FWIW you can still get the J&M mounts for about the same price as the Founders pieces anyway.
http://www.coloradospeed.com/hotpart...d-p-23153.html
Got mine from there. No idea how long the sale lasts though.

I still wonder why Founders' lists their weight for their mounts on their site as higher than what my J&M's registered. Maybe that's the shipping weight? Either way I'd like to see them side by side or get some confirmation from the manufacturer(s) as to what the differences are, if there are any other than a sticker and a warranty.

 

Yes for sure. It is always best just to tell the truth.

Also, J&M has been around longer than Founders. Look up info on this site, the two companies are owned by the same guy. It is right there on the state listings.

 

This is better than a soap opera.

 

Kets not forget the post is about Umi, They have been quiet.

I think the J&M bearings so far have been decent quality (what ever they are) on the few cars I know of personally. However, it that is the bearing, then just like the other products that used the COM12T's and also munerous products that have used the QA1 rodeneds that most seem to never have troubles with- I will uspect that those bearings in the J&M bearings would be wiped out in my car very quickly like I have been mostly the ponly person to abuse them to that level with my settings and driving. Not a boast- just plain hard facts. Val's car has the J&M units and they have healed up great for him, I have adjusted them into different alignment specs many times on his car.

It would appear the bullet proof strut mount is still Steve Spohn. You never hear complaints or breakage for his- at least I never had. His are the original steeel versions of the prototype Hunter units. I still think Hunter's were the originals after all this becasue even though Hotparts claims 1990, I have yet to see any evidence I inquired about of theirs - and I do recall the product they made in 2004 (the design prior to this one) sucked becuase of lack of ride height clearance

 

If the bearings are from the US F&K and I think they are at this point. According to their catalog the COM12 bearings are rated at 31,920 raidal load. The FKS and FXSSX are rated at 78,000. That makes them 2 times plus as strong if they are using them.

About 3/4 down the page: http://www.fkrodends.com/Downloads/2...%20low-res.pdf

With that said if the COM is softer metal that is not always a bad thing. It will not crack as easy if that was the problem you had.



I looked all over spohn.com and could not find strut mounts for our cars? Where can I see them for sale? They would jump to the top of my list if I could find them. If for no other reason shady things in the other camp.



Also I don't think the Founders or J&M are bad parts just the same. I have seen nothing about a fail from them unless I missed it. They just seem to be a shady about the way they market them.

Heck, I am still waiting on UMI to confirm their bearings are pressed in. LOL They never did. If they are and this was a bad part.....


.

 

I checked out my UMI plates yesterday. The bearings are definitely pressed in. The part number on the bearing is FKS12T.

 

Agreed FK USA.

Two things on the load rating. First the listed load rating is radial load, which is the strong direction for sphereical bearings. We are primarily loading them in thrust, in which no spec is given.

Second, there is no standardized rating method for the load ratings. I would put little stock in the given values.

 

Ahem.

http://www.spohn.net/shop/1982-1992-...ut-Mounts.html

JamesC

 

I checked the UMI mounts I have and the bearings are pressed in.

I didn't see any mention of it, but has the OP contacted UMI directly (phone cal) about this problem?

 

Odd, I could not find them. LOL

Anyway they are not caster adjustable? What am I missing? Seems like if you actually lower your car you may not be able to get your numbers correct.

I know I am getting way off topic but I have to know.

.

 

Boy, I bet everyone who paid more for the J&M name feels like they got duped now.

 

We press the bearings in. Then back them up with the snap ring.

The OP has contacted us directly and we are taking care of it. Taking care of it includes satisfying the customer, reviewing our design parameters, etc.

ramey

 

Ramey,

Thank you for the information. In this case it looks like a qc issue (all companies have them) and not a design issue. Thank you for clarifying. My beef was with the fact that it wasn't a press fit.

John

 

Caster adjustment is built into the uni-body, not the strut mount. The holes for the strut mount in the body are slotted fore & aft.

RBob.

 

That explains a lot. Thanks. Have not actually had one off yet.

Now why do the other brands have extra on their mounts?

Sorry for the simple questions just trying to learn.

