Has anyone played with their TOW to get better more stability in turns?

[Skidplate]

I thought my 37 Coupe had at least a little TOW IN but when I did a more accurate measurement, it's almost exactly Zero Tow. Does fine at speed and OK in turns. Just wondering if anyone else has experimented. We have a lot of twisties here.

Edited May 24, 2023 by Skidplate (see edit history)

[Bloo]

How stable is it in a straight line? Tire friction will load the suspension members and tend to increase the toe with speed. The goal is to never have toe out at speed. There is no advantage to having too much toe, it just causes more rolling resistance and tire wear. Are your tires radial? Typically you can get away with less toe with radials because they have less rolling resistance. Radials drive fine at the stock setting too, but less toe is better if you can get away with it. If the tires are Bias, I would expect you to need the stock setting. On the other hand if it is stable in a straight line on the highway, and it has less than stock toe in, I would be tempted to leave it alone.

 

[edinmass]

 

I would run 1/8 of an inch in. But would also do a castor and camber sweep beforehand. Also with very old cars shocks, springs, all the front end, and the steering box should be inspected first. Toe is actually the LAST part of an alignment. Air pressure in all four tires is the first. 

[Skidplate]

New shocks. Entire front end pulled apart, cleaned, inspected, all seals replaced. Put back together and aligned with positive castor (instead of original negative). New radials with all four set to 30lbs. Pretty stable going straight, just dives a little in the curves. Lots of body role compared to modern vehicles. I'm wondering if uping my sway bars would help. I'm fine with simple mods as long as they're strictly Bolt On. Everything is tight and smooth so this IS the final tweek. Just took it to a touch IN on Tow. My steering wheel was just a hair off center anyway so that should also be corrected. Or I just made it worse... we'll see.

Edited May 24, 2023 by Skidplate (see edit history)

[EmTee]

17 hours ago, Skidplate said:

Put back together and aligned with positive castor (instead of original negative).

Really?  Does it track straight without constant correction?

[edinmass]

10 minutes ago, EmTee said:

Really?  Does it track straight without constant correction?

 

I agree.......I would run 1/2 degree negative.......body roll on a pre war car is common. Try a car a few years earlier........much more noticeable. Basically the car is a 45 mph car, and with todays driving conditions people tend to speed most of the time. Personally I'm not a fan of radials, but I understand why many people use them. Springs, shocks, steering box were all designed for bias ply..........also rims are not engineered for radials and rim cracking and failure can occur....especially on rusty or damaged rims that were repaired. Good luck.......Ed

[Skidplate]

It tracks really well. Even at 70mph (which I'm finding is too much rpm) it still does fine. I took the tow in a little which almost got the steering wheel straight. It hasn't made any difference in corners though. Probably not enough adjustment to be noticeable. I'm thinking it might be best to leave it alone as all other handling characteristics are smooth and responsive. Best be thankful for what I have. Might even take it back out to Zero tow for minimal drag. 

[Morgan Wright]

Depends what year the car is. The E series (1918) has zero caster, I was shocked to see my axle is backwards. Somebody long ago took out my axle and replaced it backwards and it makes no difference because the caster is zero. I'm guessing somebody twisted the axle in a ditch or fender bender, and bought a new one and put it in backwards left wheel to right wheel. The axle is totally symmetrical, so it doesn't matter. I know it's backwards because the stop for the steering linkage is on the wrong side of the axle.

 

Theoretically a car with zero caster should be all over the road but it's not. 

 

Here is a pic of a Ford with zero caster.

Edited May 28, 2023 by Morgan Wright (see edit history)

[Grimy]

Aaarrgghh!  I can't take it any more!  It's TOE-in, at least in any book I've ever read.  As in "pigeon-toed."  You guys are buggering up searches in the future for people with questions about TOWing a vehicle.

[EmTee]

I was searching for something effective for toe fungus and I keep turning-up these discussions about front suspension alignment and tire wear! 

 

[raydurr]

I dont think you use wood boards to set toe in .

Edited May 28, 2023 by raydurr (see edit history)

[Grimy]

11 minutes ago, raydurr said:

I dont think you use wood boards to set toe in .

Only if I have bald tires in front....or no tires...  🙂

[AzBob]

 

Egads, yes,TOE IN.

[Bloo]

Toe in really doesn't have much of anything to do with stability in turns. As I mentioned earlier it's reason to exist is to counter tire drag that loads the suspension and attempts to make the suspension toe out at speed.

 

Toe out will make the car "turn in" fast, or respond quickly to steering wheel input, but will tend to make the car unstable in a straight line. Excessive toe in might make the steering less responsive though.

 

One thing to pay close attention to when setting toe is the length of the tie rods. They need to be identical. They are designed at a specific length to follow the suspension without changing the steering angle. If the two tie rods are not the same length, neither will be the correct designed length to follow the suspension. The car will steer itself in corners as it rolls over pebbles and ruts. This is known as "bump steer" and is bad news.

 

Prewar ideas about what a good car feels like are at odds with today's ideas. Part of the Buick experience was a smooth floaty ride. It is intentional. The roads were horrible. Body roll comes down mainly to the anti-roll bars, but also the spring rate and the shock absorbers. Those are the places to look, not toe.

 

Straight line stability is usually better with more negative caster, but on cars with manual steering you can make it really hard to steer at slow speeds if you overdo it. Some manual steering cars did use a degree or so of positive caster, at least in the postwar era. I'm with Ed, I'd run it a degree or so negative.

 

Pick up a copy of "How to make your car handle" by Fred Puhn. That will teach you the basics.

