so on my way to the AX saturday i noticed a "clunk" sound from the frontend, like i had lost something.
i had this happen before, bolt came lose on the swaybar droplink, so i thought that was it ...

when i get to the AX site and change tires, i see the droplink hanging all weird so i take a closer look and the lower hime joint has broken. the thread just snapped off the joint.
i then continue to change the tire on the other side and it's exactly the same!

both hime joints broke in the exact same location. that seems too odd to be coincidence.
i must have hit something *really* hard for that to happen, but i can't remember running over any bad potholes etc.

anyone else had problems before?
Andy

Didn't you weld on the u-tabs rotated 90 degrees from the stock orientation? (Stock = the bolts run fore-aft)

my rant on "everybody else's" 8mm-5/16" droplinks is on record here multiple times (with pictures).

you broke the Tarett 10mm joints!? zowie...

does this look like compressive fracture (are the droplink shafts bent?)

do have spacers on each side of the Heim joint to account for the misalignment and keep the joint centered in the shackle? if not, i can see that it could get cocked in there...

(and in focus, please!!)

Seriously, though--what do the drop-links look like now? Bent, as Rich asks? How do the actual breaks themselves look? Are there "broach marks" that look like ripples from one spot?

It's a good idea to talk to Tarrett on this one, see what they have to say.

--DD

QUOTE (ArtechnikA @ Jul 25 2005, 11:25 AM)

my rant on "everybody else's" 8mm-5/16" droplinks is on record here multiple times (with pictures). you broke the Tarett 10mm joints!? zowie...

Yea, doesn't Smart Racing use the smaller 8mm ones?
Andy, I have not broke those, but one of my drop links "slipped" out and stripped a bit, but it was fixable.

QUOTE (ChrisReale @ Jul 25 2005, 04:11 PM)

Yea, doesn't Smart Racing use the smaller 8mm ones?

yes. i have a Smart front bar.
it will be uprated for 10mm hardware before i put it on the car.
(i already bought a pair of Tarett adjustable droplinks.)
one of the Smart parts will need a small mod; it will IMO be worth it.

i understand the 8mm must be "adequate" or we'd be hearing of failures right and left, but i have already had one car destroyed by a drop link Heim joint failure, and i do not mind people pointing and laughing if i over-engineer this part :-)

Sor Ahndie,

Show us a picture of the break!

Might be able to determine what caused the failure by the shape of the break and where it started.

Ken putting on his Mechanical Engineer hat and looking around for his copy of fracture mechanics....

QUOTE (Dave_Darling @ Jul 25 2005, 12:38 PM)

(and in focus, please!!)

no camera until wednesday (shannon is on a biz trip in canada and she took the camera) ...
drop links don't seem to be bend ...

QUOTE

Didn't you weld on the u-tabs rotated 90 degrees from the stock orientation? (Stock = the bolts run fore-aft)

yes. and i did this so the himejoints wouldn't bind on the u-tabs!
the only time they would hit the u-tab is when the car is up on the lift, once on the ground it's perfectly center.

hmmmm, now you got me thinking ...

remember when i almost flipped the car over? the front wheel was completely unloaded, meaning the hime-joint must have hit the u-tab holding that wheel up in the air.
maybe that was too much ???

but both sides brake at the same time at the same location?
Andy

Ive heard the people at Tarett are very good and stand behind their products. You may try sending Ira an email with pics. Who knows, it may be a product flaw and he'll correct it

Hi Andy,
Was it the upper or lower rod ends? I’m guessing that it’s the lowers. Not sure if I agree with rotating the mounting tabs. Check to see if they got bent. Rotating them will probably cause binding when the car is jacket up and the front suspension drops. They may also bind when the suspension is compressed. Please PM me with pictures and your address, and I’ll send you new parts. Then we can figure out where the binding is coming from. I’ll also need to know which thread you need (right or left), and if you need new drop links too.

Thanks,
Ira

Ira's stuff rocks....

i snapped a Utab off on a pothole - and it pulled the lower heim with it....
ira stands behind his stuff.

QUOTE (Ira Ramin @ Aug 2 2005, 07:25 PM)

Rotating them will probably cause binding when the car is jacket up and the front suspension drops. They may also bind when the suspension is compressed.

hey ira, i'll take pictures tomorrow and post them here. the reason why i moved the u-tabs 90 deg. was because with the swaybar on full soft (where i was running it) the heim-joint would hit the top of the u-tab under normal operation.
might had to do with the drop-links as they were too long for my setup. both heims are screwed in completely to make the droplink as short as possible, still, on full soft or full tight they would hit.

with the u-tabs turned 90 deg, the only time they would hit was on full decompression (car on the lift) ...

it'll make more sense with pictures ...
Andy

Andy,
Your explanation makes full sense, and I’ve heard of 914’s not being able to be set full soft before. I’ve also heard of them being set full soft without any problems, so I’m not sure what the problem is. It may just be on the edge of working, or not working in this case. Anyone else seeing this, please let me know? It looks ok on my 911, but the 914 swaybar may be in a slightly different location to clear the gas tank.

