Ron Pope Motorsports                California Custom Roadsters               

Radius rod bolts

I've been thinking over my options. It seems like it I put Heims on the batwing end of the radius rods that there will be constant changing of the Caster. Even if it is a small amount ( just the movement of the Heims) that it will be a handful to drive. Any comments?
 
I've been thinking over my options. It seems like it I put Heims on the batwing end of the radius rods that there will be constant changing of the Caster. Even if it is a small amount ( just the movement of the Heims) that it will be a handful to drive. Any comments?
you mentioned before that you were running a four bar? The point of the four bar setup is so your caster will NOT change. Are you sure you are running a four bar setup or are you running radius rods? Four bar has two mounting point in the rear, and two mounting points in the front. radius rods have two mounting points in the front and ONE in the rear. I know you may know this, but just trying to figure out what you are using.
 
I changed my front to 4 bar and I am going to leave the clevis ends on. But I drilled out the batwings for a brass bushing. Just snugging the nut and drilling the bolt for a cotter pin.
Doesn't seem to bind. By the way this is a new build and this is what I'm comfortable with doing.;)
 
I do have a 4 bar. I built the car from frame up . Just think I made an engineering mistake on this. Man; I hate to weld on 2 more batwings to my pretty axle.
 
I do have a 4 bar. I built the car from frame up . Just think I made an engineering mistake on this. Man; I hate to weld on 2 more batwings to my pretty axle.
ok i gotcha. I've never seen it done, but I don't see any reason NOT to run heims on the front and rear, but I would NOT do it without a panhard bar. One thing about all the manufacturers also say, is always run a panhard with 4 bar setups. With bushing ends on a four bar, it doesn't do much to help anchor the side to side movement of your axle, but The heims would do absolutely nothing to help hold the front from lateral movement. I know it sucks big time to redo stuff, but just from one gearheads opinion?...... Weld on the extra batwing, use 4 bushing ends front and rear, and run a panhard bar. That is the proper way to do it, no matter what other people use that may even work. Google pics of four bar setups, and i couldn't find ONE that wasn't done this way, with many many pictures I went through. some didn't have a panhard, but ALL used bushing ends mounted on both sides. My brain says there MUST be a reason for this. As far as changes in caster goes, as long as your bars are the same length, and run parallel to each other (top and bottom bars should be mounted equal distance from each other front to back) there should be no caster change. Enjoy your build! :thumbsup:
 
I've been thinking over my options. It seems like it I put Heims on the batwing end of the radius rods that there will be constant changing of the Caster. Even if it is a small amount ( just the movement of the Heims) that it will be a handful to drive. Any comments?
Butch27,

I have to disagree on your fear of using Heim bearings in your suspension. Good quality spherical rod ends should have no slack and will not cause any steering issues. They are used in most all drag racing and formula and Indy type cars with no problems. Just look at the helicopter control linkages in the rotor head and tail rotor systems. There can be zero play in these systems. The biggest complaint with spherical rod ends is noise and vibration or road noise being transmitted to the driver. This is mainly a driver/builders choice. I personally dislike the poly style of bushings that have become so popular. I've been building professional race cars for 40 years. That ranges from T/F dragsters to true race bred road racing cars. Before that I hung my carcass under rotor blades for-2 1/2 years in Vietnam so I do have a good feel for the spherical bearings. I would prefer a true bonded rubber bushing for several reasons. But as they use to say, "You Pays Your Money And You Takes Your Choice." Hope this will help you in your decision.

George
 
ok i gotcha. I've never seen it done, but I don't see any reason NOT to run heims on the front and rear, but I would NOT do it without a panhard bar. One thing about all the manufacturers also say, is always run a panhard with 4 bar setups. With bushing ends on a four bar, it doesn't do much to help anchor the side to side movement of your axle, but The heims would do absolutely nothing to help hold the front from lateral movement. I know it sucks big time to redo stuff, but just from one gearheads opinion?...... Weld on the extra batwing, use 4 bushing ends front and rear, and run a panhard bar. That is the proper way to do it, no matter what other people use that may even work. Google pics of four bar setups, and i couldn't find ONE that wasn't done this way, with many many pictures I went through. some didn't have a panhard, but ALL used bushing ends mounted on both sides. My brain says there MUST be a reason for this. As far as changes in caster goes, as long as your bars are the same length, and run parallel to each other (top and bottom bars should be mounted equal distance from each other front to back) there should be no caster change. Enjoy your build! :thumbsup:

Dale,

Why do you think heims won't center your front axle? They will work as good if not better then a poly or rubber type bushing. A poly will not twist or roll out of axis as they are usually to stiff. Rubber can deflect but can also compress and cause minute length changes. A heim can see any twist or roll in any axis with zero length change. Just something to think about before you rebuild your front suspension brackets.

George
 
Dale,

Why do you think heims won't center your front axle? They will work as good if not better then a poly or rubber type bushing. A poly will not twist or roll out of axis as they are usually to stiff. Rubber can deflect but can also compress and cause minute length changes. A heim can see any twist or roll in any axis with zero length change. Just something to think about before you rebuild your front suspension brackets.

George
Nothing at all wrong with a heim to hold the four bar from moving front to back. It will work far better than a bushing end for front to rear movement because it doesn't give. But....if you bolt all four bars up with heims to the frame in the rear and the axle in the front and nothing else is bolted up to the axle, you can slide the axle left and right with ease because they are designed to pivot. NO front to rear movement in the axle, but it will have Lateral movement. Most heims are designed to pivot about 28degrees, and some up to 60. They are perfect for locking your front end on a four bar setup front to rear, but you will have to hold lateral movement some other way. Yes the buggy spring does that to a point, just needs a little help. Like I said, speedway and just about all the others recommend panhard with any 4 bar setup.
 