 

Edited May 28, 2023 by Bloo (see edit history)

[Morgan Wright]

Aargh!! I can't take it anymore. I tried to search for castor oil and all I found was how to set the wheels on old Buicks

[Skidplate]

Morgan you're really enjoying all of our miss pellings. Between you and Grimy and Emtee's tow fungis. Or is it fun Gus? I can never remembur. I love you guys though, fungus and all.

Oh, and bringing my toe in a little had no effect. Steering wheel is a little straighter but that's about it. Actually, god forbid, I'm thinking of fitting it with beefier sway bars in the front and matching ones in the rear. Or is that spelled REER?

And I like my highly calibrated Wooden Boards. At this point it's all about perspective anyway. 

Edited June 1, 2023 by Skidplate (see edit history)

[EmTee]

I didn't see any mention of the tires that you are running.  In any case, have you tried experimenting with tire pressures?  The book calls for what would be considered very low pressures by today's standards (i.e., low 20s psi).  I am running 7.00-15 reproduction bias-ply tires on my '38 and after driving with different pressures I settled on 34 psi front and 30 psi rear.  The tires run cool and the ride and handling is good.

[Skidplate]

That's a good question. I have played with tire pressure a little. Started at 20 something, went up to 30 then to 35. I'm running a bit more aggressive radials (less street, more dirt and snow) stiffer sidewalls. I've settled back to around 30 front and back. I might drop the rear a little but really haven't seen as much handling difference than just ride difference. More air, rougher ride. Less air, sloppy handling. Although I haven't tried "more air, disregard the uncomfortable stiffer ride, and see how it does then in curves". I'm still suspecting modern sway components may be the only practical fix. Or just slow way down in curves....nah. 😆

Edited June 1, 2023 by Skidplate (see edit history)

[EmTee]

34 minutes ago, Skidplate said:

More air, rougher ride.

Yes, that's when I started letting air out.  In my case I wanted as much pressure as I could tolerate ride-wise to keep temperatures down (I'm running tubes).  35 seemed to ride noticeably harsher, so 34 is where I settled.  Rear carries less weight, so 30 ~ 32  psi seems good for me.

[nat]

On 5/24/2023 at 1:27 PM, Skidplate said:

I thought my 37 Coupe had at least a little TOW IN but when I did a more accurate measurement, it's almost exactly Zero Tow.

     Those sticks won't give you an accurate measurement.  Put a stripe of masking tape across each tire and mark the tape.  With the weight of the car on the king pins, compare the distance between those marks at spindle center height when they are dead ahead or faced aft, (I use a screwed together wooden "caliper").

     Lack of TOE IN will cause a car to choose one side or another on a straight road but would be less noticeable in a curve.  Too much TOE IN  might handle fine but cause, (inside?), tire wear.  

     This is a big, top heavy car with a crude suspension.  Slow down and plan ahead as if you were driving an overloaded dump truck.

     I don't know who misspelled what but "TOW" captured my attention.

     

[32buick67]

My 32 Buick manual has a great amount of details for setting wheel alignment, and I followed them and they worked perfectly...hopefully your later Buick manuals have even more details to help with your adjustments.

This is some info from prewar automotive engineering school books for those folks like me who are interested in deeper tech talk for understanding toe and steering geometry...sounds like if you setup your car per the mfg specs, you will meet the mainstream toe setup requirements, which will ensure the best enjoyable driving experience as others have mentioned, provided the tire pressures are within spec.

 

 

 

[nat]

     I don't know how the 32' suspension works but my 39' business coupe has a "radius bar" that prevents the rear axle from moving side to side.  Without that the car and axle would go in opposite directions when making a turn.  I suspect that loose bushings on that bar would feel little different than a steering box with lots of play.

     Here in the rusty NorEast, Ford trucks are famous for rotten cab mounts.  A truck with an A OK suspension/steering can be all over the road because, (without the cab to frame connection), turning the steering wheel results in some mushy combination of steering the wheels and shifting the cab on the frame.

     This may have nothing to do with the make and model of this thread but it may be of some universal troubleshooting use .

[Skidplate]

Thanks to everyone for your input. I'm assuming stiffer sway bars will be the final answer.

 

But I would like to note that my STICKS have worked out quite well on a number of different vehicles. They may not be conventional but the principle is solid. And that it takes the wheels and tires out of the equation makes those STICKS an even better idea. So there, I've said it. Ptshths!!

[EmTee]

What about replacing the front sway bar rubber with poly?  The hard part will be to find the right application that allows minimal modification of the poly bushings to fit the '37.

[Skidplate]

I actually did that long ago. I have a mill so have replaced almost everything rubber with UHMW plastic. So if and when I do find a good sway bar source, I know I can readily replace the bushings to fit. I more recently started a post about the car being squirrelly over railroad tracks (all probably the same problem) and it was suggested that the sway bar bushings might be the issue. And although there are no SB bushings, there is the shock strut bushings that connect the shock (and sway bar) to the axle. I looked the rear end over really close and determined that they might be a little too sloppy. They were already machined from UHMW but just didn't seem to set in place as firm as they should. I reconfigured how they sat in their cradle and I think my squirrelly issue has been solved. No promises as I only have one RR crossing to test it on but it looks (and feels) better so far. So my next question... Does anyone know a good Aftermarket sway bar maker? I guess I should post that separately, huh?

[EmTee]

I notice my '38 gets 'twitchy' when driving across a couple of culverts locally that have a grooved concrete surface with the grooves oriented in the direction of travel.  I attribute that behavior to the reproduction bias ply tires.  It feels stable under all other conditions (including wet pavement).