Here is the drop link at full tilt. The rod end is hitting on the spacer before it can touch the bracket. This is on of my brackets, but the factory one is similar. If your bracket is higher and hitting, maybe it can be shortened. If the spacer is causing the problem, maybe I can change it to allow for more clearance.

What do you think about a compromise of rotating the bracket 45 deg.? Either way, we need to get it back together and figure out what the problem is. Let me know what you need and where to send the parts. No charge, I just want to solve this. I’ll be out of town next week, so let me know soon if you need parts before then.

Thanks,
Ira

Now, that, my friends, is what I call Customer Service!!!

--DD

Way to go IRA! Your stock just jumped big time in my book. This is the way to run business. Lots of companies ignore problems like this. You rock man.

I was considering a Tarett bar for my car,now I know I'll get one!!!!!

SteveSr

Yep, that'll do it for me too. The RS is getting one of Ira's bars.

Hey Ira, how about a group deal? I bet you could sell 20 of these today.

QUOTE (914RS @ Aug 4 2005, 08:25 AM)

Yep, that'll do it for me too. The RS is getting one of Ira's bars. Hey Ira, how about a group deal? I bet you could sell 20 of these today.

oh no...the dreaded "group buy"...run...run....

I guess Joe was not around for "that" one...got a little ugly...

QUOTE (Mueller @ Aug 4 2005, 08:30 AM)

oh no...the dreaded "group buy"...run...run.... I guess Joe was not around for "that" one...got a little ugly...

Yeah , guess I missed that one...

QUOTE (914RS @ Aug 4 2005, 08:45 AM)

QUOTE (Mueller @ Aug 4 2005, 08:30 AM) oh  no...the dreaded "group buy"...run...run.... I guess Joe was not around for "that" one...got a little ugly... Yeah , guess I missed that one...

a few years ago Ira agreed to do a group buy for his swaybars thru the 'club...someone started to post the deal on other sites....people who bought bars in the past got upset*, shops got upset and since Ira sells my roller bearing kits, people "assumed" these would be marked down as well and it just got ugly...I posted my bearings would not be part of a group buy..period

Ira ended the group buy for his bars and I think he honered a few purchases...Ira is a stand up guy a true trooper when it comes supporting us 914 guys

*asking for a refund of the difference

I see. Well that sucks.

I had already pretty much decided that the RS was getting this bar, but I haven't done much pricing. Who has the best prices on these?

all about the same; if you really want to support Ira buy direct. he won't undercut his distributors with lower pricing but he won't have to pay their cut either.

i will be running a different bar in the 911 (it a preference thing...) but i will DEFINITELY run Tarett droplinks. they're the only ones who "get it" that 10mm hardware is required. there is no question that the Tarett bar is a much nicer part than the WeltMeister it is frequently compared against.

alright, let me say first that i really apprechiate Ira's offer of replacing the parts for free,
but i will have to kindly decline.

obviously, whatever happend, it had nothing to do with the material or quality or layout of his swaybar and i feel if i took him up on his offer, i'd be cheating him out of some well deserved money.

so, whatever parts i'm going to need, i'll be more than happy to pay for! (gee, what a concept ...)

now here are the blurry pics ...
---------------------------------------------

drivers side:

note how the hime joint is stuck all the way towards the outside of the car. it was so much in bind that i could move it back by hand ...


this is how it's supposed to line up with the car on the ground ...


closeup. NOTE: how the U-Tab is bend to the left but the joint broke at full tilt to the right!
i am guessing the tab bend to the left when the car was on the lift with the weight of the wheels and the joint hitting the top of the tab.
then, when i hit whatever pothole it must have been, the joint moved all the way to the right under compression and snapped ...

pass side:

same here, hime joint was stuck towards the outside of the car ...


nuther, showing how it's supposed to line up ...


closeup, again, the actual u-tab is bend the other way ...


one more, more sharp this time ...

and out of the car ...

