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Max Welton
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Joined: May 19, 2003
Posts: 10972
Location: Black Forest, CO
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 Posted: Tue Apr 29, 2025 3:02 pm Post subject: Wind sensitivity |
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It's nice and breezy here today so I've been working on my cars sensitivity issues. 
The car tracks straight in no/low wind situations. But with a side wind it's a little twitchy.
The car is a 67 Fasty (swing axle) with 205x65/15s. Front wheels are 4.5" mangles. Rear wheels are 5.5" bug wheels.
The rear alignment was done at the local Porsche dealership and done again after I installed a new (VWNOS) steering box. All consumable suspension items (shocks, bushings, tie-rod ends) are new
My old 68 squareback running the same sized tires on 4.5" wheels was pretty stable in the wind.
I found this old thread on the topic. Not much help.
https://www.thesamba.com/vw/forum/viewtopic.php?t=120798
I'm running 30 psi in the back and normally run 20 in the front. I tried airing the fronts up to 30 today, but it seemed a little more stable at 20 psi.
With the larger tire up front should I be thinking about a touch more toe-in up front?
Max
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1967 Type-3 Fastback
Under the Knife https://shoptalkforums.com/viewtopic.php?f=24&t=151582
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jaransonT3
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Joined: January 01, 2005
Posts: 1308
Location: Dearborn, MI
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| Posted: Tue Apr 29, 2025 3:51 pm Post subject: Re: Wind sensitivity |
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Air pressure is a big influence on this wind stability. I run 18 psi in the front and 28 psi in the rear of both my 66 Square and Jill's 67 Type 34 Ghia. Both are running 175/55R15 in the front. Sophy is running 205/55R16 in the rear and the Ghia has 195/55R15 in the rear.
Both are lowered for what that is worth.
Running 28-30 psi in the front will normally make it super twitchy.
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'66 Square
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KTPhil 
Samba Member
Joined: April 06, 2006
Posts: 35706
Location: Conejo Valley, CA
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| Posted: Tue Apr 29, 2025 4:29 pm Post subject: Re: Wind sensitivity |
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Some generic advice and observations...
Crosswinds want to push the front sideways more than the rear, due to the rear weight bias. Thinner front tires will make this effect worse. Higher front tire pressure will also make it worse.
Swing axle cars like a little rear toe-OUT. The spec varies, but most have it neutral or slightly toed out. It doesn't take much, but it helps it self-correct slightly.
Making sure the steering gear is centered, and taking play out correctly (even on a new box) helps maintain control.
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Max Welton
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Joined: May 19, 2003
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Location: Black Forest, CO
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Bobnotch
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Joined: July 06, 2003
Posts: 23288
Location: Kimball, Mi
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| Posted: Wed Apr 30, 2025 12:34 pm Post subject: Re: Wind sensitivity |
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| jaransonT3 wrote: |
Air pressure is a big influence on this wind stability.
Running 28-30 psi in the front will normally make it super twitchy. |
Ran into that with my T-34 right after I had new tires installed. The tire shop pumped them up to 32 psi, and I forgot to check the tire pressures before my test drive. Like to scare the crap out of me, as it was all over the road. Got back and dropped them to 18 front and 28 rear. Drove like a new car after that. I should have known better, as I keep my Notch at those same pressures with 195-60-15's front and 205-65-15's rear, and it doesn't wander. It just rides better at those pressures too (the tires seem to have a little more give in the sidewall).
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Bob 65 Notch S with Sunroof
71 Notch ...aka Krunchy; build pics here;
http://www.thesamba.com/vw/forum/viewtopic.php?t=249390 -been busy working
64 T-34 Ghia...aka Wolfie, under construction... http://www.thesamba.com/vw/forum/viewtopic.php?t=412120
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raygreenwood
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Joined: November 24, 2008
Posts: 23020
Location: Oklahoma City
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| Posted: Wed Apr 30, 2025 8:28 pm Post subject: Re: Wind sensitivity |
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All of the above.....plus...not enough castor angle makes it sensitive to side winds and catching cracks and following them (called tram-lining).
Ray |
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Bobnotch
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Joined: July 06, 2003
Posts: 23288
Location: Kimball, Mi
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| Posted: Thu May 01, 2025 11:47 am Post subject: Re: Wind sensitivity |
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| raygreenwood wrote: |
All of the above.....plus...not enough castor angle makes it sensitive to side winds and catching cracks and following them (called tram-lining).
Ray |
Problem is you can't adjust the caster in a type 3. That angle is built into the frame head. VW did offer thicker rubber beam bushings for the earlier cars, then just switched to using the thicker bushings for all cars. I think this change happened in 1965, or 66.
