US Dollars
Lower the Classic VW Rear the Right Way
Measure in degrees, re-index the torsion bars, finish with the right shocks. Process — not parts — determines ride quality.
Set it in degrees, not inches
A swing axle moves in an arc
The wheel on a swing axle doesn't travel straight up and down. It swings in an arc, so a tape-measure ride height changes with tire size and offset. Camber angle doesn't. Measure it at the axle tube, the brake drum or the wheel; they're all connected, so any of them works.
Zero to about +2° of camber is considered stock ride height. Here's what the travel looks like on a 1960s swing axle car with stock spring plates and the torsion bar removed:
| Point in the travel | Camber | Shock length |
|---|---|---|
| Fully extended | 8° down | 16.5″ |
| Rubber bump stop starts working | 5° up | — |
| Spring plate hits the hard stop | 9° up | 10.5″ |
Why we skip drop plates
Drop spring plates are the quick way to lower the rear, and the one we tell clients to skip. The transaxle has an internal pivot point as well as the outer one. Drop plates only change the outer point. The inner joint still runs out of travel, and it hammers the transmission components every time it does.
| With 1.2″ drop plates | Camber | Shock length |
|---|---|---|
| Fully extended | 6° | 14″ |
| Fully compressed | 11° | 9.75″ |
The inner and outer spline trick
The torsion bar has 40 splines on its inner end and 44 on its outer end. VW did that on purpose. One inner spline moves the spring plate more than one outer spline, so moving one of each in opposite directions gives you a fine adjustment.
| Move | Change in spring plate angle |
|---|---|
| One inner spline (360° ÷ 40) | 9.0° |
| One outer spline (360° ÷ 44) | 8.2° |
| One inner + one outer, opposite directions | ≈ 0.8° |
That's roughly a 1/4″ change in ride height at a time. The factory service manual lists the install angle for stock bars (8.5° for 26 mm bars, for example). For other bar sizes, print the Sway-A-Way torsion chart.
Measure under load
Setting the spring plate angle on the bar is perfect for a new car with no wear. Real cars have relaxed torsion bars, and rarely evenly. Put a jack under the spring plate and take your degree reading just as it starts to lift the car.
Account for rake. The book angle assumes a level car. Either level it, or measure the frame tunnel as the car sits on stands and work it in.
| Example | Angle |
|---|---|
| Target (relative to the car) | 6° |
| Frame tunnel rake on stands | 3.5° |
| Spring plate reading to aim for | 2.5° down |
Re-index the spring plates
The parts that make it perfect
You can lower the rear with nothing but labor. To make it ride right, finish with these: