Sorry that is incorrect, if you look close there is only one dead perch and the spring works great with out the side movement! Gary
roadster 1297 no it doesnt actually work as it should, the reason that you dont notice it is due to the side steer which doesnt pickup the lateral chassis movement when the spring flexes. As it is positioned now the portion of the spring between the center cross member and the dead perch is a soild piece off steel with a bunch of spacers. The main leaf essentially acts as a panard rod to locate the axle but the spring action is similar to a 1/4 elipitical spring as the majority of spring effect is between the spring clamp and the non restrained shackle eye side. So instead of having say 30" spring you are actually riding on a 15" spring. When you drive your chassis skews right every time you hit a bump. If you get rid of that perch you will notice a much improved ride. If you dont believe me take you car for a ride and slowly hit a bump or small pot hole with just the left tire and then do the same but hit the same with the right tire, you will notice a tremendous difference in the bump felt comparing the stiff side to the free side.
I ran a steering stabalizer on mine. Just a gas shock from NAPA mounted on the left side of the frame on a tab welded to the bottom of the frame and the other end mounted to a clamp around the drag link. Took the bump steer out. Same concept at 4 X 4 trucks that are lifted. I think I had about $25 in my set up and could barely see it.
Im more sorry, that side acts like a rigid mount----because----its rigidly mounted. When that setup travels, there has to be some binding I would think, but Im a dumb Kracker.
Dick and Kracker,thanks for the posts on my setup. I have had some stock setups and enjoy them all, but I wish both of you guys were local so I could take you for a spirited ride and see how much fun my roadster is in the twisties and you would find out that it is a very controled but not stiff ride. Have a great day Gary
Hey man, I have a quarter elliptic front set up in a hot rod that noone believed would work. What saves you and me is the stiffness of the springs. I promise you that Im not saying that yours will not work, but It really isnt ideal----------------and neither is mine I sometimes just post here just in case someone is reading info that may be confusing or misleading. Just me though. BTW, Id love to ride in it
Actual Experience Here: Dad has a '32 tudor with Vega cross steering and 4-bar that wandered a bit on bumps. Obvious bump steer. He installed a dead perch on one side (acts like a panhard bar) and his problem went away. His other '32 tudor has F-1 side steer and stock Ford wishbone. No bump steer. No panhard required.
You will find that stock Ford suspensions from 28-41 have virtually no side sway as they were designed to have the spring mounted in tension such that the shackles move only up and down rather than swaying R to L and back. Ford changed their spring mountng method in 42-48 and installed Panhard rods front and rear to stop the shackle sway inherent in an untensioned cross spring mounting.
There is no cut and dried rule that a panhard bar will help. There are certain types of suspension that they work well on but even that is not true in all cases. Hairpins and 4 bars frame mounted will cause bind up in the suspension. They work well on circle track race cars because they only turn one way. Original Ford type with a wishbone were designed for a reason. It doesn't bind up. A car with wishbone suspension will always ride softer. The roadster in the pic was unbeatable in sports car racing in the 50's. It had basically stock 32 suspension. The car I have now (30 2 door) has a panhard both front and rear but only because it lifts the left front wheel on hard acceleration. I use it for vintage rally racing.
Panhard bar should be mounted on the frame the same side as the steering box. the other end usually locates on either the wishbone, batwing or similair. Bump steer is different to death wobble, death wobble is often caused by the tie rod being to thin a piece of tube, I don't use the 7/8" OD tube as seems to be standard in the industry but i use 1" OD, I've known quite a few people that have been pulling their hair out with death wobble and they have been cured by changing the tierod to a bigger diameter, the longer they are the more they have the ability to flex in the middle. More Castor will make the car go straighter but the steering will be heavier. Excessive castor as you see on altereds can cause severe death wobble when the power is stopped, like at the end of a burn out for instance.
Unfortunately a steering stabilizer is just a band aid for a poor system, a properly designed system doesn't need one.
D-russ your assumption is correct if you have zero or negative caster (axle top tipped forward) you are in for an adventure in driving but caster has less to due with bumpsteer issues that is something else. Settings today can be modified somewhat from specs of the 30's due to tire construction and increased tire widths. You should avoid excessive positive caster ( axle top tipped rearward) and with wider tires be in the area of 4-5* not exceed 6* caster. Excessive caster creates a shopping cart shake so in the case of caster adjustment less is better.
i would one if you have cross steer but i think cross steer and panhard bars look silly IMO. ill never run one
A panhard bar "locates" the axle on the frame. Shackles allow the axle to move side-side when you hit a bump. A panhard bar prevents this differential side-side movement of the axle relative to the frame. This is a relatively big deal when you are running a cross steering setup, because any sideways movement of the axle relative to the frame will result in what is called "bump steer" (the car adversely steers itself when the axle moves and the frame doesn't). Why? because the steering link is rigidly connected to the right wheel steering arm and the frame via the steering box. When the axle moves sideways, so do the wheels, but the steering link doesnt move, so the wheels turn and "bump steer" the car. It doesn't affect vehicles with side steering as dramatically. Lots of words, but i hope this helps.
Adjusting the castor isn't gonna correct bump steer, bump steer comes from incorrect geometry, If the geometry is right you won't get bump steer. 5-7 degrees castor is usually fine although if you can use less do so.
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