Swingaxle suspension data, and how to set ride height

[modok]

I finally got my NEW 26mm swayaway torsion bars (long story), and so while my 1960 bug was apart I went ahead and took some measurements on the suspension travel.
To be accurate, it is a 1960 chassis with a 1968 transmission, 1962 spring plates and type-3 drum brakes, but far as i know all the 60's bugs are very much the same as far as this is concerned.

The wheel of a swingaxle doesn't travel anywhere near straight up and down, but rather travels in an arc.
Therefore actual ride height measurements are difficult, and also they change with the size and offset of the tire.
SO, I found it is easiest to just measure the travel and ride height in degrees of camber. The angle can be measured at the axle tube or the brake drum or the wheel, they are all connected together so it doesn't matter.

Zero degrees camber or perhaps up to 2 positive camber is usually considered the "stock" ride height.

The axle nut travels about one inch in 2.2 degrees.

With the torsion bar removed, but all else assembled, I measured the travel.

Extended: 8 degrees down, shock length 16.5"
When rubber bump stop comes into action: 5 deg up
When the spring plate hits the hard stop:9 degrees up, shock length 10.5"

Observations: I had been driving around at 3 degrees negative camber for a few years, the rubber bump stops and brackets seem to be in good shape. The top of the spring plate shows evidence of hitting the hard stop quite often. Nice powdercoating has been pounded off!

[modok]

I have always wondered how much the UP travel can be increased.

So, I then put on these "complimentary" special spring plates that go around the hard bump stop. This is all the way up, note the "hard stop" is still nowhere near hitting the spring plate.

This allowed it to travel up another 2 degrees, however it seems that this is all the travel the transmission allows, at this point the internal joint runs out of travel. I jacked it up a bit more but the engine started twisting
I tried the tire on it and it DID clear everything even at 11 degrees up.
So, these 1.2" lowering spring plates changed the travel thus:
Fully extended; 6 degrees, shock length 14"
Fully compressed; 11 degrees, shock length 9 3/4

[Boolean]

Excellent writeup! We as a community often do these things ourselves and think that nobody else cares, but simple info like this is valuable.
Perhaps some measurement of possible toe adjustments at extreme up positions would be next?
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Build thread here:
http://www.thesamba.com/vw/forum/viewtopic.php?t=529379

[modok]

So, the answer, in my case at least, is there is 7/8" inch of UP suspension travel that I could gain by notching the spring plate.
Of course, I don't want to break the side covers off the transmission, so I need a hard stop to hit before that. So maybe I could gain a half inch?? Not worth it IMO.
After all, with these stronger springs I should be hitting the hard stops only rarely anyhow, that is after all.... the point.

As far as the DOWN travel, I would like to limit this to about 5 or 6 degrees.
In the past I had limit straps, but they rotted, so then I had limit CHIANS but they are too harsh, so I think I will go back to how VW did it.
i added a re-enforcement bracket to the down stop and built it up with weld so it stops at 5 degrees droop. With the bigger torsion bars it won't hit the down stop with as much force, so I expect this will hold up.

[modok]

[modok]

I will try to explain how to set the torsion bar.
The inner side has less splines than the outer. This means that if you move an inner spline, it changes it MORE than if you move an outer spline.
By moving one outer and one inner, the ride height can be adjusted in about 1/4 inch increments.
So, first off you must make sure the torsion bars will go by hand into the plate and car, otherwise it will be hell to do this.

There are four different rubber bushings, you need one of each, they have thicker side that is supposed to go UP, and two different hole sizes for inner and outer. It can be difficult to work them into place, i have a solution, lube them with silicone oil. You all know what happens when you get grease or engine oil on rubber...... but this oil will not harm it. The silicone spray may work, but I like to use thicker stuff. Went through a little bottle of some stuff that was for lubing gutter seals, now I refilled that with silicone vaccum pump oil, I think heavy shock oil is similar also.

So how to get them at the right angle? (height)
Now, in the past I have tried to just do this with a tape measure, BUT, when the spring plate is not all the way in place it wiggles around and makes this impractical. Better to go by angle, using the angle finder thingy pictured above.
The service manuals list the angle they are supposed to be installed at. Sway-a-way has the info for the other sizes of torsion bar.
Print this out!
http://www.swayaway.com/techroom_vwguides.php

So, in my case it says 8.5 degrees for the 26mm bars. I want to go a bit lower, so I will try 6 degrees.
This angle is with the car level, so you either have to level the car, or just measure whatever angle it's sitting at and figure it in.