I wonder if moving the link out .25" to .375" would help any?
I would be a little concerned of "twisting" the arm with the link out too far.

so it looks like all i need is two lower hime-joints with the set screws, one left and one right thread ...

also, how important is it to keep the "arm" of the sway bar level with the ground (i heard that is the optimal position) because if i make my droplinks *longer* it'll take out a few degrees in angle and i might clear the u-tabs better ...

oh, and the bushings had marks and were deformed on the top on both sides, so the joints were definately in a bind. but that could have happened with the car on the lift.

as you can see from the pics, under normal load, the joint were nicely centered on the tabs ...
Andy

QUOTE (Mueller @ Aug 4 2005, 11:55 AM)

I wonder if moving the link out .25" to .375" would help any? I would be a little concerned of "twisting" the arm with the link out too far.

if anything i need to move it *IN* and not out. with the lower joint pointing outward when it snapped, that means the upper part was too far *out* at full compression ...

Andy

PS: thank god you're an engineer ...

I've been running Ira's bar in the front of my car for a couple years....set on full soft.
The venue I AX on is god awful rough, but have had zero problems. If I ever get an LSD, I'll spring for his rear bar....if I have any money left

Hay Andy: Them pics ain't bad. I guess there's hope for you after all

QUOTE (J P Stein @ Aug 4 2005, 12:00 PM)

I've been running Ira's bar in the front of my car for a couple years....set on full soft.

just to clarify ...

when in first installed this bar i had the u-tabs in the stock location AND stock rotation. on full soft, the hime joints would hit the top of the u-tab at just minor compression/decompression ...

when i got my new a-arms i opted for rotating the u-tabs 90 deg. because it seems to give me more free play around normal load situations and only hit on full decompression (on the lift)

Andy

Pics of the actual failure site may be able to tell us if it went all at once, or if it fatigued into failure over repeated cycles. Not sure that is valuable info any more, because it seems pretty obvious what happened...

--DD

QUOTE (Dave_Darling @ Aug 4 2005, 12:13 PM)

Pics of the actual failure site may be able to tell us if it went all at once, or if it fatigued into failure over repeated cycles.

hmmm, this is interesting ...

it almost looks as if the joints are made out of two materials, the outside (the thread) is still nice and shiny while the inside is rusted ...
but it hasn't rained here in weeks and that just happened 2 weeks ago!

btw. my camera *sucks* for closeups ...

other side ...

one more ...

Maybe you bent the tabs on a full decompression (go off any jumps lately?) and then broke the heim joints on full compression.

Got me thinking that when I went to put the mounts on the A-arms for my race car someone (forget who) told me to align the bolt holes fore-aft and not crossways as Andy has his. Wonder if that makes any difference? I agree about the upper mount moving out slightly with a spacer since the heim joint looks like it is bolted solid against the arm?

QUOTE (john rogers @ Aug 4 2005, 12:28 PM)

Got me thinking that when I went to put the mounts on the A-arms for my race car someone (forget who) told me to align the bolt holes fore-aft and not crossways as Andy has his. Wonder if that makes any difference? I agree about the upper mount moving out slightly with a spacer since the heim joint looks like it is bolted solid against the arm?

looking at it again, no need for a spacer, just flip the arm

Andy, can you cut part of the remaining thread to get a fresh cross section?

QUOTE (john rogers @ Aug 4 2005, 12:28 PM)

I agree about the upper mount moving out slightly with a spacer since the heim joint looks like it is bolted solid against the arm?

huh? moving the upper mount outward would make it even worse ...

the lower joint broke off while it was pointing outward. it must have been in a hell of a bind as it was stuck in that position because it had deformed the spacers ...

moving the upper mount outward will simply result in the same thing happening much earlier with much less compression.

you guys gotta need to take some geometry classes ...
Andy

QUOTE (SirAndy @ Aug 4 2005, 12:36 PM)

huh? moving the upper mount outward would make it even worse ...

my second statement was "if" you had to move it in that direction.....

I figure the lower heim joint broke off while it was pointing inward, at full compression.

This is hard for me to explain, but I think the problem is the 90 re-orientation of the u-tabs and I think the axis of the heim joint on the a-arm needs to be parallel to the axis of the a-arm itself.

If you put a big plate (green lines) into the rotated u-tab, you'd see that the plane of the plate (especially the top) move inward and outward through the a-arm travel. However, the top of the droplink in fixed in its left-right orientation, and at some point the droplink tries to bend.

The forces on the utab (yellow) push down, but since the u-tab is at an angle, 'down' is also 'inward'.

(The left side of the picture is at ride height, the right side is my interpretation of a-arm, u-tab orientation at full compression.)

