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914World.com _ 914World Garage _ tarett swaybar stuff broke ...
Posted by: SirAndy Jul 25 2005, 01:10 PM
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
Posted by: Cloudbuster Jul 25 2005, 01:18 PM
Didn't you weld on the u-tabs rotated 90 degrees from the stock orientation? (Stock = the bolts run fore-aft)
Posted by: ArtechnikA Jul 25 2005, 01:25 PM
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...
Posted by: Dave_Darling Jul 25 2005, 01:38 PM
(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
Posted by: ChrisReale Jul 25 2005, 02:11 PM
| 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.
Posted by: ArtechnikA Jul 25 2005, 02:24 PM
| 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 :-)
Posted by: kwales Jul 25 2005, 03:13 PM
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....
Posted by: SirAndy Jul 25 2005, 04:01 PM
| 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
Posted by: MattR Jul 25 2005, 04:08 PM
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 
Posted by: Ira Ramin Aug 2 2005, 08:25 PM
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
Posted by: Aaron Cox Aug 2 2005, 09:13 PM
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.
Posted by: SirAndy Aug 2 2005, 10:05 PM
| 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
Posted by: Ira Ramin Aug 3 2005, 11:27 PM
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
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Posted by: Dave_Darling Aug 3 2005, 11:53 PM
Now, that, my friends, is what I call Customer Service!!!
--DD
Posted by: McMark Aug 4 2005, 01:27 AM
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.
Posted by: SteveSr Aug 4 2005, 08:45 AM
I was considering a Tarett bar for my car,now I know I'll get one!!!!! 
SteveSr
Posted by: Series9 Aug 4 2005, 09:25 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.
Posted by: Mueller Aug 4 2005, 09:30 AM
| 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...
Posted by: Series9 Aug 4 2005, 09:45 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...
Posted by: Mueller Aug 4 2005, 09:55 AM
| QUOTE (914RS @ Aug 4 2005, 08:45 AM) | ||
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
Posted by: Series9 Aug 4 2005, 09:59 AM
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?
Posted by: ArtechnikA Aug 4 2005, 10:08 AM
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.
Posted by: SirAndy Aug 4 2005, 12:45 PM
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 ...
---------------------------------------------
Posted by: SirAndy Aug 4 2005, 12:49 PM
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 ...
Posted by: SirAndy Aug 4 2005, 12:53 PM
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 ...
Posted by: SirAndy Aug 4 2005, 12:54 PM
and out of the car ...
Posted by: Mueller Aug 4 2005, 12:55 PM
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.
Attached image(s)
Posted by: SirAndy Aug 4 2005, 12:57 PM
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
Posted by: SirAndy Aug 4 2005, 12:59 PM
| 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 ...
AndyPS: thank god you're an engineer ...
Posted by: J P Stein Aug 4 2005, 01:00 PM
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
Posted by: SirAndy Aug 4 2005, 01:06 PM
| 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
Posted by: Dave_Darling Aug 4 2005, 01:13 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. Not sure that is valuable info any more, because it seems pretty obvious what happened...
--DD
Posted by: SirAndy Aug 4 2005, 01:23 PM
| 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 ...
Attached image(s)
Posted by: SirAndy Aug 4 2005, 01:24 PM
other side ...
Attached image(s)
Posted by: SirAndy Aug 4 2005, 01:24 PM
one more ...
Attached image(s)
Posted by: McMark Aug 4 2005, 01:24 PM
Maybe you bent the tabs on a full decompression (go off any jumps lately?) and then broke the heim joints on full compression.
Posted by: john rogers Aug 4 2005, 01:28 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?
Posted by: Mueller Aug 4 2005, 01:35 PM
| 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?
Posted by: SirAndy Aug 4 2005, 01:36 PM
| 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
Posted by: Mueller Aug 4 2005, 01:38 PM
| 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.....
Posted by: Cloudbuster Aug 4 2005, 02:00 PM
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.)
Attached image(s)
Posted by: airsix Aug 4 2005, 02:13 PM
| 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.
Posted by: airsix Aug 4 2005, 02:15 PM
| 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.
Posted by: SirAndy Aug 4 2005, 02:16 PM
| 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
Posted by: SirAndy Aug 4 2005, 02:22 PM
| 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
Posted by: Mueller Aug 4 2005, 02:29 PM
how about having 2 sets of U-tabs?
