73 super beetle needs new suspension

[barefootskater1200]

Link to your document? I can't seem to find it.

[raygreenwood]

Go the the 411/412 forum. First post is mine....411/412 strut modification document. Halfway down my post is a link to a, dropbox. Let me know if you have any issues. Its a, word document of about 120 pages. Ray

[barefootskater1200]

I'm looking at the front end kit on topline racing. It says that the control arm bushings are urethane.
I noticed that you said to stay away from urethane.

I like the kit because it seems to have everything I need apart from shock inserts. Also it's fairly inexpensive.

Is it a bad idea thoug? I don't understand the urethane argument (haven't read the whole 411/412 document yet) and I want to do this right but budget is an issue...

[raygreenwood]

The issue with urethanes are these:
Polyurethanes are awesome compounds. Outside of just a few actual compounding resin methods….there are and endless number of variations with additives…without….with special modifiers etc.
But they all have some of the same issues.

Your factory stock control arm bushings….and virtually all bushings in your suspension…were all made of synthetic rubber. They are generally between 50-55 durometer in hardness. They age really well (if they are well made)…especially in large cross section bushings…because the vast majority of the rubber in the bushings are inside of the cross section and not on the outside exposed to the elements. So 10-30 years items like control arm bushings can still function pretty well even though the outside has cracks and abrasion.

The differences in urethane is that the durometer of urethane is not a 1:1 ratio with natural or synthetic rubber.
Urethanes are also measured in their elasticity and maximum coefficient of elongation (some refer to this as rebound)…..which refers to how good of a spring material or elastomer it is.
In this respect…urethane is superior to rubber. When urethane is being used as a spring…a 50 durometer urethane will have a 3x the spring loading ability as say buna N rubber. However…this same ability is a problem….because if you used a 50 durometer urethane bushing on your control arms….you would have horrible steering and probably end up wrecking the car…because ….as I noted…capabilities are not 1:1 equal……at 50 durometer most urethanes are very, very elastic and tend to more “jello” like.
So….most suspension bushings are made of 75-80 durometer urethane to give similar stiffness as synthetic rubber. The problem is that they are very hard….especially at that durometer …which will give about 5x the spring rebound capability as rubber.

Add to this that even the urethanes molded with special lubricants get squeaky in hot dry weather….and add to that….urethanes naturally continue to chemically harden at a rate of 3-5% per year. Plus..they are very temperature dependent. They get harder in cold weather.
In general urethane suspension components exist at all….. because they work very well especially in cars that are very heavy and have very solid parts that cannot be easily broken by excessive spring compressibility of the bushing……like big Detroit cars…….our cars with lighter weights and thinner parts can suffer from excessively hard suspension bushings.
….and the fact that they ARE an upgrade in stiffness that cannot be had affordably any other way for older and non-stock cars because urethane is cheap and easy to cast with low tech molds as compared to synthetic rubber which is a pressure casting technique at the lowest and injection molded at the highest quality.
In my opinion…urethane suspension parts are kind of a mid-grade….mid-level performance mod. You will need to keep an eye on them and keep them lubed because they will harden up and start breaking things in about three years.

I say mid-level/mid-grade….because the serious performance guys simply move to Delrin control arm bushings…which you can make on a drill press with some elbow grease for about $20 in material from McMaster Carr.
I use urethane center sway bar bushings…because they are tough, cheap, fit well, perform well and even the squeakiness is small for the upgrade.
I used to use them for outer sway bar link bushings and radius arm donuts. I stopped that when twice in 6 months the outer link bushings SNAPPED…yes…SNAPPED the outer link bolt on the rear of my 412. That was a 10mm class 10.9 bolt! The first one I put off to a possible cracked bolt. The second one I could not ignore. It was the new bolt…top quality and I almost rolled the car.
The radius arm donuts literally shattered the steel mounting eye on my subframe when I went over a bump in freezing weather one morning. Barely got home.
If you go to Delrin in the control arm bushings….a lot stiffer than urethane anyway….it makes the track control so steady….that with other normal mods like the bronze idler bushing…..you will have about a a 50% upgrade in handling…even while keeping normal rubber strut bushings and sway bar bushings.
Urethane is not bad….it just harder than you need…is not a direct stock replacement….and ages poorly.
Ray

By the way...you can get OE German from CIP1 and others for about $20 each. Actually for the control arm bushings....meaning the pivot points...urethane...IF they are well made and fit well....should be fine. They dont use much spring action in this position. However...you WILL be redoing these because of how hard they will get in just a few years.

My other issue with how most bushings that have a flange at one or both ends are made...when they are urethane...is that they are two piece split bushings with a steel or bronze tube going through the center. This causes flexing about the split in the center. Sometimes its an issue...sometimes not.
Though its harder to install....a single piece center bushing with outside flange washers is a better performing option in any material. And...as the flange washers wear which is the first part of any control arm bushing that wears...you can replace them for cheap without pressing in new bushings.

