Bent my Weltmeister adj spring plate at the track

[Ho Hum 74]

Anyone ever heard of this happening? I bent the left spring plate rather badly at Gingerman (lot of hard right handers) this weekend.

There seemed to be too much bending moment on the plate where the adjuster screw meets the welded block. It warped that piece inwards. The suspension collapsed and the tire rubed pretty badly on the fender.

I took it to a local shop and they straightened it. 4 laps later it did the same thing. Not to lose an entire weekend of track time, I took it back and had them weld the two plates together. That did the trick and relieved the bending moment. I went hard at it for the rest of the weekend and no problems.

Seems like these are really soft and made out of a mild steel. I'm running 29mm torsion bars on a 2400# car.

Do you think I should ask for a replacement under warranty (if there is any?)

Tristan

[IROC]

Yikes!! I have to believe that something else is going on there to induce enough bending loads into your spring plate to cause that problem.

I have 29mm torsions on a 2350lb car with the Sway-A-Way adjustable spring plates (same ones?) and have put thousands of grueling track miles on them without anything like this occuring...

Mike

[Grady Clay]

Tristan,

Good for you!

You kept attacking the problem and ultimately found a weekend solution. That kind of perseverance is what makes racing (and much else in life) successful.

No, I wouldn’t ask for warranty – it’s a race part used while racing.

However, I would work with them to try and investigate the cause. Analyze the failure mode. Compare to the set-up on the other side. Look at all the possibilities; binding, incorrect assembly, another component loose/failing, materials failure, incorrect design, etc. They can (should) be able to tell you if this has or has not been reported before.

The goal is to find if there is a problem. If so, find a reasonable solution.

Some details that might help Pelican diagnosis:
What bushings on the spring plate?
What bushings on trailing arm (banana)?
What sway bar configuration?
What shocks?
What is the suspension travel before the rubber stops?
Any other mods?


There isn’t a part on a 911 that can’t be made stronger. The down-side is usually in weight penalty or cost. That part can be fabricated from forged Titanium but not much market at $100K. That part can be fabricated from larger dimension alloy steel but no one wants a 50# spring plate.

Best,
Grady

[JP911]

I recently faced the decision about factory vs. aftermarket adjustable spring plates. My local shop who does alot of race car prep strongly advised me to avoid the aftermarket spring plates. This must be one of the reasons why. Maybe now is a good time to find a set of factory adjustable spring plates.

[89911]

Seems odd. Mild steel or not, those are much thicker then the factory ones. One problem seen with there installation is that the incorrect spacing allows them to move independantly of each other, the adjusting screw then slipping off the adjusting mount. This is an installation problem. I've never had an issue in 4 years with my heavier 89 car. If these were that "mild", it would of surely come to light by now. Hope you get it cleared up.

[Formerly Steve Wilkinson]

Nobody ever accused Weltmeister of making high-quality stuff...

Stephan

[911pcars]

Before condemning the WMs, I suggest checking the rear end alignment. Maybe a bent control arm or something else is throwing off the geometry. I'm not aware of any history with the adjustable WM spring plates bending. The beefy camber and toe eccentric bolts clamp the two-piece spring and adjuster plates together making this a fairly strong piece.

Can you provide us with any pics?

Sherwood

[Ho Hum 74]

I can show you the now straightened and welded pieces!

I think the plate with the adjuster screw may have moved enough to provide an additional bending moment on the plate and that was enough to warp it.

Tristan

[H20911]

Pictures if you have them would be great. I would like to see the damage.

[katigbr]

My thinking is that either something is wrong with the rear ontrol arm or suspension geometry. I had a rather large contact with a retaining wall a few years ago and bent the torque tube and Sway-a-way springplate. I had the tube straightened and the springplate changed. I later realized that I had also bent the trailing arm enough to pull the springplate arm away from the fixed adjuster piece enough to worry me about "slipping" off the adjuster bolt in higher-G curves.

Did you notice any abnormal gap between the springplate components after bolting them onto the tub? Any history banging that tire against curbs or anything?


Rick

[Ho Hum 74]

Did you notice any abnormal gap between the springplate components after bolting them onto the tub? Any history banging that tire against curbs or anything?

I noticed this AFTER the damage had occured but not before unfortunately. The other side is very flush. I think this is correct: the plates moved away from eachother enough to cause the bending moment to increase beyond the limits of the material.

Tristan

[fredmeister]

You may have to show pictures before we can come up with ideas on what is going on. The design of the plates do not make the moment on the small rectangular pad used for height adjustment welded to the outer plate that severe. In fact as the gap opens between the inner and outer plate form misalignment described by 89911, the moment on that rectangular piece gets less. The spring plate's function is to allow warping or a slight twist as camber changes with suspension travel, but to be very stiff fore aft direction only. You may have bent banana arms or issues with the inner bushing where it attaches to the torque tube that causes it to twist so bad. Your camber change would be horrendous as suspension travels up and down.

[Ho Hum 74]

I don't have pictures since it is now straight and the two plates are welded together. The bushings had to be machined out to fit. Actually, I'm amazed at the absolutely poor quality of these expensive parts. $400 for a kit where the bushings don't fit and the tubes have never been test fitted with torsion bars is unacceptable. I spent many many hrs filing the teeth and having the bushings machined. I'd never buy another product from them again.

[89911]

Originally posted by Ho Hum 74
I don't have pictures since it is now straight and the two plates are welded together. The bushings had to be machined out to fit. Actually, I'm amazed at the absolutely poor quality of these expensive parts. $400 for a kit where the bushings don't fit and the tubes have never been test fitted with torsion bars is unacceptable. I spent many many hrs filing the teeth and having the bushings machined. I'd never buy another product from them again.

Not to argue for Weltmeister, but it would be damn near impossible to make a bushing that fit every car perfectly. Even the brass ones being sold use shims to get the fit correct. I've done it twice for my brother and mine car, both for the spring plate and the a-arms. It's a pain, but after a few its not that bad.

[Randy Webb]

The factory part is stronger, cheaper (used) and safer. It is just a bit more work to adjust. I don't understand why people buy these things....

[Zeke]

I recently had some experience with a bent spring plate. I bought it that way when the seller failed to tell me about it. No names, I'm past the issue.

But, it did happen and I saw the results. Now, my thinking is that the bushings were at fault. Again, it wasn't on my car when it bent, so all circumstances are not known.
I sent them on to another person who can fabricate and mke something out of the spline parts that contain the adjuster screw.

One is not going to adjust the things that often. The way they slip around on each other when lifting the car and whatnot, I would think that bolting them together after the adjustment is made would be the hot tip. This would prevent some of the problems mentioned.

I have a brand new set now and I'm going to go out and look at them with that idea. I might just drill a 7/16ths hole and make a slot out of one side with a file.

[jpahemi]

Hello,
With apparent poor quality of Weltmeister and Sway Away, why don't more people use Sanders bars?? I just purchased a set of new factory spring plates and they seem to be shot peened; does anyone know if this is standard?
Regards,
J.P.

[yelcab1]

I was able to tell just by the sound alone that the valet parking boy was pulling up in my car.