Posted by: Dave_Darling Aug 4 2005, 02:49 PM
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
Posted by: john rogers Aug 4 2005, 03:10 PM
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?
Posted by: airsix Aug 4 2005, 03:13 PM
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.
Posted by: Cloudbuster Aug 4 2005, 03:53 PM
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.
Attached image(s)
Posted by: jkeyzer Aug 4 2005, 04:04 PM
Maybe the solution is a different diameter bar???
Avoid this whole mess...
Posted by: SirAndy Aug 4 2005, 04:07 PM
i like the idea of U-Tabs that are simply wider plus using wider spacers.
that would give me all the room i need to use the full adjustment of the bar (with the u-tab back in the stock rotation) ...
stock: |_||_|
wider: |___||___|
that should solve the problem, right?
Andy
Posted by: SirAndy Aug 4 2005, 04:08 PM
| QUOTE (jkeyzer @ Aug 4 2005, 03:04 PM) |
| Maybe the solution is a different diameter bar??? Avoid this whole mess... |
nope, i need to step up on my rear springs some more anyways, a smaller bar would be counter-productive ...
Andy
Posted by: Demick Aug 4 2005, 04:15 PM
| QUOTE (SirAndy @ Aug 4 2005, 03:07 PM) |
| stock: |_||_| wider: |___||___| |
Maybe - maybe not. It depends on if the hiem joint hits it's own limit before or after it hits the bracket. In this picture that Ira posted, it looks like the heim joint will hit it's limit before it will hit the bracket. So making the U-tab wider won't help.
However, the limit is partially based on the diameter of the spacers. Some spacers that taper to the min diameter necessary as it approaches the heim joint will increase the range of the joint.
Demick
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Posted by: Demick Aug 4 2005, 04:20 PM
Another consideration is that the lower heim joint range is not the issue - it could be the upper heim joint. I'm going just by pictures here, but the way that the upper joint is mounted it looks like the big washer severely restricts the amount of side to side motion of the drop link. If the top one binds (under decompression when the A-arm is extended which pulls the lower mounting point inboard), it will try to bend the drop link, and that could cause the bottom joint to fail.
Demick
Posted by: SirAndy Aug 4 2005, 04:23 PM
here's another observation ....
the way the top hime joint is mounted, without spacers and large washers on each side, it's *very* limited in how much it can move ...
maybe adding 2 spacers like on the bottom would help getting more movement out of the top joint ...
Andy
Posted by: SirAndy Aug 4 2005, 04:24 PM
| QUOTE (Demick @ Aug 4 2005, 03:20 PM) |
| it could be the upper heim joint. |
damm, you beat me to it ...
Andy
Posted by: Demick Aug 4 2005, 04:31 PM
| QUOTE (SirAndy @ Aug 4 2005, 03:24 PM) |
| damm, you beat me to it ... Andy |
Hey Andy - as long as I'm 1 second faster than you - I'm happy. Especially on the Autox course.
Demick
Posted by: SirAndy Aug 4 2005, 04:34 PM
| QUOTE (Demick @ Aug 4 2005, 03:31 PM) |
| Hey Andy - as long as I'm 1 second faster than you - I'm happy. Especially on the Autox course. |
don't get too used to it ... i'm still learning ...
Andy
Posted by: jonwatts Aug 4 2005, 04:35 PM
Is our application different than a 911? I'm confused as to whether or how this is a 914 only problem.
Interesting discussion.
Posted by: john rogers Aug 4 2005, 04:39 PM
The upper mount being tight against the sway bar is what I was refering to as there is no sideways movement it appears. If you get some new heim joints, I'd say to put the car up on jack stands in the front and test the A-arm travel with the bar hooked up on both sides and also with one side unhooked to see what is binding and what kind of clearances there are. This might mean devising a way to push the A-arm up to simulate full braking compression and pull the A-arm down to simulate a hard corner. This would be the only way short of mounting a video camera down there to see what is happening. I did this 6 years ago when we put the sway bars in the race car to make sure nothing was binding.