Its hard to complain about Topline...because they do a great job and make great products....but that does not mean that urethane is the best choice or highest tech of materials.

Also...I take issue with one of their claims. Overly soft stock bushings are NOT the cause of the "shimmies"....they just allow it to get worse as they age.

The cause of the "shimmies" in both first 411 cars...and later Super beetles.....we had it in the type 4 cars before the super beetle even existed.....is a stack-up of issues.

The primary two components that start the shimmies are:
1. the really shitty idler arm bushing design
2. The really long, vibration prone centerlink

NOTE: long suspension arms of any type magnify vibration and movement through leverage.

The poor vibration control set up by these two parts....was magnified by the kind of crappy and vibration prone upper strut bushing design.

All of this was made worse by age....and hugely so by incorrect alignment techniques by most shops. Yes...as teh bushings aged and got worn...they allowed all rattles and vibrations to magnify...which is why just replacing the bushings seems to really get rid of the shimmies....but not totally.

Its a combination of vibration and vertical oscillation in the strut column. Also...90% of these cars by this age have spread spots in the wheels that are generally not detected at tire balance because you really have too have the tire off to measure them.....and the suspension is incapable of damping that problem.

[Piledriver]

The graphite/moly loaded Prothane bushings I have had in my squares rear end for the last ~60K miles haven't squeaked yet, nor been relubed.

Hve had no noises from other bushings made from same material, but I don't drive the Cabby and Jetta nearly as much as the square. (I don't buy the red ones as they are not self lubricating or take external lubrication well)

I also have installed urethane upper strut bushings and control arm bushings in the Mk4 TDi that literally transformed the cars handling by keeping the suspension pivot points ~in one place, previously everything could and did move up to 3/4" at the pivots.
(the stock and esp aftermarket replacements are like marshmallows with a 4000 lb car on them, although the HD rubber Audi TT factory lower arm bushings are the preferred parts apparently)

In many applications, urethane (at least the black moly/graphite loaded stuff) is pretty much a win with few issues.
As it ages, it gets harder... but again, not an issue in most applications.

If any shear forces are in effect it can have a short, dismal life but they still sell it in those apps to folks who don't know better.
(vw mk1/2/(3?) front lower control arm bushing with offset pivot angles as an example)

Rubber works well in shear. Urethane fares poorly.
(think motor mounts--- I have seen urethane T1 units (designed like factory rubber ones) fall apart in a few months, it's simply the wrong material for the design, it only really works well in compression)

[raygreenwood]

Exactly well put pile...and kind of what I was getting at. The right material in the right place...shear or overly hard compression is not the right place for urethane.

I have not had a chance to use any of the graphite filled parts yet. Glad to hear they are working well.

If I could find graphite replacement strut bushing donuts for late model super I would try them in my 412. Ray

[Piledriver]

Energy Suspension (who sell Prothane parts fro many apps) do not list the strut mounts, but it would not surprise me if some other vehicle had a compatible setup.

Thought:
I can't remember how the Mk1 strut mounts are in detail, they may share some design elements with the SB as production overlapped.

I have been seriously considering converting my Mk1 to the MK3/4 upper strut mounts, including welding in the required new top of the strut tower. The factory strut mounts would probably be fine on the much lighter Mk1 (or esp a T4 or super) and its a better design overall, and ~infinitely more pothole resistant.

Its smaller>= diameter vs. the original setup on a super, not sure if there's vertical room on a 411/412.

[raygreenwood]

Energy Suspension (who sell Prothane parts fro many apps) do not list the strut mounts, but it would not surprise me if some other vehicle had a compatible setup.

Thought:
I can't remember how the Mk1 strut mounts are in detail, they may share some design elements with the SB as production overlapped.

I have been seriously considering converting my Mk1 to the MK3/4 upper strut mounts, including welding in the required new top of the strut tower. The factory strut mounts would probably be fine on the much lighter Mk1 (or esp a T4 or super) and its a better design overall, and ~infinitely more pothole resistant.

Its smaller>= diameter vs. the original setup on a super, not sure if there's vertical room on a 411/412.

I "think" the Mk1 is close enough in donut, size that it may be adaptable. The bearing cartridge is very close.

Basically what I have done kn my 412 is graft in the guts from later super two part strut bushing (where the donut and bearing, are, seperate parts) and then took out all the slack areas and added UHMW thrust bearings.

Its, very close in technology now to the mk3 in the strut bearing assembly. I finally cut plates from 1/4" steel and welded in strut bushing cups from 74-79 super beetle.
Its tight tight tight now. I will have the front end back on the ground by end of july. Ray