.

 

I have the UMI plates which have the added caster adjustments. I have my caster adjusted full forward on both the plates and the body. This is because I have the Spohn K-member and A-arms... and my front tires are still too far back in the wheelwells.

 

It gives you the option to adjust caster without disturbing the camber. Not a hug deal, but nice to have.

 

Caster will not significantly change the position of the wheel in the wheel well. You are likely causing harm with the caster maxed out in the wrong direction.

 

Thanks.

 

I'm aware that my full forward caster is not ideal, but neither is my front tires rubbing all the time.

 

That was going to be the next issue I was going to address- so let me put it my way:

How can a $17 FK bearing have a 78,000 load rating, yet a $60 Aurora high end PRN12 bearing have a 46,000 load rating. Especially when a Aurora Com12 has the same 31,000 rating as a QA1 COM12, etc and all of those are around the $15-20 range. Doesn;t make sense.

Also, the load on these bearings is Axial, not radial. Those figures are alot lower. If I recall my Axial (sideways) ratting where womething like 14,000 when the COM12's from all the companies were something like 6,900.

I am sure UMI is taking car of the client, but UMI, I would highly recommend you go to a machined pocket rather than a straight through bore with snaprings on both sides. One little problem like this one could be detrimental if it happens at the wrong time. This guy got lucky it did not happen on the road and that wheel assembly went astry at speed.

Dean.

ps- I still love the separate additional caster design of the J&M setup only becase it make my job easier setting alignments using those mounts, but the job can still be done with the regular type like Spohn's units.

The new design of an incorporated strut mount/STB I am making on Val's car makes it sdo he will no longer have to worry about alignment struggles getting the caster right but camber wrng and vica versa when you try and bump the strutmounts with a rubber mallet and such setting alignements. The incorporated design will attach to a unit body like Spohns and wil be manipulated into position on one side at a time by simply leaving the other side licked down to the tower, and then pushing and pulling the opposite strut mount Via the STB link and the firewall link. OOnce its dialed into position exactly in X & Y positions, you then lock down tht strut mount on the right- then lossen the left side and do it again- once finished and both are locked down. you then snug a little preload intot he 3 pt braces and lock them down in length and you are done. He will no longer have a need for that additional caster adjustment for making adjustment a little easier.

 

UMI only has a snap ring on the bottom. The top is retained by a machined lip...plus the press fit.

 

Well that was stupid. lets weld it together so the cup is down and the part has a potential to kill someone- real genious.

 

You know- the more I read and look closer at these pics people have posted, the more I am realizing these designs on both UMI and J&M are just completely dangerous. It doesn't look like from post#3 that even J&M have any kind of top retaining clip and that the top is merely being held by pressift and glue/ or just press fit alone?

I have never owned one from either of these companies. I have, like stated already, set the J&M ones in alignment many times BUT to be honest with everyone I never even looked at the bearing retention becasue I just assumed they were all like the HMS (Hunter) units and the SPohn units. Guess not.

I this point, I want to RETRACT any endorsement I have had towards even the J&M (which apeears also to be one in the same with Founders) UNTIL I see some kind of prrof that the bottom is soild (no way to slip through even if it's pressed in, and the top is retained by a clip.- I personally do not give a **** about this press fit becasue dampering forces cycling against it can press it right the f%ck out- just plain friking idiotic engineering. So until "I" personally see a design that has a bearing pocket that has built in safety like Spohn, then Spohn is it PERIOD.

SPohn's bearings can be replaced anytime if needed, Spohn's are STEEL, Spohns have top machined cups so a bearing is NOT held in on the bottom by a clip or spiral lock (un-friking-believable) so Spohn is the solid and safe strut mount- the ONLY one.

You people that disagree with this are low on the food chain and relying on the safety of a press fit vbearing to hold you front suspension together. just plain dumb. I would take this crap off my car in a heart beat.

I do not see ANY kind of retention on the top of this mount. I see a bottom groove for a snap ring, but no top lip or no snap ring- this is crazy.