My T-34 had Kumho tires on it, and would wander on grooved concrete, due to the lines carved in it. It was the only car I had that would do that too.
_________________
Bob 65 Notch S with Sunroof
71 Notch ...aka Krunchy; build pics here;
http://www.thesamba.com/vw/forum/viewtopic.php?t=249390 -been busy working
64 T-34 Ghia...aka Wolfie, under construction... http://www.thesamba.com/vw/forum/viewtopic.php?t=412120
| Tram wrote: |
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| Tram wrote: |
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Max Welton
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Joined: May 19, 2003
Posts: 10972
Location: Black Forest, CO
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Multi69s
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Joined: January 24, 2006
Posts: 5537
Location: Lefty, CA
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| Posted: Mon May 26, 2025 1:06 am Post subject: Re: Wind sensitivity |
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Ok, I am a little confused with some of the information, especially rear toe. From what I have read, and one experience I had, I was taught to believe that you wanted toe in at the rear for straight line stability. My personal experience may mean zilch because of the vehicle, but here it is:
When I was 16 (in the 80s) I had my own desert rail. We got the frame, a old swing axle single seat race car for free, and widened it into a two seater, Stripped a couple of wrecked VWs for all the need parts. My dad hopped up a 1600 to within an inch of its life, and turned me loose with it.
The first trip out was in Jaw Bone Canyon in the Mojave desert. I took it out on some perfectically flat dirt roads. When I got up to about 50 (guessing) The rear in had a mind of its own. Basically I was fishtailing down perfectly straight roads. My 16 year old brain knew this was wrong, so I took it back to camp, told my dad, and he hopped in it for a very quick ride. Came back and said there is toe out in the rear. Grabbed a tape measure added some positive toe and it was a totally different car.
Now we may be talking about apples and oranges. With a swing axle off road vehicle on flat roads the camber is going to be different then a road car. On the off road side, you will be running on the outer edge of the tire. However, with a road car the tire may run vertical or run on the inner edge. Maybe this changes the picture, but I was always taught the positive rear tow gave you more straight line stability.
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69 road Bug 2110
73 Squareback - 2L, T4, Automatic W/ AC
Gone, but many fond memories 69 Baja Bug 2010 - 5 Rib Bus Transaxle
Gone but not forgotten 72 Baja Bug 2010
My builds
T4 into Squareback http://www.thesamba.com/vw/forum/viewtopic.php?t=458944&highlight=
Auto Trans Rebuild http://www.thesamba.com/vw/forum/viewtopic.php?t=516066&highlight=
AC in Squareback https://www.thesamba.com/vw/forum/viewtopic.php?t=...highlight= |
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raygreenwood
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Joined: November 24, 2008
Posts: 23020
Location: Oklahoma City
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| Posted: Mon May 26, 2025 7:39 am Post subject: Re: Wind sensitivity |
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| Multi69s wrote: |
Ok, I am a little confused with some of the information, especially rear toe. From what I have read, and one experience I had, I was taught to believe that you wanted toe in at the rear for straight line stability. My personal experience may mean zilch because of the vehicle, but here it is:
When I was 16 (in the 80s) I had my own desert rail. We got the frame, a old swing axle single seat race car for free, and widened it into a two seater, Stripped a couple of wrecked VWs for all the need parts. My dad hopped up a 1600 to within an inch of its life, and turned me loose with it.
The first trip out was in Jaw Bone Canyon in the Mojave desert. I took it out on some perfectically flat dirt roads. When I got up to about 50 (guessing) The rear in had a mind of its own. Basically I was fishtailing down perfectly straight roads. My 16 year old brain knew this was wrong, so I took it back to camp, told my dad, and he hopped in it for a very quick ride. Came back and said there is toe out in the rear. Grabbed a tape measure added some positive toe and it was a totally different car.
Now we may be talking about apples and oranges. With a swing axle off road vehicle on flat roads the camber is going to be different then a road car. On the off road side, you will be running on the outer edge of the tire. However, with a road car the tire may run vertical or run on the inner edge. Maybe this changes the picture, but I was always taught the positive rear tow gave you more straight line stability. |
I was waiting for someone else to see the same thing. I was wondering if there was something i was missing.....like is it different on a swing axle.
I know on IRS...you need a small EXACT amount of EQUAL toe-in for rear stability.
To understand why you need to understand why you need toe-in anywhere in the vehicle. As the car is pushing forward against the friction generated between the tire and the pavement.....that friction forces the tires OUTWARD. It flexes whatever rubber bushings are in the system and flexes any longer suspension members that are subject to the leverage (not sure if that last one is an issue on type 3 but it is on type 4).
