0° Camber

[Barry Wolk]

I thought I read, on this site, a cure for front-end shimmy on early cars. If I remember correctly a 0° camber solves most of the problem. Was there more to it? Was I dreaming?

I seem to recall the need for a high camber being needed due to the typical high crown of old roads. Since the roads I plan on traveling with my '33 are pretty flat, that need no longer exists.

I did search for the thread, but couldn't find it.:confused:

[Rusty_OToole]

It may have been me. I was addressing the question of replacing old suspension with more modern suspension, or adding power steering.

My view is that if the old suspension is rebuilt and aligned to factory specs, the steering is surprisingly light and accurate at least good enough to negate the need for power steering.

If you want it to be even more light and responsive here is a trick that was used by German car makers for decades. When aligning the front end cut the caster to 0 or close to it. This makes steering easier and sharper. But it reduces the self centering action and can result in shimmy. To prevent shimmy, install a steering damper. This is what the Germans did even on the VW Beetle. Chevrolet did the same thing on the first Monte Carlos.

Another trick that helps easier steering is to pump up the tires to 32 PSI. Your tires will last longer and you will get better mileage as well.

I know people who have had the front end rebuilt and aligned on beam axle cars and early IRS cars from the king pin era. All reported that the steering was greatly improved, very easy to steer except at a dead stop and they no longer wanted to change the front suspension or add power steering.

[Rusty_OToole]

It is caster that makes the front wheels self aligning and prevents shimmy.

In the late 30s a lot of car makers experimented with easier steering and softer springs and had shimmy problems. They cured them by adding kick shackles, or on Packards they added oil filled dampers on the end of the bumpers. Jaguar used a weighted bumper rubber mounted to the frame, if you took out the rubber mounts the steering would shimmy.

IFS eliminated a lot of alignment and front end problems but introduced design headaches of their own.

On your 1933 car I would definitely rebuild the front end carefully including the springs. You want to eliminate friction between the leaves as far as possible. Add a steering damper and have the front end aligned carefully with minimum caster. Remember, as you load passengers and baggage on the car the back goes down more than the front and this can reduce caster. You need to take this into consideration when doing the alignment.

With a set of good shocks on all 4 wheels, a rebuilt front end, and rebuilt springs in the back you may be surprised how well your car rides and handles at least on good roads. The old solid axle cars don't ride so well on real rough roads because of limited suspension travel. But on decent roads they can have a very nice ride.

Edited January 28, 2011 by Rusty_OToole (see edit history)

[Barry Wolk]

I thought that toe-in provided the self centering. Please educate me.

I think I have my wife convinced to take a drive across Michigan next year, but I want it to be a pleasant drive. I have new tires and had American Arrow true the wire wheels. Chris, at Wetmore's, mounted and balanced the tires and said that AA did an excellent job. They were static balanced using a relatively small amount of weight. I can detect no wear in the king pins or tie-rod ends and I've restored all the original settings to the trailing arms. The shocks have new fluid and bushings and seem to be working well. Have I missed anything?

[Larry Schramm]

Barry,

Rusty is correct on caster giving a vehicle the self centering of the wheels. The more positive, the more it wants to go straight. Here is a link on what the effect of where the caster is set.

Larry

Wheel Alignment Explained - What is Caster, Camber, Toe In, Toe Out, Alignment - Four Wheel Alignment

[Rusty_OToole]

If you want leaf springs to work smooth and easy you have to take them apart. Use a disc grinder and fine grit disc to polish away all rust and smooth out the notch that gets worn at the end of each leaf. Paint the leaves then Reassemble with suitable nylon sliders at the end, or if there is no provision for sliders, use thin strips of nylon between the leaves. Teflon is even more slippery but too soft and squishes out. You should also rearch the leaves as necessary. Or leave all this to the local spring shop if you have one.

[Barry Wolk]

I used a 2" wide EPDM tape along the length of each leaf. All of the squeaks went away.

This car has a very interesting rear suspension. It has two half springs attached at one point on the frame. The other ends attach to brackets on the rear axle.

[Rusty_OToole]

Toe in is for one purpose only, to make up for play in the steering mechanism.

When the car is going down the road the forces acting on the tires, tend to push the front of the tires apart. This takes out any slack in the tie rod ends. When this happens you want the tires pointing dead straight ahead. So they have to toe in a little at rest, about 1/8" to compensate for the clearance in the tie rod ends.

In the thirties race car mechanics had a slick trick to get the toe in perfect. They would take 2 flat steel plates, about 1 foot square, with grease between them. They would drive the car slowly over the plates and see what happened. If the top plate twisted one way or the other they knew the toe in needed to be corrected. If the plate did not move they knew the alignment was perfect.

To do this test they would set out a board - then the plates - then a board all 3 the same height. Then drive the front wheel over.

This is the sort of thing you do on a race car where every detail has to be perfect. Such careful aligning of the toe in would reduce the drag of the tires on the road, reduce tire wear and make the steering as accurate as possible.

[Rusty_OToole]

I thought that toe-in provided the self centering. Please educate me.

I think I have my wife convinced to take a drive across Michigan next year, but I want it to be a pleasant drive. I have new tires and had American Arrow true the wire wheels. Chris, at Wetmore's, mounted and balanced the tires and said that AA did an excellent job. They were static balanced using a relatively small amount of weight. I can detect no wear in the king pins or tie-rod ends and I've restored all the original settings to the trailing arms. The shocks have new fluid and bushings and seem to be working well. Have I missed anything?

I don't think you have missed anything except a careful alignment. For a solid front axle you may need to have the alignment done at a truck shop, heavy trucks are the only vehicle that still has a beam axle. So if the local front end guy runs away and hides at the prospect of doing a solid axle, go to a truck shop. Your car will be child's play to them.