 

As stated earlier our bearings are pressed in from the bottom to a solid machined lip on the top side. We machine our bearing cups to a very high precision of + or - .0002". I'm not going to tell you the size as it is a trade secret. We press the bearing in to a machined lip using a anaerobic sleeve retaining compound which has a typical shear strength rating of 3,900 psi. If you run the calculations on the the retaining compound alone is it puts the shear strength of the compound at aprox 11,000 pounds of force to shear the compound. Once the bearings are press in the machined shoulder on the top side we then back it up on the bottom side with a spiral lock. Before you start making slanderous statements I would suggest you get ALL your facts.

 

I have my facts straight- If they go together from the bottom, then they can come apart from the bottom. Its a stupid and unecessary design. It can be done the same way from the top where it would NEVER have the ability to unclip and unglue regardless of the perfect labor senerio.

One has just come apart that way- so my statement is not slanderous. I also would have probably never know they were built this way until this just happened to the OP with his UMI unit built in the same format so to speak. The original design concept Spohn is using will never allow this to happen...period.

 

So your saying there is more downward force? Let's put a 1000lb spring on the front end of the car. With the location of the spring on the lower control arm it would make the wheel rate about 500-600 lbs per inch. The max load possible on the downward side is going to be your wheel rate not your spring rate. On the (compression) upward movement you have impact loads which will exceed any downward load your spring can put on the bearing. Let's say it impacts and compresses the suspension 3 inches (that's a lot of travel) with a wheel rate of say 500 lbs that puts the load through the strut aprox. 1500 pounds. As you can see compression will load the bearing more than jounce. Bottom line if you aren't running a coil over that is mounted to the bearing itself you are way under the any load with any safety factor in either direction. We will always load these from the bottom as it is the smarter way to make them especially when most of our customers end up using coil-over kits (mostly on the mustangs). Please remember these are rough numbers and it also doesn't take into account the amount of load the shocks reduce by doing what they are supposed to do (dampen load).

Not to defend UMI but the reason that bearing came out is the customer was trying to impact the strut on with the dust cover in place. He basically pressed the bearing out when the dust cover came in contact with the bearing housing and he continued to use the impact gun. The only thing that would have saved that is a tighter press fit with some sort of sleeve retaining compound and I doubt that would have helped once he exceeded 5 tons. If it did help and he continued to impact on the bearing the ball would have exceeded the axial load capacity on ultimately pulled out of the race. I'm not sure of the what UMI bearings use but our bearings are rated at 78,000 psi from FK Rod ends which based on the industry standard of axial loading of spherical bearings is 15% would put that at about 11,700 pounds of force.

 

You are wrong in several ways- you just do not see it. In doing so, you are debating someone with vast knowledge and you will only make yourself look bad. ...So with that said, let's continue this debate.

Ill start with one main point- I will not get to how wrong your chassis dynamics load is other than briefly say the load is only shock damper force and basically nothing to do with spring load other than rebound force of higher rate springs pressing harder on the bottom side rebound damper. You have high piston speed and low piston speed. High piston speed generally "bleed off" so your theroey of hitting things on the upstroke is wrong. compression force dampering is less than rebound force ddampering on a normal street strut and especially on a performance or racing strut.

Now to that main point-

You seem to want to claim all these load values on your press fit and glued beaing and how the load is far less then what it ever could handle. So thus it will not move up or down....Am I right? yes so far from what you are saying.....So lets continue.....If the bearing is in there so well and you do not have to worry about it moving once its been assembled, AND since it obviously has to be assembled from inserting it into one side of the mount-THENNNNNNNNNNN, why are you putting it up through the bottom when it can stay in the same position if you simply flipped everything over- that way you would have the "ADDED INSURANCE" quote unquote that the bearing could never press, falll, be impacted etc etc etc out the bottom of the mount ever to avoid even .0001% of it ever risking the wheel assembly from falling out of sequence on the freeway, street, road, parkinglot, garage floor etc, etc, etc.

You are blind in your response. Do yourself a favor. Get off the keyboard and go figure a way to revesre the process of how you insert bearings into the bottom and figure out how to do it from the top where it can never come out of there and kill someone.