The wider the tire, the more road friction and the more spread....and the more toe-in required.
Now, that said......at very LOW speeds actual straight line or toe-out makes very good stability. But once you get up over a certain speeds (varies a little from car to car and tire to tire).....and the road friction gets high enough to start spreading the tires outward....the car....whether this is front or rear....will start alternately steering outward from side to side. I used to call it "swooping".....you get a quick pull to one direction and the to the other.
If it's the rear end with too much toe out....it feels like a a rapid sway. It's also very dangerous. Ray |
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Max Welton
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Location: Black Forest, CO
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ALLWAGONS
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Joined: June 03, 2000
Posts: 4583
Location: Pasadena CA/DTLA soon China
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| Posted: Mon May 26, 2025 8:30 am Post subject: Re: Wind sensitivity |
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Wind sensitivity? It’s an old VW. Just enjoy the engine purrr and the wind on your face. Want wind sensibility? Try driving a stock height Westy on the 101 fwy by the ocean during winter winds. It was fun getting lane changed involuntarily! I enjoyed the panic from my passengers.
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Max Welton
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Posts: 10972
Location: Black Forest, CO
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Bobnotch
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Posts: 23288
Location: Kimball, Mi
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| Posted: Mon May 26, 2025 12:23 pm Post subject: Re: Wind sensitivity |
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I think I remember reading in Bentley that VW wanted 1 minute+-30degrees of toe in for the rear. I'm not sure how much that actually is though, as it could be 1/16th or 3/32nds, or anywhere in between. I know up front I use between 1/16th and 1/8th toe in for my own car. I've never checked the rear, as I know the bushings are probably worn, and I've never unbolted the spring plates on it.
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Bob 65 Notch S with Sunroof
71 Notch ...aka Krunchy; build pics here;
http://www.thesamba.com/vw/forum/viewtopic.php?t=249390 -been busy working
64 T-34 Ghia...aka Wolfie, under construction... http://www.thesamba.com/vw/forum/viewtopic.php?t=412120
| Tram wrote: |
| "Friends are God's way of apologizing for relatives." |
| Tram wrote: |
| People keep confusing "restored" and "restroyed". |
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raygreenwood
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Joined: November 24, 2008
Posts: 23020
Location: Oklahoma City
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| Posted: Tue May 27, 2025 4:32 pm Post subject: Re: Wind sensitivity |
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| Bobnotch wrote: |
| I think I remember reading in Bentley that VW wanted 1 minute+-30degrees of toe in for the rear. I'm not sure how much that actually is though, as it could be 1/16th or 3/32nds, or anywhere in between. I know up front I use between 1/16th and 1/8th toe in for my own car. I've never checked the rear, as I know the bushings are probably worn, and I've never unbolted the spring plates on it. |
Last week or so when I commented that castor is a big problem with wind sensitivity....yes...I know that type 3 has no castor adjustment. For that matter, I don't think any of the acvw have adjustable castor (neither DID my type 4 until I installed it)....but yes, you can unbolt the beam mounting points and install shims.
That being said, from the factory, type 3s SHOULD have more built in castor than any other acvw....in fact its about 4° vs 3° for type 2 and about 2° for type 1 and even a less for my type 4 at 1° 10'....which is horrendous in cross winds.
But from the factory the type 3 had the most castor....you can take away that the castor is critical for type 3.
So what happens if you have LESS castor than what is spec'd by factory? How would that happen?
1. If the beam were removed or replaced and put back on.....not perfectly....it could happen.
2. The most common causes is this....if the rear of the car is jacked/lifted up...say by either a larger diameter tire or higher profile tire.....or by changing the spline position on the rear beam and lifting the rear....or by changing the spline position, wheel diameter or profile on the front....making the front lower than the rear.....this induces a forward rake which reduces axis of inclination.....which reduces static castor....which makes the steering more sensitive to wind wander and tram-lining.
Ray |
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Multi69s
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Posts: 5537
Location: Lefty, CA
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| Posted: Wed May 28, 2025 7:36 pm Post subject: Re: Wind sensitivity |
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| raygreenwood wrote: |
| Bobnotch wrote: |
| I think I remember reading in Bentley that VW wanted 1 minute+-30degrees of toe in for the rear. I'm not sure how much that actually is though, as it could be 1/16th or 3/32nds, or anywhere in between. I know up front I use between 1/16th and 1/8th toe in for my own car. I've never checked the rear, as I know the bushings are probably worn, and I've never unbolted the spring plates on it. |
Last week or so when I commented that castor is a big problem with wind sensitivity....yes...I know that type 3 has no castor adjustment. For that matter, I don't think any of the acvw have adjustable castor (neither DID my type 4 until I installed it)....but yes, you can unbolt the beam mounting points and install shims.