I go in and measure the angle of the frame tunnel as the car sits on the jackstands..... 3.5 degrees rake........ 6 minus 3.5.... So I want the spring plates to measure 2.5 degrees down.....get it?

So just stick the torsion bar in there, and put the lubed rubber thingy on the plate, and stick the plate partway, on close to where it should be and measure the angle.

Of course it will be way off, take the plate off again and pull the torsion bar out just enough to be free of the splines, rotate it a spline or two the same direction you want the spring plate to go, and put it back in, then put the plate on again and re-measure.

Once it is where you want it, push it on as far as it will go, then take a jack and raise the spring plate up over the lower stop. Sometimes the car is not heavy enough so you have to use a special tool or have bubba sit on the rear bumper. At this point I like to take a 2x4 and a sledge hammer and push the spring plate the rest of the way in. It is also possible to PULL it on with the cover, but I don't want to bend the cover.

I managed to get it to 2.5 degrees, (which is actually 6 relative to the car), just like I wanted.
I forget why i put the cover on, didn't need to yet.

Easy job with practice

[modok]

Sway-away Link disappeared!!, oh well it's still in wayback machine
https://web.archive.org/web/20130404012135/http://www.swayaway.com/TechRoom_VWguides.php

BTW, over a year daily driving almost no sag. Maybe a half inch.
Also, strong torsion bars and stronger shocks is good, gas-adjusts too bouncy!! bilstiens just right

[Dale M.]

Am I to believe you ditched the complimentary spring plates?

Care to state why?

Dale
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“Fear The Government That Wants To Take Your Guns" - Thomas Jefferson.

"Kellison Sand Piper Roadster" For Street & Show.
"Joe Pody Sandrover" Buggy with 2180 for Autocross (Sold)
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All suggestions and advice are purely my own opinion. You are free to ignore them if you wish ...

[modok]

The "drop' spring plates were used to see how far the axle can swing past the hard up-stop. Nothing more, nothing less.

[57BLITZ]

[modok]

That is a good question, I do not know!
I wish I had checked that a few weeks ago when rebuilding the transmission, but there just wasn't time. This is the only swigaxle VW I own, and also my daily driver!!

[Airkewld]

[chrisflstf]

[Airkewld]

[57BLITZ]

[modok]

[Airkewld]

[modok]

[modok]

[EVfun]

By request I'm adding some of my measurements and observations to this thread. This is mostly a quote from here.

I measured the available axle travel range on a '67 transaxle (long axle, short spline) on my shop floor. It was a rebuild and internally has 40 horse gear ratios except for 4th gear is the late 0.93. The case was factory made for the 130 tooth flywheel, the side covers are stock VW, not sure what year used. The transaxle has 13 degrees of range up from level.

If your measurements where done in a vehicle then this difference makes sense. Part of the upward movement in the vehicle is used up swinging the axle forward. While I don't think I've seen a swing axle Bug lowered to the point of -9 degrees camber if the spring plate is cut to allow the suspension to travel past -11 degrees of camber then it should try to go there on the first hard bump. That is why I'm surprised those extreme lowered Bugs with notched (or offset design) spring plates don't destroy the rear suspension at the transaxle even faster than they seem to do.

Thank you Modok for determining that 1 inch is about 2.2 degrees with a short axle Bug. That, plus -9 degrees being the hard stop, allows calculating what is reasonable. If one wants to replace tires often they could run at about -4.5 degrees and have reasonable suspension travel (about 2 inches up.) That is about 2.5 inches below stock, stock being around 1 degree positive for later swing axle Bugs. Notching the spring plates just slightly to respect the stock stop would increase to about 3.375 inches while retaining 2 inches upward travel (I used that number as it happens to be the minimum legal upward suspension travel in WA, though they don't inspect so they would never know.) To go lower than that in a swing axle Bug one really needs to raise the transaxle.

The axles have 40 inner splines and 44 outer splines. This seems like a good place to repost this:

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