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7/8" Sway Bar Ripped Out

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Tullamore

Tullamore

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A couple months ago I installed a 7/8" Anti-Sway bar on my sprite. Within the first week it had pulled apart the ball joint on the left side. I was sent a new one free from Victoria British and had not had another problem until tonight. Tonight the ball joint again pulled out (different ball joint than before, but in same location) and the sway bar mounts on both side ripped completely out of the frame. /ubbthreads/images/graemlins/frown.gif

IMG_4147.sized.jpg
 
Well, in the first place, I have to ask, "What ever possessed you to run a 7/8" bar on the front of a Spridget in the first place?"
Good Lord, I only run a 3/4" maximum on the race car, and it has reinforced mounts both on the frame and the control arms. For normal track use, it's an 11/16" bar, and never a rear bar.
A 7/8" bar is way too much. It transfers too much force from the suspension into areas that aren't intended for that much stress.
Wasn't it a bit "squirrely" with that setup?
Jeff
 
From the pic, I believe that the frame section where the bar is mounted shows serious frame damage/weakening from rust. Stiffer bars & shocks put a good deal more stress on the chassis mounting points. You could maybe solve the problem by reinforcing the mounting points and/or replacing the rust damaged metal.

I think a 7/8" bar is about 6 times as stiff as a 9/16" bar & requires considerably stronger mounting points. An 11/16" bar would only be about 2.2 times as stiff as a 9/16" bar.
D
 
Hi Tullamore, Yes the frame in that section is rusted.The method we use to repair this area is:Cut the rusted section out to the side rails. Using 5/16 steel make new bottom plates and tap the holes for the sway bar mount. This plate then is welded in to replace the former bottom of the frame and ground to be flush. Comments on your choice of bar size are valid . If cost is a concern and you are not too much concerned with appearances it may be easier to make a plate that begins at the front of the frame and extenda all the way back to the rear of the front cross member. The exixting metal is ground clean in the areas to be welded and its welded up---Fwiw---Keoke
 
Keoke, I was planning on doing exactly as you mention, by replacing the old rusted area with new metal. I just posted the picture to show what can happen under the stress caused by a large sway bar.

The rails seemed very solid when I bolted on the bar a couple months ago. Smacking it with a hammer made a nice solid tone, there is just no telling what damage rust can do when water can enter from the inside.
 
NO no, That kind of rust does not occur over two months time and what you see is just the tip of the iceberg. The repair work will take patience and time.I hope it turns out ok for you.---Keoke----PS If you smack good metal with a hammer it should Ring!
 
Interesting post... as part of my restore, I was considering a little larger sway bar to give the car better handling. but, as mine will be a daily driver, and after seeing what could happen, maybe I'll just stick with the stock sway bars. I think a 3/4 bar would be a bit much for normal road driving.
 
I had a Sprite with a 7/8 sway bar. It was WAY to much!
I am currently running a 3/4 bar with nothing in the back and for the way I drive on the street, it works great for me.
It is probably a tad too much for normal street use.

Frank
 
I drive with an (unreinforced) 3/4" bar, lowered/stiffer springs front and rear, STP in my lever shocks all around, and DOT approved race tires w/ rear panhard rod, as mentioned several times previously. I meant to post about this before, but I am experiencing some interesting effects. I have the bar (which is slightly adjustable) at the stiffest setting. I regularly see significant front wheel lift, as shown in this picture:

https://teamwtf.org/index.php?set_albumNa...=view_photo.php

I also seem to have a slight understeer. However, a more annoying problem is rear-end breakaway. Regardless of wether I'm heading up hill or down, and even on varying pavement conditions (some bumpy, some quite smooth), I get breakaway with sudden throttle lift. I don't even seem to have to hit the brakes to have the rear end come around accidently. I even let another member drive my car yesterday at our event in Allentown PA (who is among the top ten or so at most events, with 150-200 entries). He too had this problem both times that he drove it. He managed to catch it quickly, but it happened nonetheless. He has a smoother (more experienced) style, and that should help mitigate the situation, but it doesn't seem to eliminate it. Any thoughts? I also think I'm getting far too much rear body roll. The tires just scrub on the inner portion of the wheel well, even with the panhard rod. My theory is that the panhard rod lowered the roll center enough to allow increased rear body roll, making the roll resistance unbalanced between the front and rear of the car, whereas when the roll center was slightly higher, the roll resistance was increased and therefore, the stock swaybar (or a slightly heavier one) would have only desireable effects. Just throwing that out there.

Sorry for hijacking the thread,
Matt
 
Hi Matt,
Actually a sway bar, anti roll bar, will pick up the inside tire when weight is transfered to the outside & compresses the outside spring. The ultimate effect would be with no springs so that the inside tire lifted anytime the body was tilted. A rear sway bar would tend to pick up the inside rear tire the same way. Guess you have a choice of going through the corner on three wheels or two. BTW, there is always more available cornering traction with two front wheels or two rear wheels on the ground. Anytime a wheel lifts, there is less total traction available. Sometimes this can be used to balance the front/rear breakaway. The body roll is always the same front & rear, unless the frame twists, so the only effect is how much the inside suspension/tires unload. The only problem with body roll is that on most cars, it upsets the camber & produces less tire grip.
D
 
...I regularly see significant front wheel lift, as shown in this picture:...