That being said, from the factory, type 3s SHOULD have more built in castor than any other acvw....in fact its about 4° vs 3° for type 2 and about 2° for type 1 and even a less for my type 4 at 1° 10'....which is horrendous in cross winds.
But from the factory the type 3 had the most castor....you can take away that the castor is critical for type 3.
So what happens if you have LESS castor than what is spec'd by factory? How would that happen?
1. If the beam were removed or replaced and put back on.....not perfectly....it could happen.
2. The most common causes is this....if the rear of the car is jacked/lifted up...say by either a larger diameter tire or higher profile tire.....or by changing the spline position on the rear beam and lifting the rear....or by changing the spline position, wheel diameter or profile on the front....making the front lower than the rear.....this induces a forward rake which reduces axis of inclination.....which reduces static castor....which makes the steering more sensitive to wind wander and tram-lining.
Ray |
Ray,
You jogged my memory. On out type 1s we almost always put in caster shims for high speed stability and cross wind driving. Max you think your car reacts to wind, try a bug, with a bike rack and bikes on top. That is down right scary. So caster shims are very common for Type 1s, but I couldn't find any for type 3s. If I was having your issues, I would probably make a set, I don't think it would be too hard. Here is a video that does a pretty good job of explaining it. It is on Type 1s, but the principles are the same.
https://www.youtube.com/watch?v=J4XRDZQsqDs
_________________
69 road Bug 2110
73 Squareback - 2L, T4, Automatic W/ AC
Gone, but many fond memories 69 Baja Bug 2010 - 5 Rib Bus Transaxle
Gone but not forgotten 72 Baja Bug 2010
My builds
T4 into Squareback http://www.thesamba.com/vw/forum/viewtopic.php?t=458944&highlight=
Auto Trans Rebuild http://www.thesamba.com/vw/forum/viewtopic.php?t=516066&highlight=
AC in Squareback https://www.thesamba.com/vw/forum/viewtopic.php?t=...highlight= |
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Max Welton
Samba Member
Joined: May 19, 2003
Posts: 10972
Location: Black Forest, CO
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| Posted: Wed May 28, 2025 8:02 pm Post subject: Re: Wind sensitivity |
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I am familiar with caster shims (type-1). Had some in my 67 KG to good effect. I had a 63-based baja that was a white knuckle ride in the wind. Oy!
Just to catch up, I tightened up the thrust adjustment on the top beam. They weren't exactly loose but they did accept "some" snugging up. I haven't changed the rear toe yet. I did put a few PSI back in the front tires as the steering felt sort of heavy. Not totally trusting the psi readings of my air-up tool. 
Took a drive down to Florence and back this morning ... ~100 miles. Car tracked OK although there was very little wind.
I'll tickle the toe next time I'm under there.
Max
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1967 Type-3 Fastback
Under the Knife https://shoptalkforums.com/viewtopic.php?f=24&t=151582
Home Stretch https://www.thesamba.com/vw/forum/viewtopic.php?t=767836 |
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Max Welton
Samba Member
Joined: May 19, 2003
Posts: 10972
Location: Black Forest, CO
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| Posted: Sun Jun 01, 2025 3:22 pm Post subject: Re: Wind sensitivity |
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Between snugging up the thrust on the top beam and changing the slight rear toe-out to slight toe-in I think I've got it under control. And I have the tire pressures right where they were on my old square, 20 and 30.
Drove down to a "cars and coffee" gathering of the Tri Lakes Cruisers club and it's tracking better.
Then again, not a windy ride. But I'm going to call this a win. Tentatively.
Max
_________________
1967 Type-3 Fastback
Under the Knife https://shoptalkforums.com/viewtopic.php?f=24&t=151582
Home Stretch https://www.thesamba.com/vw/forum/viewtopic.php?t=767836 |
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old_man
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Joined: June 19, 2018
Posts: 1414
Location: Newfoundland
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| Posted: Sat Jun 07, 2025 6:24 am Post subject: Re: Wind sensitivity |
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I had this problem. 2 things solved it for me.
1) I had installed the wrong front wheel bearings on my 67. Mid year change over or something and the bearings I should have ordered are slightly smaller. Very hard to tell but it started causing the wheels to not track straight. All that is to say is that you may have an issue somewhere else like bearing or torsion bar being loose.
2) I fabbed and installed a chin. It really helped at higher speeds. Less wind under the car. |
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