Rear end gets squirly on sharp curves

[carolinamudwalker]

First I have 19" Radial tires and love them. I can take my hands off the wheel for a very long time and the car tracks straight as an arrow. But in the mountains on very sharp curves (as in you can almost see your own tail lights) The rear of the car does not want to track with the front. I know I have some frame twist, add the rear spring shackles shifting outward and the radial tires then god forbid a wet road and it really gets hairy. The front spring is new, I took the rear spring apart & ground The worn ends and lubricated the leaves. I have tube shocks from Snyder's . I could slow down but that is no fun. So the question is do you think a Pannard bar on the rear would help? Car is a sport coup Thanks

[DaWizard]

Ya know, if the rear of my car was squishy like you describe, I would up the tire pressure 5# to help keep the tire upright. The radial ply tires rolls at the sidewall, which is great for the modern low slung cars, but with the top heavy Model As it is way too much flex with the rest of the give the suspension has. Give the tires a bit more air and a bit stiffer sidewall.

My 2¢

[carolinamudwalker]

Wiz, they are 5:50 19 tires and I have increased tire pressure from 35 to 40 psi I do monitor pressure in the hot months. I have a sport coup so not as top heavy as some models. I think a lot of the problem is the spring shackle's on the rear shift the body away from the frame on tight turns. I think I will try the panhard bar also. Bob

[tbirdtbird]

"as in you can almost see your own tail lights"

Bob, you know a lot of us are gonna borrow that phrase!!! LOL

I think the Wiz might be onto something, worth a try.

With the car parked, try to rock the rear of the car and see if the shocks are still actually doing anything. With the driving you do you may have worn them out already!
You may need a stiffer shock, too.
I have no knowledge of Pannard bars (?Panhard?) but Geo Miller may

I had found a table of Monroe shocks online a few years ago, it was a Mopar-based pdf but it listed all the shocks they made. Could never find such a table from the US. I will see if I can find that link....
yay here it is

http://www.oldmopar.com/oldmopar/MountingLengthMonroe.pdf

[BILL WILLIAMSON]

I saw my own tail lights when I fell down, tryin' to get Vermins' spare on its' RACK! Glad it wuzn't RAINING!

[carolinamudwalker]

Thanks Dave, I will check the shocks out when the car gets back on the ground. Still dealing with rear axles. Engine on its way to AER, All brake shoes being relined With non-woven bonded linings. (see Tech Questions Nov-Dec 2012) I will do a report on them after some hard miles. Bob

[plyfor]

Post #2 is correct , imo, and bias ply tires may be better for the skinny wire wheels and high road ht. Tires pick up about 3 to 5psi when hot so be careful there. I put the Lucas Vietnam tires on a slant window sedan with tube shocks and a Panhard bar on the rear. The car is very stable, a little stiff when unloaded but the front shocks I've posted about elsewhere are VW Empi's painted black. This appears to let the springs behave without abrupt bounce caused by gas charged shocks.

[History]

Sounds like you're loose! Throw a turn or two of wedge in and adjust the air pressures, you won't be able to say enough about the boys on the forum, everyone pulled their weight.


I agree on air pressure and you also may have something worn or lose. If you have a buddy who could video you in a turn you might could see what's happening or maybe a GoPro camera mounted underneath?

[carolinamudwalker]

Thanks plyfor I will try the panhard bar on the rear. I am sure the radials have contributed to the problem even though they have more braking surface at 5:50 19's Bob

[CarlG]

When I first put my Coker Radials on, I aired them up to 35psi, the same as I had in the Firestones. Then I read the fine print on the side of the tire: Max pressure 44psi. So I brought the pressure up a tad. Tires don't look like they are under inflated so much anymore.

[Big hammer]

On our new to us modern, we had one tire 6# low and three 3# low. What a hand full to drive in the wind, air up to 35# COLD pressure and now rides nice!
I have wondered how a panhards helps as panhards center the axle in the frame. My shade tree thinking is with spring shackles on each end, this allows too much moment. Must leaf springs that I no of only have one shack fix on the other end.
What we need is a anti roll bar for our A's, Any manufacturer listening?

[plyfor]

The vendor supplied pan. bar on the rear ( by the prior owner) was counteracted by one on the front pass side that had to be removed when tube shocks installed on the axle. I'm not sure with the transverse springs how much help the bars are except the rear sedan body appears to not sway as much. The tube shocks seem to provide some stiffness and dampening when the upper mounts are connected to the rear cross member at an angle.

[carolinamudwalker]

Thank, That is what I am going to try.. No panhard bar on the front.

[plyfor]

Forgot to mention that when I used to sell tires to help with college expenses, radials were just coming to the Amer. market and customers would come in saying the tires looked flat. The radial sidewalls do flex more. There was also a difference between the steel belts and the bias plies at the time. Also, the manuf. told us the max. pressure is more a liability statement and to defer to the car manufacturer's recommended pressures.

[Mitch]

Forgot to mention that when I used to sell tires to help with college expenses, radials were just coming to the Amer. market and customers would come in saying the tires looked flat. The radial sidewalls do flex more. There was also a difference between the steel belts and the bias plies at the time. Also, the manuf. told us the max. pressure is more a liability statement and to defer to the car manufacturer's recommended pressures.

Yep agree little off topic,

Every modern car has a spec label for recommended tire pressure in the door jamb next to the VIN sticker. With that being said there are a few instances where you need to deviate and that is from real world experience.

A couple examples are
The earlier Ford Exploders called for i think 24psi NO WAY

and the 2500 - 3500hd pickup's calls for 80 in the rear.. if you run that unloaded you'll kill the center tread plus ride hard as a rock.. i run 55 in them unless i'm trailering.

[plyfor]

Also agree some deviation is case specific. A neighbor pulls a 10k# rated horse trailer with a 3/4 ton pickup and it says 80 on the 6 ply sidewalls. She ran 50 in them, way too soft possibly by neglect, and we put 74 cold and her mileage went up as well.

[Mitch]

she should prob have 10 ply on that truck

[plyfor]

Oops, you're correct. I think they are 10 ply. I was thinking of my 1/2 ton which is 6 ply.

[tbirdtbird]

the sidewall number is the max allowed by the tire maker.
The sticker on the door jamb is the car maker recommendation for that tire on that car.
and yes some deviation from the car makers advice is sometimes needed, based on experience.
My RAV calls for 32 and rides like a tank at that number which I always thought was way too high. Not that many people haul concrete blocks in a RAV. So I backed down to 30 and now it rides like it should. Handling was not affected.

[carolinamudwalker]

I looked on my door jam and all I saw was nails. Sorry I don't know how to but the funny thingies at the end of my post