I have my own opinion about your wheel lifting: One of our Spridget guys is still running lever shocks (the rest of us are using tube shocks). His car regularly lifts a front wheel in the turns and I know he has some sort of concotion of heavy oils he puts in the shocks. I'm running cheap ($19) non-adjustable Monroes tube shocks in the rear that are pretty soft. My front shocks (Spax adjustable) are set at about "mid-firm". All my turns are on four wheels.
I think your shocks are responding too slowly in rebound. If I were you, I'd try something lighter, like motorcycle fork oil in the dampers and allow them to work a bit more.
The "sudden oversteer" you're getting may be due to shocks are aren't compliate enough too.
Also, one of our guys used the same MiniMania Panhard rod that you have. I can't recall why, but he took it off and put a different one on...I'd look at that too.
I am running one extra leaf in my rear and I notice my car is a bit tail-happy too (I've spun it a few times this year). One of my friends thinks that my car is too stiff and that the stock spring setup is just about perfect in terms of stiffness. He bases part of his opinion on information that the late Arthur Mallock has written (the guy who invented the "Mumford Link", popular in Euro-Spridget racers -> https://not2fast.wryday.com/chassis/mumford.shtml )
I'm running fairly moderate 400# springs in the front. I may return to the softer rear setup next year...It's my experience that Spridgets seem to work best with only moderately stiffer dampers and springs.
 
That cone was a pointer of some kind, I think ... I only hit 1 cone on my first run (none on any other runs ...) and it wasn't that one, it was just a little later in the turn in the picture (a bit too much speed with a tight turn into an off-camber finish) /ubbthreads/images/graemlins/smile.gif

As to weight transfer, Dave, I think you're assuming the car will lift the other wheel immediately upon addition of a rear bar. However, if the rear suspension allows too much roll, while the front allows significantly less, it will actually transfer weight to the rear (supposedly). This is what I suspect is happening. It is entirely possible that my rear shocks are too stiff, but I don't think that's the only answer. While softer shocks may reduce breakaway, they certainly arent going to put any meaningful weight on the front inside tire, even if the tire was actually on the ground. it would simply let the tire follow the ground a bit longer, with no load on it (meaning it doesn't actually provide any cornering force, despite the fact that it's touching) If the vehicle's center of mass remains closer to the centerline of the track, it will tend to transfer weight to the inside of the car. This indicates that instead of rolling over (picking up inside tires), it will tend to slide. Of course, this all depends on how much cornering the outside wheels provide, etc (and assumes the vehicle behaves as a block, not suspended by springs etc). However, this assumption is increasingly valid as we stiffen the roll-bars because of the reduced body roll. While the handling may indeed be strange, as Nial said, it will put the inside front tire down with a load on it, and will likely provide better grip right up until the car starts to lift both wheels at the same time.

Needless to say, I intend to test these theories extensively, hence why I would like to experiment with a mumford link (fully adjustable of course) so that I can change roll centers, rear bar stiffness, and even shock stiffness (with adjustable rear shocks) and compare times on the skidpad. That won't tell me how it behaves under more transient conditions, but it will tell me how many g's the car can pull in steady state, which would be a good start. I can then use that information to adjust for transient conditions to make the car more predictable -- i.e. less twitchy.
 
I had mine rip out from the bottom also. Since I had that issue and some ground clearence issues Ive mounted mine on top of the frame rail and reinforced the mounting points on top. Never had any issues ripping it off since its been on the top. I did find the next weakest with is the a-arm where the endlink attaches. I have not had any problems with that since reinforcing that as well.
 
"The exhaust manifold has been sand blasted and coated with a high temp coating."


What kind of a coating did you use and how has it held up?

Oh yea, one fine looking engine room.
 
By far the best handling sprite I have ever raced has a tiny 1/2 inch sway bar. I do have cars with much more bar under them but this bugeye I race performs better than any other sprite I have driven. The car came to me with this set-up from a good friend who has passed away. He raced his first sprite in 1959 and continued to race sprites till he died in 1993,as a result he knew far more than me. This was the last car he built. I am leaving it alone. It has made me re-think what I have been doing as far as sway bars on racecars.
I am beginning to think that all the 3/4" and up bars I have been using (and ripping up over stressed mounting points) are a waste. I think that you can get too much sway bar.
I am not saying that what is on your car is wrong. I am just making an observation as to things that are making me question my suspension ideas of the past. I am starting to think that at least for me after many years, maybe more is not always better.
 
[ QUOTE ]
"The exhaust manifold has been sand blasted and coated with a high temp coating."


What kind of a coating did you use and how has it held up?

Oh yea, one fine looking engine room.

[/ QUOTE ]

It is the High Temp Coating from Eastwood. It still looks today just as it did when it was painted.

https://www.eastwood.com/shopping/product...high+temp+paint

Also I have found that for intake manifolds if you sandblast them and then put on a clear powdercoat they will stay looking new for a long time too.
 
In addition to being quite large & attached to a frame section that was weakened by rust, you don't have any shaft collars to keep it centered...its probably shifting side-to-side because its too large...I just bought clamps for my 3/4 bar from McMaster-Carr....think their web site is https://www.mcmaster.com....then type collars in the search block...got mine overnight.
 
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