Rear Wheel Alignment on swing axle bugs

[Martin S.]

Talking to local wheel/suspension guru here in So. Ontario, Lanner told me the reason my lowered 68 doesn't go as straight as a stocker was that I needed to add toe out to the rear end. He said to push the axles back all the way in the slots and to grind them even longer if it's a really lowered car. I remember reading in the Berg bible the same thing but Gene didn't explain exactly how to do it, or how to measure it.
So I tied a string all the way around the car over the tires below the centerline and saw that the right rear had a tiny bit of toe in. I did what Lanner said and got 2 or 3 mm's movement to the rear on both sides. Driving it last night the steering felt lighter and car seemed to go a LOT straighter. Anybody else out there experiment with this? I can't figure out how to measure toe out at the rear, as the string only shows toe in - maybe a straight edge?

[brian e]

I just had a 4 wheel alignment done on my lowered baywindow.  It is IRS, but toe-in is toe-in.  I also noticed a huge difference in driving.  Even at 45mph the bus now goes straight as an arrow, and the rear stopped wandering.  Before at 65mph on the highway I had my hands full keeping it from wandering into the next lane.  Now I can take my hands off the wheel.  I was amazed.  Best $100 I have spent on the bus.   

I have done this a few times to check the rear toe.  Take 2 broom sticks, same length, and bungy cord one too each wheel.  Middle of the sticks right at the middle of the wheel front to back.  You might have to do it on the lower part of the tire so the stick is under your running board.  Make them parallel to the ground, then measure between the sticks in front of the tire (tape measure under the car) and the back of the sticks (tape measure under the rear bumper).  Get them as close as you can, and you will be good to go.  All the measurements have to be done at ride height. 

Brian

[Martin S.]

Hmmm, I have a 71 Bus with the wanderlust problem and I think it needs toe out too. Do you know what spec yours ended up at? I had mine checked years ago at a VW dealer and they said it was ok but I think it needs a different setting than the manual says. According to Berg the SA and IRS are totally different because the SA changes toe with the arc of the suspension travel and IRS does not have that problem. He wrote a page on SA and then at the end of that said that with IRS just use a toe in tool and set it. I don't have the book in front of me, but many people have it, it's this one... http://www.amazon.com/GB-801-Book-Technical-Articles/dp/B000JM8N6M/ref=sr_1_4?s=books&ie=UTF8&qid=1407364861&sr=1-4

[Sepi]

Talking to local wheel/suspension guru here in So. Ontario, Lanner told me the reason my lowered 68 doesn't go as straight as a stocker was that I needed to add toe out to the rear end. He said to push the axles back all the way in the slots and to grind them even longer if it's a really lowered car. I remember reading in the Berg bible the same thing but Gene didn't explain exactly how to do it, or how to measure it.
So I tied a string all the way around the car over the tires below the centerline and saw that the right rear had a tiny bit of toe in. I did what Lanner said and got 2 or 3 mm's movement to the rear on both sides. Driving it last night the steering felt lighter and car seemed to go a LOT straighter. Anybody else out there experiment with this? I can't figure out how to measure toe out at the rear, as the string only shows toe in - maybe a straight edge?

You cannot use a string if your front and rear track widhs are not the same. I have also used sticks, like Brian. Here is one typical debate of this topic, maybe there are some good advices

[Martin S.]

The string will show you what each side is relative to each other regardless of the track front and rear being different. The front and rear do have to be square with each other and Berg explained that process in detail in his tech article. An alignment tool (like the broomsticks) only works well at the front as the steering will center itself because of the caster working as you drive. In the rear you need to be able to find the toe angle of each wheel separately to be sure that the car won't steer one way or the other if weight is transferred to that wheel. Berg said they have to match or you can crash easier.

[Dougy Dee]

Measure from the centerline of your case and transmission to get a base dimension to measure rear toe. The broomsticks are an interesting addition.

[Martin S.]

That should work, measuring from the trans center-line out to the front of each broomstick!

[brian e]

But you would have to measure both ends of the broomstick.  Cant just measure the fronts and match them side to side.  The front of the stick must be very similar to the back of the stick. 

Measuring off the trans never occurred too me.  Good one!

Brian

[Jim Ratto]

Measure from the centerline of your case and transmission to get a base dimension to measure rear toe. The broomsticks are an interesting addition.

This is what I do, along with split line of case (in front of and behind deep sump) and measured center point between outer ends of lower control arms and lower shock mounts. I transfer marks to garage floor and measure outward and set up string lines parallel to these marks on floor. I then use vernier dial caliper to measure toe. Check out the HP Book, you need to know rolling radius in order to compute toe, dependent on tire size. The formula is in that book. Puhn is the author, I'm not referring to the HP Hot rod Vw book.