Posted by: SirAndy Aug 4 2005, 04:43 PM
| QUOTE (john rogers @ Aug 4 2005, 03:39 PM) |
| This would be the only way short of mounting a video camera down there |
a video camera, eh?
Posted by: airsix Aug 4 2005, 05:26 PM
| QUOTE (SirAndy @ Aug 4 2005, 02:43 PM) |
| a video camera, eh? |
It would be cheaper and easier to use a pencil, paper, and geometry.
Bottom line is that heim joints are not designed to see huge angle changes. They are intended for MINOR angle changes.
Put the U-tabs back in the correct orientation and run the bar at a possition that keeps the geometry correct. If you can't run the the bar at the stiffness you want without putting the heim joints into bind then you need a different weight bar.
-Ben M.
Posted by: SirAndy Aug 4 2005, 05:38 PM
| QUOTE (airsix @ Aug 4 2005, 04:26 PM) |
| If you can't run the the bar at the stiffness you want without putting the heim joints into bind then you need a different weight bar. |
no really. problem here is that i don't run the bar at just one setting and that's it.
the car is also my daily driver and on the road i like to have some understeer, however, for the AX course, i like some mild oversteer.
i adjust the bar frequently. for the street usually full soft (which put the hime joints in bind on the stock setup), on the track stiffer.
i'd like to get the car balanced so it's neutrual in the middle and i don't need that much adjustment either way, but i'm not sure that'll ever happen.
i went with a adjustable sway bar so i could *adjust* it.
what's the point to just have one setting?
Andy
Posted by: Cloudbuster Aug 4 2005, 05:47 PM
The problem is that the upper heim joint is fixed in space inboard/outboard wise, but the lower end in moving in/out through its travel. Added spacers to give the upper joint greater articulation doesn't really change the geometry. As a matter of fact, pushing the upper heim joint outboard would make the situation worse.
As for why this is a 914 specific problem, I think the target application for the bar was the 911. It just happens to fit in a 914. Mostly. As long as you don't run the u-tabs sideways.
Posted by: McMark Aug 4 2005, 06:08 PM
Did the heim joint run into the UTab or the spacers?
Seems like if the spacers weren't so large, you'd gain another 5-10 degrees of freedom.
Posted by: SirAndy Aug 4 2005, 06:14 PM
| QUOTE (McMark @ Aug 4 2005, 05:08 PM) |
| Did the heim joint run into the UTab or the spacers? Seems like if the spacers weren't so large, you'd gain another 5-10 degrees of freedom. |
on the top?
yes. no spacers on the top, just large washers. the heim joint on the top hits the washers long before it reaches it's maximum angle ...
so yes, there's probably at least 10 deg. more to each side in there ...
on the bottom, the heim joints hit the top of the u-tab and deformed the spacers ...
Andy
Posted by: McMark Aug 4 2005, 06:27 PM
On the bottom. The top seems irrelevant, since it's not binding.
This picture seems to clearly show that the UTab isn't the problem, the spacers are. At least from where I'm sitting.
Attached image(s)
Posted by: SirAndy Aug 4 2005, 06:29 PM
| QUOTE (McMark @ Aug 4 2005, 05:27 PM) |
| This picture seems to clearly show that the UTab isn't the problem, the spacers are. At least from where I'm sitting. |
yes, with a new part sitting on a nice glas table, sure ...
on my parts, in the car, under load, the hime-joint *DID* hit the top of the u-tab and deformed the spacer ...
Andy
Posted by: Demick Aug 4 2005, 07:10 PM
| QUOTE (SirAndy @ Aug 4 2005, 04:38 PM) |
| the car is also my daily driver and on the road i like to have some understeer, however, for the AX course, i like some mild oversteer. i adjust the bar frequently. for the street usually full soft (which put the hime joints in bind on the stock setup), on the track stiffer. |
You've got something backward. If you want understeer on the street, you need to stiffen the bar. For autox if you want some oversteer, you need to soften the bar.
Posted by: Ira Ramin Aug 4 2005, 07:20 PM
Lets keep in mind that my picture is with my u-tab. Andy’s may be different. So are you saying that the rod end is hitting both the u-tab and the spacer? If so, then there should be room to cut the u-tab back enough to clear. Additionally, I may be able to modify the spacers to get enough additional motion to fix this. I think that it will at least help, if not resolve the problem completely.
