Cause for oversteering

K

Keith

Senior Member
Over steer does alignment influence oversteer? My A is quick to oversteer. The toe in is about 1/16”
 
1/16" would not cause oversteer. I might suspect loose tie rod ends or drag link ends which would allow the front wheels to abruptly move more once they came off straight ahead when turning.
 
Most likely cause is a loose or worn ball at the end of the wishbone. Also could be other loose steering system components. I assume you have checked the tire pressure because low tire pressure in the rear can cause oversteer.
 
I have a 1930 Tudor and installed an anti-sway bar from a late model Crown Vic in the rear to reduce the oversteer. I blamed the higher center of gravity of the sedan body in the back half of the car. It was really only a problem when I started driving the Model A after driving my modern cars. You need to drive the Model A a little different; (or put in the anti-sway bar).
Of course, this assumes that your front and rear suspension are in good working order.
 
Slightly dropping the tire pressure on the front and/or slightly increasing the rear can help.
See if the rear axle is swinging side to side on the spring shackles, if it swings excessively adding a rear track rod would help. Do you have working shocks?
 
I am running Snyder tube shocks front and back and have rebuilt front end, tie rods etc.
I will try reducing the front tire pressure to 33/35 and 40 in the rear.
 
Keith, Are you using Flota Mota engine mounts? They are not able to hold the engine/gearbox assembly in place like the original solid ones do. That allows the flywheel housing to move sideways, taking the ball at the back of the A frame with it. That alters the alignment of the front axle. The same thing happens to the torque tube but to a lesser degree. The result can be over steer.
I have removed the soft mounts from a couple of my cars and their handling was transformed.
 
Oversteering is when the rearend breaks loose and starts to come around. Usually the cause is too much power, not enough traction and a heavy right foot.

Most people on this forum won’t have an oversteer issue.
 
Hitman said:
Oversteering is when the rearend breaks loose and starts to come around. Usually the cause is too much power, not enough traction and a heavy right foot.

Most people on this forum won’t have an oversteer issue.
Click to expand...

Agree about most people won't have the issue but over steer begins well before the rear end breaks loose (the most extreme form of it).
 
Hitman said:
Oversteering is when the rearend breaks loose and starts to come around. Usually the cause is too much power, not enough traction and a heavy right foot.

Most people on this forum won’t have an oversteer issue.
Click to expand...

Exactly what I was thinking. I’ve always thought it was mainly caused by bad weight distraction and aggressive driving in curves and corners. One would have a hard time experiencing oversteeer in a heavy under powered (40 horsepower) front engined Model A. It’s more likely you would experience understeer due to the Weight in front.

A light rear engine car with 40 horsepower is another thing. I experienced it when I bought a 1952 Porsche 356. I drove too fast into a curve and did a 360 degree spin. I was lucky that I never went off the road.

David Serrano
 
Lowering the front pressure slows down the steering response, raising the rear pressure reduces the sideways deflection on those tires. This is a way to find tune handling in some cases. Practice moderation, don't get too carried away doing this. :)
 
I've had a steering issue that appears to have been caused by the opposite problem: too much toe in. As I entered curves at normal road speeds, our S/W Fordor felt like it was diving into the curves enough that I felt like I had to counter-steer. I'm not sure what the proper term for that behavior would be - I called it "oversteering" - but that might not be correct. After doing some frontend work, the same behavior was there. A friend and I found that the toe in was a bit more than half an inch - way over spec. We adjusted it to about 3/32" and the behavior went away.

Hope this helps a bit in sorting out the OP's issue!
David
 
Hitman said:
Oversteering is when the rearend breaks loose and starts to come around. Usually the cause is too much power, not enough traction and a heavy right foot.
Most people on this forum won’t have an oversteer issue.
Click to expand...

My thots, too! most A drivers won't have the problem unless something is amiss! worn parts, for example! I never thot of oversteer as described above. but... his definition is a correct one as i read online tech. but factoring in too much power...oops! sounds a bit hot-roddy... :rolleyes: no doubt the real culprit is:

(as stated)

"and a heavy right foot." :p
 
Seems my post (post 8) about the soft engine mounts hasn't been understood.
Let's say the driver is turning left. The front of the engine/drive line is held fairy well in place in the chassis by the front engine mount. With the soft engine mounts, the weight of the engine and gearbox want it to keep going in the same direction but as the car goes left, it moves the right side of the car a little. That takes the back of the A frame with it because it is attached to the flywheel housing. That turns the axle to the left. Now you have the steering AND the axle steering left. The front and of the torque tube has also moved to the right. That turns the rear axle to the right, exaggerating the "axle steer"(for want of a better term).
In other words, the engine and gearbox unit is rigid and so is the torque tube and back axle. They articulate at the universal clam shell and add to the steering initiated by the driver. Result....Over steer.
Henry had it right and once again, our "improvements" detract from his design.
 
No mention of whether the OP is using bias ply tires or radials. If radial tires are used then this could increase the oversteer because the tires flex more.

For my heavy car I run more tire pressure in the rear and use a track rod in the rear. Most of the discussion has been focused on the front but the problem could be in the rear.
 
Just as NK said in Post #17, radial tires may increase the oversteer problem because they flex more side to side. When I switched to radials on my ‘29 Fordor (heavy on the rear axle) I encountered a significant, scary increase in oversteer. Increasing the rear tire pressure helped. After reading Synchro’s posts, I think float-a- motors may also be contributing to my oversteer issues.

W. Michael
 
Problems arise with Float-A-Motor mounts when only the rear engine mounts are used. The front Float-A-Motor mount, often not installed, is a very necessary structural mount.
 
On my original post:
I have completely rebuilt the front end with new spindles, kingpins, tie rods end, pitman arms standard length, tube shocks, and new bias tires. I have original type motor mounts and the wishbone ball in the bell housing is round not worn and using the original set-up (not the rubber ball) The condition existed prior to all of this so I'm a little perplexed. The steering is easy not hard just very quick on turns seems more when cornering into right hand curves. Maybe a bent axle?
 
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