I have no knowledge of the construction or design of those plates. The plates in are close but not 100% ready. Obviously I did not get a chance to run them that long. I will make another entry with where they failed. A few more hours in the R&D oven should solve it.

[JM3]

Originally Posted by Pparana

sorry a couple of images were taken with the spring upside down in last post. Here are some corrected versions.

Originally Posted by Pparana

Taking photos upside down? Thanks Ill keep an eye on that

Which is it?

[JM3]

Originally Posted by Pparana

"Then don't complain to me, complain to BMW who uses that bearing on every
M5 and M6.

We buy thousands per year, and only have a problem if the bearings have
been disassembled by someone, then reassembled without lining up the seal edges. This
is quite obviously what has happened with your car."

Thats from Jay, Top notch my friend...

Lets just quote the whole conversation, with no editing:

Originally Posted by PP to GC email

Respectfully as a mechinical (sic) engineer for with a phd (sic) in theoretical and applied mechanics, those plates will fail at the bearing.

Originally Posted by reply from Jay

Then don't complain to me, complain to BMW who uses that bearing on every
M5 and M6.

We buy thousands per year, and only have a problem if the bearings have
been disassembled by someone, then reassembled without lining up the seal edges. This
is quite obviously what has happened with your car.

(As strongly evidenced by your picture showing the lip seals folded and unfolded inside and outside of each other within a small arc)

We will be happy to refund the price of the Camber / caster plates, and
I truly hope everything works out better for you.


You have made a veiled threat about posting "bad things" on the internet.
I would appreciate if you would not "seek revenge" like that. I would ask
that you just accept me at my word that these camber /caster plates DO
work, have been extensively tested, have been FEA'd, and that there is
some problem with your car and spring combination that makes it differ from OEM ( which is what all our testing has been done with).

[Pparana]

Originally Posted by JM3

Which is it?

its a joke.. lighten up guy!

[JM3]

PP observation of the OEM spring pads:

Originally Posted by Pparana

I believe this is used more for sound damping and to protect the shock, as far as the pads on the side, it seems more to me they are to keep the dust boot from falling down the shock. I could be wrong and your plates may be sensitive to under 2 mm of clearance. I did not design or validate them.

Ground Control observation of the spring pads, as quoted from an email:

Originally Posted by email from GC to PP 09/01/15

Also, in regards to the angle of the spring, the GC upper spring perch is specifically designed to use the OEM rubber upper spring perch which not
only correctly locates and centers the spring, but upon careful inspection,you will notice that is cleverly designed to allow the bent spring to
settle the load evenly onto the upper perch. Our company has never tested our parts without the stock (OEM) upper pad, but I do believe that using anything else would cause problems with the spring seating.

[Pparana]

I really do not like ripping into peoples designs, as there are not enough small aftermarket company's as is, its a tough business and very hard to test and make money. That being said the part has to function. I really do not want to get into there response, or combativeness, I think they have done a good job of that on there own.

Or it might be a better explanation that I just decided to destroy the bearing and make some long winded posts. I will leave it at that.....



Alright here is where this bearing failed on my application:


If you look at the photos you can see the bearing separated on the perch. It then rolled itself over on the metal bearing plate. This type of failure is due to the plate not supporting the whole bearing.

Also the plate is designed where the bearing has to pass the whole load via the case. Which is thin plastic which will heat up and deform. so there are a few faults here. Without a full and true horizontal support the bearing acts like a saucer, or spinning top that coupled with the thin plastic case allows for deformation. This causes the load to be deflected and not loaded evenly. Then the bearing is operating out of spec and fails.

On lowered cars the perch has a hard time locating itself on the shaft since there is only half a horizontal support. So if the perch moves it could scrape or bind the bearing case, which is not very strong. This could also lead to the failure by deforming or binding the case.

I do not know the load rating of this bearing. Jay and GC says it is from an m5 or m6? last applicable use I could find for this bearing was in the e38 series (7 series 95-01). Part # on bearing is: F-2198762

This design may function on a street car, but I can not see on a track car or anything with camber. I do not think under the most optimistic settings that bearing will last 15k.

The other issue on failure will be you probably wont notice it until it is catastrophic. Those parts could melt, heat up expand until they cant hold the force anymore. This would cause the spring load to unwind rapidly, possibly causing loss of control quite close to the previous failings.

Again if these were FEA validated properly I do not see the harm in sharing that data. I did ask if they ran any FEA simulations on there parts. I stated If he would provide the models I would keep them.

Jay says they do, but wont share the model. He says take his word for it.

No engineer can "look" at a part and say it will fail, that is the point of FEA DOE modeling.

Testing, validating is the hallmark of engineering,FEA DOE MODELING, prototyping, real product world application testing. In parts as critical as suspension one must not cut corners nor ignore real world failures.

That is why we wear the iron ring, I hope any engineer would take real world failure seriously when there is a potential to harm people and property. Such occurrences should not be casually dismissed. That is the point of this post.

[rwalker]

Originally Posted by Pparana

Taking photos upside down? Thanks Ill keep an eye on that

he means you installed the spring upside down

my shop did it wrong on one side, and sure enough that isolator was torn in a fashion identical to yours

[Pparana]

Originally Posted by rwalker

he means you installed the spring upside down

my shop did it wrong on one side, and sure enough that isolator was torn in a fashion identical to yours

yes I know what he meant. No they were not installed upside down. If your shop is installing upside down, you may want a new shop. Progressive springs are pretty easy to sort, esp. when they have writing on them. I do my own work (hobby).

In my case I verified with Dinan prior to install just to be sure since they are after market. The engineer in me always wants validation, so when instructions are lacking just send an email.

[rwalker]

Originally Posted by Pparana

yes I know what he meant. No they were not installed upside down. If your shop is installing upside down, you may want a new shop.

I've actually given up on shops, went through 3 before going DIY. Not going back.

[rwalker]

Originally Posted by Pparana

yes I know what he meant. No they were not installed upside down. Progressive springs are pretty easy to sort, esp. when they have writing on them. I do my own work (hobby).

What's your theory on why the perch isolator tore?

[Pparana]

Originally Posted by rwalker

What's your theory on why the perch isolator tore?

friction. Its just 1 mil rubber, I am sure most people on lowering springs will tear, wear them.