It appears that some cars have no problems and some (two that I know of so far) do. I’d like to figure out why there’s a difference so I can come up with the best solution. The other car that I know of, with the limited adjustment range, is local to me. Maybe, if I ask nicely, he’ll let me come by and check it out.
Posted by: jonwatts Aug 4 2005, 07:24 PM
I wonder if this is all just a matter of the factory U-tabs not being uniform but good enough for factory sway bars?
Thanks to Ira for giving this proper attention and not taking our comments as criticisms. Sometimes group engineering can be a good thing (but not usually).
Posted by: SirAndy Aug 4 2005, 07:47 PM
| QUOTE (Demick @ Aug 4 2005, 06:10 PM) |
| You've got something backward. |
yeah, the other way ...
on AX i ran full soft (sometimes even disconnected the bar) and on the street i ran it stiffer (towards the back) ...
i'd like to get my suspension dialed to the point where i can play with all of the bar for AX and just set it on full firm for the street ...
but that's another thread ...
Andy
Posted by: SirAndy Aug 4 2005, 07:57 PM
| QUOTE (Ira Ramin @ Aug 4 2005, 06:20 PM) |
| I’d like to figure out why there’s a difference so I can come up with the best solution. |
i believe the u-tabs came with your kit as those a-arms didn't have tabs on them ...
i'll try to take another closeup of those tomorrow.
for now, here are a few closeups of the (deformed) spacers ...
NOTE: each of the spacers was the outside spacer on the lower himejoint.
Attached image(s)
Posted by: SirAndy Aug 4 2005, 07:58 PM
sideways
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Posted by: Demick Aug 4 2005, 07:59 PM
| QUOTE (jonwatts @ Aug 4 2005, 06:24 PM) |
| I wonder if this is all just a matter of the factory U-tabs not being uniform but good enough for factory sway bars? |
Remember that Andy's are not factory u-tabs. Are we sure that Andy's u-tabs are placed properly?
Also remember that the optimum placement may not be where the factory u-tabs were placed. This is an aftermarked sway bar and may have the drop links positioned slightly differently than stock (further outboard or inboard).
Demick
Posted by: Demick Aug 4 2005, 08:01 PM
so clearly the heim hit the spacers before hitting the u-tabs. That's some pretty good deformations.
Demick
Posted by: SirAndy Aug 4 2005, 08:02 PM
| QUOTE (Demick @ Aug 4 2005, 06:59 PM) |
| Remember that Andy's are not factory u-tabs. Are we sure that Andy's u-tabs are placed properly? |
that's a question you'll have to ask brad as he welded them on. he did use a factory u-tab equipped a-arm as reference and i'm pretty sure he got them welded in the correct place ...
and yes, IIRC those are Ira's U-Tabs ...
Andy
Posted by: Cloudbuster Aug 4 2005, 08:27 PM
It looks as if those u-tabs ARE too far inboard. According to my (3rd) spare set of factory a-arms, the bolt hole should be even with the inside corner of that tubular brace on the a-arm. (No camera, so I get to play with Paint some more)
Attached image(s)
Posted by: Eric_Shea Aug 4 2005, 08:31 PM
Those U-Tabs look to be about 1/2" too far inward from "both" of my cars with stock tabs.
To try to explain... my outer edge is almost directly over the a-support that comes into view on those pics and is welded to the arm. (does that make sense? )
Both my cars have the factory mount placed "outward" by what appears to be 1/2". NOW... they're "both" 911 A-arms on the GT and the RS so... I don't know if that makes any difference.
I'd go take some pics but I don't want to piss off the Sir with my clearly superior photographic skills 
(actually, I'm too fuching lazy... I will if you need or request "Oh Sir One")
Posted by: SirAndy Aug 4 2005, 08:35 PM
| QUOTE (Eric_Shea @ Aug 4 2005, 07:31 PM) |
| I will if you need or request "Oh Sir One" |
yes, please do so Sir Eric-o-lot !
btw. mine are 911 A-Arms as well. hmmmm, could there be a difference that i'm not aware of?