Go do it, and stop arguing nonsense because if you know anything about my reputation and experience I will expose every little fact about this. This is a public tech forum so that is what we do her is discuss chassis issues, not sell parts.

Dean

 

With a coil over kit you would want it in the bottom not top just like its made now.

I am still in the air with the load side with just the strut. I think it only makes sense to be on the bottom (just like it is now) but I got this thread locked last time I tried to debate it so I will bow out.

Edit. To fix a typo

 

How is the stock assemblies assembled?

 

This is exactly the problem. Most people do not understand how things are loaded. you are assuming becasue the weight of the car sits on them that the load is on the bottom pushing up against them- you are wrong.

Not even with a coilover is the load pushing against the bearing. Why? becasue a coilover on these cars is NOT a true coilover. The top of the coil rest against the under side of the metal fabricated strut assembly. The spring load does NOT touch to bearing. The only axial forces against the bearing are from the shock damper settings. The radial load (sideways load) is what is extreme due to spindle leverage force of braking and turning.

So lets look at a typical strut damper setting. Lets take QA1 for example with a typical circletrack shock. The settings run 1-12 in resistance force. 1 being less resistance damper, 12 being full resistance damper- these are axial loads on the bearing. A typical front shock or strut on a car of this style are about 2 in compression and about 7 in rebound. A performance strut will be more like 4 in cmpression and 10 in rebound.

Johnny- I believe the stock strut mount assembly is rubber and metal grommet that is sammiched (lol) between to metal sections spot welded together.

Anyone want to better understand shock vs strut? A shock only deals with dampering, whereas a strut is a damper that acts as a suspension location device (an upper arm so to speak. This is why there is alot of sideway load on the bearing (radial load), but the only axial load (up and down load) on the bearing is that of the damper force. If you want to understand better how the shock and the spring are separate and which takes the load of the chassis? then simply look at the back of the car- heck, remove the rear shock but leave the spring- then go drive it slowly around the block and see how it actas undampered. Yes it will keep bouncing because there is not rebound damper to slow the recoil of the spring every time it hits a bump. Since the spring is hard to compress yet easy to recoil back to didtance. The compression side of the shock is in direct proportion to the spring compression rate- basically to give an example when you change individual wheel srpring rates this is what happens:
Lets take a car with an effective rate of lets say 800lb spring- and that car has a 90* effective damper angle so it runs lets say a 4 in compression valving and a 9 in rebound valving. You are getting 2.5* body roll into a corner set of the chassis. THe next day you change to grippier tires and with the same setup you are now getting more speed through the corner (and thus more roll) your chassis is not rolling over the articulation perameters so you need to increase coilsprng rate from 800 to 850. You will then need to revalve the shock. thius generally means a LOWERING of compression valing from 4 to 3, and a slight raise in recoil/rebound valving since the higher rate will want to recoil the chassis(and hence the shock) quicker due to the greater force it releases whent he coil builds energy in compression in that 2.5" body roll in mid corner set.

Now you get a better idea how damper forces work. The AXIAL load on the bearing is pretty much only damper forces.

When the compression force is against the bearing it is in axail force against the bottom. When the strut is in rebound force, it is in axial load against the top- which wants to push it out the bottom of the strut mount........and remember people, the bearing comes out of the bottom while you are driving and your radial force of the strut has absolutely nothing but thin air to hold against it and you crash. I want my bearing going in from the top.

Here is a coilover assembly you can study. The spring does not rest against the bearing, it rests agaisn the torringtom thrust washers that rest against the underside of the fabricated strut metal. The secondary large underplate keeps the spring load from pushing the entire strut mount through- it has nothing to do with the strut shaft against the bearing, absolutely nothing- they are separate.
http://www.spohn.net/shop/1982-1992-...-Firebird.html

 

Final.. I understand what your saying. LOL Call me hard headed.

I have never seen one of our cars with a coil over so I did not know it was different than a normal one.

Also I believe the stock one is sandwiched.