QUOTE (john rogers @ Aug 4 2005, 11:28 AM)

Got me thinking that when I went to put the mounts on the A-arms for my race car someone (forget who) told me to align the bolt holes fore-aft and not crossways as Andy has his. Wonder if that makes any difference?(snip)

It IMHO makes all the difference in the world. Andy, this isn't meant as a jab, but I'll stake (what little there is of) my reputation on this statement - This failure has everything to do with the U-tabs being rotated 90 degrees from the original design. You eliminated one form of binding and unintentionally exchanged it for a worse one. In the stock orientation the control arm can move through it's entire arc without changing the angle of the heim joint pieces - The outer joint piece rotates around the axis of the through bolt. With the tabs rotated 90 degrees the angle of the outer joint piece to the axis of the ball changes dramatically as the control-arm moves. It wouldn't take very much control-arm angle change to bind and snap off the heim joints.
Since you changed the U-tabs to give more adjustment I think the root of this is recognizing that we're trying to get too much range of adjustment out of this swaybar. I think the solution is putting the U-tabs back in the stock orientation and living with less adjustment.

-Ben M.

QUOTE (Cloudbuster @ Aug 4 2005, 12:00 PM)

This is hard for me to explain, but I think the problem is the 90 re-orientation of the u-tabs and I think the axis of the heim joint on the a-arm needs to be parallel to the axis of the a-arm itself.

Thank you Mark. You said that MUCH better than I did. (Good illustrations too)
-Ben M.

QUOTE (Cloudbuster @ Aug 4 2005, 01:00 PM)

I figure the lower heim joint broke off while it was pointing inward, at full compression. ...

yes, you are correct with all of the above.

the problem with the stock rotation was that i could not run the bar on full soft (or close to it, or full tight or close to it) as the heim joint would bind on the top of the u-tab as well (on normal load!) ...

effectively depriving me of the use of ~ 1/3 rd of the bar ...

again, my question would be, how important is it to have the "arm" parallel to the ground?
if i could make the droplinks much longer, i'd be able to get around the problem, but then the arm would be up in an 45 degree angle with the car on the ground ...

Andy

QUOTE (SirAndy @ Aug 4 2005, 01:16 PM)

again, my question would be, how important is it to have the "arm" parallel to the ground? if i could make the droplinks much longer, i'd be able to get around the problem, but then the arm would be up in an 45 degree angle with the car on the ground ...

ok, i'm just going to answer my own question here ...

making the droplinks longer would help getting rid of the binding problem, but in effect all i'd do is exactly the same as not using both end of the sway bar arm in the current setup.
thus limiting myself to only ~2/3rd (if i'm lucky) of the possible adjustment ...

there has to be a better solution for this ...

can i grind down the top of the u-tabs? if so, how much would still be safe?
how about a lower mount that goes around the small round support rod on the a-arm with a top that can move freely and won't hit anything?
how about a hole through the a-arm with some sort of joint on the top that can move freely?

Andy

how about having 2 sets of U-tabs?

It's tough to tell from the pics (mostly due to the rust or whatever is there), but I don't see the "broach marks" that signal a progressive failure. Then again, my main examples are from Carroll Smith's books, and those may have been spiffed up for photographing. Anyway, it looks like a one-time catastrophic failure to me.

Would it make sense to trim town the tops of the "U" to get back your full range of adjustment, once the tabs are the correct way around? Or perhaps to make them wider, and use thicker spacers? I'm just trying to toss ideas around.

--DD

Has anyoner snapped a bolt off? Remember what heppened? There was a large amount of kickback and I would almost bet that is what happened here. The threaded part broke at the other extreme and the shock/force of the snapping action caused the heim joint to wedge the other way. In looking at the picture above with the A-arm compressed, that is a huge amount and I would think the inserts would have bottomed well before hat could have happened? From the picts of the car if I remember it is already sitting low and I would bet the compression is not that great, but from the looks of the suspension travel I bet there is a large amount of extension when lifting that inside front wheel. If it were me, I'd pull a strut insert to see what kind of rebound and compression the insert has?

I don't think heim joints are compatible with this bar's full range of adjustment. Mueller has the right idea - two or more sets of U-tabs (assuming there is room on the control-arm).

-Ben M.

ps - I think it's a good product (the bar) and I wish there was one on my car. I think we're just trying to get too much adjustment range out of this design and taking the geometry to the extreme.

Even if the droplink is shortened, the mounting point need to go forward, so...

I'd take a block of steel and drill / tap it for the droplink crossbolt. Weld the block onto the top of the a-arm with the bolt hanging off in front of the a-arm body. Orient the bolt fore-aft. This gives all the articulation space necessary to get the swaybar to full soft, and solves the issue of too-long droplinks.

Problems are:
1) the bolt in in single shear instead of double. A real shoulder bolt that fits inside the mounting block would help
2) there's even more binding on the heim joint trying to set the bar to full stiff. This should not really be a practical concern, unless you are running a prototype rear swaybar (2x stiffer than stock) and 200 lbs springs.