Andy
Posted by: SirAndy Aug 4 2005, 08:37 PM
| QUOTE (Cloudbuster @ Aug 4 2005, 07:27 PM) |
| It looks as if those u-tabs ARE too far inboard. According to my (3rd) spare set of factory a-arms, the bolt hole should be even with the inside corner of that tubular brace on the a-arm. (No camera, so I get to play with Paint some more) |
hmmm, now would be a good time for a picture of a factory u-tab on a a-arm ...
Andy
Posted by: Demick Aug 4 2005, 09:27 PM
ask and you shall receive.....
Here's a pic of my passenger side a-arm with factory tab. The two lines represent the centerline of the u-tab where the bolt goes through, and the centerline of the bracing where it intersects the main part of the a-arm. That distance is about 1/2" (the u-tab being inboard of the CL of that brace)
Demick
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Posted by: McMark Aug 4 2005, 10:09 PM
And roughly 6" from the torsion tube to the edge of the U Tab. That is the distance between the two, not including either. (Wouldn't that be called the exclusive distance?)
Posted by: cametal Aug 4 2005, 10:10 PM
Mabee a new mount on the bar area of the control arm. This will move the mount foward. This is what I needed for my bar (Weltmiester) on full soft.
I copied these from a friends 911. I don't know who makes them.
Don't pay any attention to the spiders!
Attached image(s)
Posted by: SirAndy Aug 4 2005, 10:34 PM
| QUOTE (Demick @ Aug 4 2005, 08:27 PM) |
| ask and you shall receive..... |
thank you sir!
sooooo, is there a difference between the 914 a-arm and the 911 a-arm?
like in the placement of the small rod and/or u-tab ???
Andy
Posted by: trekkor Aug 4 2005, 11:03 PM
| QUOTE |
| 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? |
That's the set up that is used with SRP's front bars.
If you can't pivot the drop links with the car on the ground, that is a problem to start with.
The hime joints need to be centered and parrelell with the u-tabs.
here's the drops attached to the stock u-tabs.
KT
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Posted by: trekkor Aug 4 2005, 11:12 PM
Here's the lower mounts installed below the stock u-tabs.
You can buy just the lower mounts from Smart.
KT
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Posted by: SirAndy Aug 4 2005, 11:19 PM
| QUOTE (trekkor @ Aug 4 2005, 10:03 PM) |
| here's the drops attached to the stock u-tabs. |
trek, with that setup, how far can you move the bar back (tighter) before the lower himejoint hits the u-tab (or is out of movement) ???
from your pic, it looks like it would hit long before you reach the end of the bar (to the right) ...
Andy
Posted by: trekkor Aug 5 2005, 12:22 AM
I have never raced with the stock u-tabs.
When I showed up with the Smart bar installed for the first time Rich Walton of SRP happened to be there and helped me set-up the lower mounts.
The nice feature with the Smart mounts is you can aim them at the bar so you always have bind free operation.
Buy a set, no matter what bar you run.
KT
Posted by: Ira Ramin Aug 5 2005, 07:48 AM
Ok Andy, I have an idea that will solve your problem. When you install the new u-tabs in the stock location and orientation, angle them forward enough to get full forward adjustment without binding. Just prop up the back of the tab a little when you weld them in. Make sure it’s not too much, or you could loose rear adjustment.
Ira
Posted by: SirAndy Aug 5 2005, 09:58 AM
| QUOTE (Ira Ramin @ Aug 5 2005, 06:48 AM) |
| Just prop up the back of the tab a little when you weld them in. |
hmmm, that could work ...
i'll try to get the u-tab as close as possible to center in regards to the swaybar arm.
a slight tilt could help aiming it in the right direction ...
i'll report back. thanks for all the input, guys ...
Andy
Posted by: Jeroen Aug 5 2005, 01:42 PM
here's a pic of the location of the stock u-tabs
Attached image(s)
Posted by: SirAndy Aug 5 2005, 02:26 PM
| QUOTE (Jeroen @ Aug 5 2005, 12:42 PM) |
| here's a pic of the location of the stock u-tabs |
now that is very helpful!
thank you, my metric friend ...
Andy
Posted by: Jeroen Aug 5 2005, 02:32 PM
I just took a look at my tarret droplinks (have been installed on my 911)
The spacers on the bottom rod-end have been slighly squashed, but only in one direction
(I'm trying to visualize in what position that is)
I'll post pics of them later on...
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