MWM wrote:

Good Evening All,
On my stock '65 fastback there are a set four leaf springs and a set of Traction Master traction bars. As I understand it, the traction bars puts the rear axle in a bind. So would replacing the polyurethane bushing with a set of roller bearings improve this or make it worse?
thank you

There is some binding, but what is the problem?  Depending what you want to do driving-wise there could be no issue.  If you are going to do track time, maybe they could hurt your times vs some more sophisticated suspension.  I installed traction masters on my '66 in the late '80's.  They are still there urethane bushings and all.  They stop wheel hop on my car and handling has been great.  Remember, Shelby's had them too, and had great success.

And, roller bearings will not change anything.  They will just make your suspension harsher.

  The issue is differing center to center distances between the front spring mount to axle center vs the center to center distance of the traction bars.  That tends to turn the whole axle housing a small amount under hard acceleration/deceleration.  That turning is not an issue on a stocker.  And, yes, there are now better ways of controlling the axle for any type of performance you are looking to do.

Others on this site can give you a more complete discussion.  Give us more info on what you want to do and how hard you are going to run.  We can give you more a better answer that way.
 

MWM wrote:

Good Evening All,
On my stock '65 fastback there are a set four leaf springs and a set of Traction Master traction bars. As I understand it, the traction bars puts the rear axle in a bind. So would replacing the polyurethane bushing with a set of roller bearings improve this or make it worse?
thank you

 
A clarification: the Traction Masters do not put the rear axle in a bind. The purpose of the TM is to keep the pinion housing nose from rising on application of torque to minimize spring wrap. There will be some rotation, depending on the type of bushings in the TM. Replacing the polymer bushings with roller bearings will result in the minimum deflection. Metal bearings will also transmit all the shock loading to the chassis and brinnell the bearings. This usually feels like a big bang that most folks dislike. This is the reason why there no commercial roller bearing kits to replace the polymer bushings. The full race guys replace the polymer bushings with aluminum bushings; same result, less money.

On a stocker most folks use stock rubber bushings. The older you get, the less you like the harshness of harder-than-stock bushings.

Or, you could use the current Mustang Steve favorite method and replace the four leaf / TM combo with a new set of four and a half leaf rear springs. MS has a 500 HP 427 in his car and he swears by his four and a half leaf springs.

Since I'm not an engineer(butteye I know a couple!) I can only guess butt.......The floating rear axle deal-io LETS the axle pivot and allows the traction bars to lift the body up...thereby pushing the rear tires down into the pavement. The springs still spring/suspend butt are not fixed/affixed to the rear axle housing.
Since the axle housing can easily rotate prolly a good point for squeaks though.
I just like the way they tend to lift the car upon acceleration! FoMoCo must have liked it too back in the 60's AA/SS and A/FX days.
They wuz winnerz!!
6sal6

The old drag racer's trick was to solidly clamp all leaves forward of the axle housing at each leaf, and remove any clamps behind the axle housing.  This effectively made the front half of the spring into a traction bar.  That's basically what the TM bars do.

I don't think "bind" is the right terminology, rather depending on the arc of travel they could affect suspension cycling and therefore effective spring rate.  "Bind" is a condition where the suspension effectively stops working and gets stuck.  I don't know that what the TM bars do is a bad thing though.  Are there better setups?  Absolutely, all you need is an LCA/panhard/torque arm system.  Do you hear the cash register ringing?  I sure do.  I think for the cost involved the TMs are a pretty good improvement, and the cost/benefit is high. 

I would not advise going to either a roller bearing or solid bushing for street or handling use.  This could cause bind because in a turn there needs to be some side to side deflection to allow the suspension to cycle differently on each side.  Poly will still deflect some.  Not as much as rubber, but some.  I think bearings would fail in this application too.  For a drag only car then solid bushings or spherical rod ends are always preferred, but its like running a spool; good for the strip, not for the street. 

Last edited by TKOPerformance (8/16/2016 4:02 AM)

Hornman wrote:

Don't make me start drawing vectors! It's all fun and games until someone starts doing math!

I think what we have is is a difference in nomenclature. What is being called "binding" of the rear end, the designers of the Traction Masters called "locating" the rear end. The TM bar was intended to make a parallel link with the front half of the spring. The front of the spring and both ends of the TM are pivot points, with the connection of the spring to the housing fixed. The intent of this configuration was to minimize pinion climb and spring wrap. Probably most of us have seem the slow motion movies of spring wrap and the resulting wheel hop. It's the wheel hop that breaks axles. Back in the day the racer guys would tune their TM setups by applying clamps to the the individual leaves to increase spring rate and further reduce spring wrap. In the mid to late 60's there were not many knobs to turn on suspensions, so they used what they had.

I've said it before.......You are da man,Ron!
6s6