This should give you really good steering. You could add a steering damper but in your case I don't think it is necessary.

I don't know anything about EPDM tape. If it is slippery and doesn't squish out it should be fine.

Edited January 28, 2011 by Rusty_OToole (see edit history)

[Jim Rohn]

wow

lots of info being tossed around here

Mercedes had massive POSITIVE front caster angles (NOT zero), which the Chevrolet Monte Carlo did copy in 1973

Larry's link above is spot on, roll between the pages to read about toe, camber and caster

as long as your axle is not bent your camber and caster should be even from side to side, they are not adjustable without bending the axle

The toe is the only adjustable item on most solid axle front cars. SLIGHT toe in is ideal, not excessive. EXCESSIVE toe in will give you cupping and poor stability. Severe toe in will cause the tires to bounce ...

Toe OUT will wear the tires and cause it to be "squirrely" on straight stretches

On the other hand if you plan on autocrossing or road racing ... toe OUT and NEGATIVE camber is preferred, but not for normal street use ...

more info:

basic:

Wheel Alignment A Short Course

performance, maybe better (more advanced) info:

Caster, Camber, Toe

[Guest]

Jim, I will add to that; even VW Beetles from 1938-1970 had a caster angle between + 2 degrees 30minutes and + 2 degrees 15 minutes with the very early cars not having a steering shock at all. Camber set at Zero. I think the Mercedes cars had the most I've ever seen starting in the late 60's - 70's+

Those W cars when in a max turn would lean over like a extended forked Harley Chopper! a real outside/inside tire wearer if the tire pressures were below 32psi and you were not running Michelin's! They did go very straight!

Don

Edited January 28, 2011 by helfen (see edit history)

[Guest Max. M.]

Barry,

Rusty is correct on caster giving a vehicle the self centering of the wheels. The more positive, the more it wants to go straight. Here is a link on what the effect of where the caster is set.

Larry

Wheel Alignment Explained - What is Caster, Camber, Toe In, Toe Out, Alignment - Four Wheel Alignment

I fully grasped this principle by accident, when I was in high school I designed and built two go-carts, one ended up as a senior project. The steering on the first one was fairly simple with the spindles at 90 degrees. It worked fine, but I did not like the excessive rolling of the tires on turns, plus every bump pulled on the steering wheel. On the second project I tried to solve the rolling tire problem by leaning the spindles back a bit, that part made sense to me, as the wheels were to be turned they would also lean in to the direction of the turn. As I was assembling the cart and had the tie rods off with the wheels on, only then it hit me that positive caster also will return the wheels back, since both wheels turned all the way inwards as soon as they were subject to gravity.

[Rusty_OToole]

On a beam axle car the caster is adjusted with tapered shims between the axle pad and springs.

I would stick to factory specs myself.

Except, as I said if you want easier steering you can cut down the caster if you have a steering damper. But this is usually not necessary.

Edited January 28, 2011 by Rusty_OToole (see edit history)

[Guest De Soto Frank]

"I think I have my wife convinced to take a drive across Michigan next year, but I want it to be a pleasant drive."

Wonderful ! Suggest you take the Continental out on several lengthy test trips ahead of time, to make sure you've got any bugs worked-out before setting-out on a long trip with the spouse & luggage.

My wife is not an old-car person, but she has agreed to take several local trips ( hour or two each direction) in my various old cars; if any of them had left us dead on the side of road, I'm sure she'd refuse to take a long trip in them again.

As for your suspension, why not set it up to factory specs and see how it drives ?

If it's squirrely, then you can look for worn parts or make adjustments to the alignment settings.

It is not going to be as "sticky" to the road as a more modern vehicle ( longer / lower/ wider / heavier, wider tires, etc.), but it should ride and handle acceptably.

One characteristic of leaf-sprung vehicles is they tend to have a rocking-horse feel ( back and forth ) going over bumps and such; usually not a problem if the springs are free and the shocks are working... just a different feel than we get from post WW-II IFS.

A buddy has a 1989 Jeep Grand Wagoneer, which still has leaf-springs at all four corners, and has that "rocking back & forth quality" ...

My only other suggestion would be to do some math on the driveline / gear -ratio or put a tach on the car and drive it, and determine what its comfortable cruising RPMs are...

You'll probably want to keep the RPMs below 2,800 - 3,000 for prolonged travel, so whatever road-speed that translates to will determine what sort of roads you can comfortably run on.

[Graham Man]

Positive 2-3 degrees on almost any solid front axel (including new trucks). The salt flat cars run over 10 degrees positive. The more positive the more stable at speed. The only down side to caster is you are picking up the front of the car when you turn (harder steering). My 1928 Graham Paige would almost shake the wheels off the car at 35 mph when you hit a bump (0 degrees caster). I found original 1928 Graham Paige caster shims (3 degrees positive) now you can take yours hands off the steering wheel at 50 mph and hit all the bumps you want, the car is perfectly stable.

[Barry Wolk]

I'm assuming, from the majority of responses, that everything should be set to factory specs. In 1934 the Continental came with a steering damper. Doesn't that just mask a problem?

[Rusty_OToole]

I'm assuming, from the majority of responses, that everything should be set to factory specs. In 1934 the Continental came with a steering damper. Doesn't that just mask a problem?

Yes, in the sense that power steering masks the problem of hard steering or rubber tires masks the problem of rough roads.

I'm surprised they had a steering damper that early. But, as I mentioned earlier, all car makers were trying to improve their ride and handling, and running into problems with vibration and shimmy. They used various means to eliminate the problem, it seems Continental chose the direct approach.

[Guest De Soto Frank]

Barry,

It might just drive okay set-up to factory specs.

If it were my car, that is where I would start-out.