I think it's a good idea to use a panhard regardless of hair pins or 4-bar. With the transverse leaf, yes the leaf itself is fixed with no side to side movement, but there is lots of movement in the shackles.
 
Nothing at all wrong with a heim to hold the four bar from moving front to back. It will work far better than a bushing end for front to rear movement because it doesn't give. But....if you bolt all four bars up with heims to the frame in the rear and the axle in the front and nothing else is bolted up to the axle, you can slide the axle left and right with ease because they are designed to pivot. NO front to rear movement in the axle, but it will have Lateral movement. Most heims are designed to pivot about 28degrees, and some up to 60. They are perfect for locking your front end on a four bar setup front to rear, but you will have to hold lateral movement some other way. Yes the buggy spring does that to a point, just needs a little help. Like I said, speedway and just about all the others recommend panhard with any 4 bar setup.

Dale,

I guess I shouldn't respond to anything late at night. After re-reading your post I realized I misunderstood what you said. I thought you were talking about a panard bar using heims would change lengths. As for using a panard bar with a 4 bar or a pair of radius rods, I think you need it for either setup. Carry On!

George
 
I think it's a good idea to use a panhard regardless of hair pins or 4-bar. With the transverse leaf, yes the leaf itself is fixed with no side to side movement, but there is lots of movement in the shackles.

I don't see how either of the designs being discussed - four bar or radius/clevis - can control lateral movement very well. Neither is stiff enough to counteract the forces being applied. I compromised by adding a steering stabilizer, and it was a big improvement.

Jack
 
Lateral movement w/a transverse spring is controlled BY THE SPRING !! In order for it [the spring] to work properly it must be installed "in tension" . In order for that to happen , the distance between the spring pivots must be greater than the spring in it's relaxed state . You should HAVE to use a spring spreader to install the spring !! The tension in the spring will then self center the the axle to the frame. It's all really pretty simple.
dave
 
Dale,

I guess I shouldn't respond to anything late at night. After re-reading your post I realized I misunderstood what you said. I thought you were talking about a panard bar using heims would change lengths. As for using a panard bar with a 4 bar or a pair of radius rods, I think you need it for either setup. Carry On!

George
Hey I wrote it late at night so I doubt i made sense! :sleep: And yes I'm using some sort of locator front and rear on mine. I just think it sure can't hurt! Get into some twisting roads and I just don't want to trust a flexible spring to hold things in place and I'm using buggy spring in the rear too. My two Abe Lincoln's....
 
Lateral movement w/a transverse spring is controlled BY THE SPRING !! In order for it [the spring] to work properly it must be installed "in tension" . In order for that to happen , the distance between the spring pivots must be greater than the spring in it's relaxed state . You should HAVE to use a spring spreader to install the spring !! The tension in the spring will then self center the the axle to the frame. It's all really pretty simple.
dave
That's exactly right but you can get lateral movement because the shackles can pivot. I'm not saying you MUST run a panhard a lot of people don't and it works. Just my opinion some sort of locator is optimal. I just made a home made spring spreader myself. Ugly as hell but it works! :thumbsup:
 
The tension in the spring will then self center the the axle to the frame.

Dave, how can it do that except under static conditions? When one wheel moves up (or down) on a bumpy road, spring tension is no longer equal on both sides. I'm pretty sure the unequal tension - plus the unequal length that results with one side of the spring having a different bend radius - will push/pull the axle to one side or the other. If that's not correct, I need an explanation.

Jack
 
There may well be some momentary off-centering of the axle , the key-word being momentary.... in -you'll never feel it momentary. I simply can't understand why some feel the need to re-invent the wheel , i.e. a suspension system that has worked well , albeit not perfectly , for over a century ???? I would opine that there is more lateral movement in the sidewalls of the tires than in the transverse spring front end.
dave
 
No panhard on mine and it has been driven many miles (by PO fitzee and a few by me as well!) on good/bad/indifferent roads. No issues at all with darting or the like.
Reversed Corvair box and a long drag link. Tight spring and shackles.
Not sure if I posted this before...but check out the two ruts in this part of the highway. We have many stretches like that due to a lot of big rig traffic I guess.
65-70mph and a full day to cross the island.
Left "St John's" at 7am, dealing with every possible road style and also road construction along the way, and rolled on the "Port aux Basque" ferry to Nova Scotia at around 11pm that night. (Inc visiting friends and fuel/Tim Horton stops along the way of course!:coffee::D)
No issues at all.
Vid's less than 30 sec long...use 360p for a good quality....
 
I'm not saying you MUST run a panhard ... Just my opinion some sort of locator is optimal.

What about the fact that the panhard itself pulls/pushes the axle left and right as it moves up and down? Maybe that's not an issue due to the limited travel of these suspensions? Shackle movement is probably greater than the radial difference that occurs due to panhard movement. Overall, I guess there's a net gain with the panhard.

Jack
 
What about the fact that the panhard itself pulls/pushes the axle left and right as it moves up and down? Maybe that's not an issue due to the limited travel of these suspensions? Shackle movement is probably greater than the radial difference that occurs due to panhard movement. Overall, I guess there's a net gain with the panhard.

Jack
If the panhard is level to start, then the side to side movement with such a small amount of suspension travel will be miniscule. Probably less than 1/16".
 

     Ron Pope Motorsports                Advertise with Us!     
Back
Top