 

OK, Here is an idea (sorry for the quick and crude drawings) that could solve this entire debate (or a lot of it). What if below the bearing cup there was another plate sandwiched between the bearing cup and the lower plate of the mount. This would be a failsafe plate (red part in the drawings) if the bearing came lose and the snap ring failed this lower plate would prevent the bearing from exiting the mount from below (see top picture).

Now even better, with some precision the lower plate could also replace the snap ring (middle picture) and be a failsafe and a retainer.

The lower plate would be need to be an exact fit that had the same ID hole size as the lip at the top of the bearing cup. It would move with the cup and be bolted between the cup and the lower plate.

To replace the bearing just unbolt everything and press it out from the top.

Before putting into production, PM me....

 

Second drawing, in this one the bearing cup mounts from underneath.

Now the red plate could be the one with the threads for the bolts to screw into OR it could have studs mounted and nuts on the top.

 

It is pretty much alot like what I was looking to do to my aluminum HMS units when the snap-ring failed- but I did not have access to a milling machine at the time. I wanted to mill off the top all the way down to the retainer ring groove and then plate the top with a metal plate to hold the bearing in placed sammiched together (yes I know it sandwiched- Larry the Cable Guy still makes me laugh)

 

I think I would probably thread the cup and screw in a hollow plug. That way there is no slack between the bearing and the retainer. Either way would work of course. Your way is cheaper and easier though.

John

 

Great idea, if nothing else, someone could make a plate like you show to add as a catch in the event of failure.

 

It could be an easy add to the current designs but the DIYer would have to be careful that the hole is small enough to catch the bearing but large enough to not interfere with any of the mounting. Should nto be too hard.

Personally I think it would be better if the manufactures got on board and did it for the no snap-ring required option (plate is the retainer).

 

Wouldn't a plate below interfere with the adjustment? Because it would be stationary, but the mounts are adjustable up top. If it was large enough to have movement in all directions, it would by nature also be too big to catch anything.

 

It needs to move with the mount (not stationary).

 

You guys are trying to re-engineer something that doesn't need it. I can't speak for how much press fit UMI uses and I really don't care. The reason the one the thread starter had a problem regardless of press fit is he was trying to install them with the dust cover on and essentially pressed the bearing out with the force of continual impact with the impact gun. He basically made a press using the dust shield as the base of the press and when he continued to force the nut down something had to give. It was going to be the bearing ball, the press fit, or a combination of both press fit and retaining ring.

Now lets look at why your aluminum piece failed since you keep comparing our unit to a aluminum piece. Your aluminum piece I would imagine was made from 6061 T6511 tubing and solid stock. The solid stock was machined to capture the bearing using a retaining ring of some sort. All that is fine as long as HMS machined the bearing cup to the proper press fit tolerance for aluminum and not steel. Since you are focusing on the retaining ring as a faulty area in design we will focus on that. Aluminum in the 6061-T6511 state has a yield strength of around 35,000 psi. Aluminum in the 6061-T0 state has a yield strength of around 8,000 psi. After looking at the HMS old units it looks like they machined a bearing cup and then tig welded it to a upright tube. Once you weld on 6061-T6 you need to re-heat treat back to the T6 temper. Welding on the aluminum anneals it to close to the T0 temper if not the T0 temper. The formula for the ring groove (not the ring) is GS=BDxGDxYSxPI

GS = Groove Strength
BD = Diameter of Bore
GD = Grove Dept
YS = Yield Stength of Material
PI = 3.14

If you want a safety factor you would divide all that by your safety factor.

Basically if you plug in the numbers based on our spiral lock grove and the aluminum camber plate you had after welding your groove strength is only 938 lb assuming they didn't heat treat after welding. If they did heat treat the part after welding back to a T6 temper (which I highly doubt) the groove strength to collapse the groove landing is 4,105. Now we don't use aluminum for our bearing mounts. Our bearing cups are machined from 1026 DOM tubing. I just looked at the last certificates and they came in with a yield strength of 94,500 psi. Based on that yield strength our ring landing for our current production will support 11,090 pounds of force. Now keep in mind that each and every batch of material comes in different so we have to design our parts based on the guaranteed minimum yield strength which for 1026 is 65,000 psi. That makes the minimum for a ring landing strength of 7,628 which far exceeds any loads you will ever see on the front ends of these cars even when using coil-overs mounted directly on the spherical bearing.

 

I am sure the flaming is coming when other read this....

My question is, if what you say is all said and done, why would anyone need a lip at the top of the bearing mount and why would anyone need a c-clip at the bottom of the nearing mount?

What we are offering is some real world knowledge and some food for thought about a maybe better, maybe worse solution. Maybe we are fullofshit, maybe not. But if we are fullofshit then I expect our ideas to not see the light of day....

 

It is called robust design. This covers all gambits from:

design for manufacturing
cost
ease of use
fail safe

I can see a few reasons for the machined lip in the cup.

1. Ease of installation on the bearing. With a hard stop its a piece of cake to know when you have pressed the bearing in far enough. This is common for almost any press fit.

2. Fail safe design. If the press fit fails, the lip will prevent the bearing from moving in the lip direction.

I can see a few reasons for the spiral lock as well

1. Fail safe design. If the press fit fails, the lock will prevent the bearing from moving in the lock direction.

2. Ease of installation, simple machined groove and lock.

3. Cost, spiral locks are inexpensive (and light weight).

You say why bother with the safety features if the press fit is designed to hold it. To that I simply reply with a series of questions.

Why does you master cylinder have two separate tanks and complete independent systems?

Why does your car have a vacuum reservoir?

Why does your car have an e-brake?

Why do aircraft have 4 separate hydraulic systems?

Why do commercial aircraft have minimum 2 engines

Why do your steering connections have castle nuts and cotter pins?

The answer to all of these is of course redundancy. One of the cores of robust design is how the system deals with failures.

It seems to me J&M has handled this just fine. I think this whole discussion started with wondering whether UMI and the others press in their bearings. The answer seems to be yes, and J&M at least has proven an understanding of how to design a press fit connection.

John

 

I think you have no idea that billet aluminum machined cap was 2 inches thick. it also failed on top side with the lesser load (the side that also is far away from the TIG weld). The bottom side oif my mount saw about 3x the load- the solid machined cup side. Gawd forbid the snapring were on the bottom of my units like yours.

 

I baically stated the same thing is slightly different wording, I fully agree.

What hotparts has failed to address is the issue of contamination and corrosion since both the snap ring and the bearing is exposed to the grim, salt and all other elements of tire to road contacts. That bearing is exposed. The top mount bearing is not becasue the ID of the strut mount is barely large enough for the strut shaft to go through.

 

I have still not read anything about one failing.

.

 

Everyone can take a closer look at my old HMS mounts. You can clearly see a lubrication drip trail coming out of the tight tolerance ID where the strut shaft goes up through. it is large enough for shaft articulation but that is it. You are looking at the bottom of a 2" billet cap. In other words the bearing is a full inch up inside the bottom of this before the bearing weidth starts. The bearing is another 3/4" thick, and then there is the 1/4" of material thickness left up top for the snapring and landing surface thickness. It would be very hard pressed for any contaminents to get up inside this mount design to ward off lube protection of the surfaces for corrosion and function. The bottom mount style has a much larger opening becasue the entire bearing lip and snap ring need to fit up inside underneath there. It is exposed. How long you think that is going to last? Time will tell. I also live in sunny So Calif., land of no salt roads.

Every time Hotparts wants to add to this debate, I will keep adding info against it. Lets see how far he wants to take this exposure.

 

All of this is exposed right to the underneath fender elements.

 

That is the nature of the design. Your mounts can be like that because they don't have the independent caster adjustment.

With all do respect, I don't understand dragging them through the mud over a pretty low risk corrosion issue. I totally get it and agree with questioning potential safety issues, but not this. Don't like the design? then don't buy the product.

With proper material selection and coatings there is limited risk of corrosion of the bearing.

John

 

I may be retarded, but is there enough suspension travel during normal driving for the bearing to come all the way out through the bottom? Having a hard time picturing this... I've seen many struts shoot through the hood due to worn out mounts on cars at work and I understand the suspension compression/ rebound thing but I don't see how the failure in question would happen.