Tubular PHB worth it?
11-23-2010, 03:15 PM
#1
Tubular PHB worth it? I have all UMI tubular rear suspension on my SS and it's tight, driving.
On my Z28 I've done some cheap/free mods like boxed stock LCA's with Energy Suspension poly bushings, etc.
I recently placed an order with someone and it came out to $119.95, it said I can get $15 off if I order over $120 so I found some poly PHB bushings for the stock phb and the total came out to $120.xx so I basically got them for free.
Now I was looking at a spare PHB I have, it seems strong enough to do it's job as far as push and pull on the bar, even though it twists real easy. But if the twisting is a bad thing then why are the tubular bars offered with spherical rod ends to allow twist since the bar is to rigid to twist?
I hit a wet spot on the road with this car while going 130mph and did a 360, I never hit anything and the stock PHB didn't get bent or anything. Thats seems like the most stress the stock phb will ever see in my case, and it held up.
Long post over a $100 part I know, I searched and read a lot but nothing answered my question.
On my Z28 I've done some cheap/free mods like boxed stock LCA's with Energy Suspension poly bushings, etc.
I recently placed an order with someone and it came out to $119.95, it said I can get $15 off if I order over $120 so I found some poly PHB bushings for the stock phb and the total came out to $120.xx so I basically got them for free.
Now I was looking at a spare PHB I have, it seems strong enough to do it's job as far as push and pull on the bar, even though it twists real easy. But if the twisting is a bad thing then why are the tubular bars offered with spherical rod ends to allow twist since the bar is to rigid to twist?
I hit a wet spot on the road with this car while going 130mph and did a 360, I never hit anything and the stock PHB didn't get bent or anything. Thats seems like the most stress the stock phb will ever see in my case, and it held up.
Long post over a $100 part I know, I searched and read a lot but nothing answered my question.
Last edited by Jays_SSZ28; 11-23-2010 at 04:26 PM.
11-24-2010, 02:56 AM
#2
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Panhard doesn't really encounter twist. By design it is pushed and pulled on length-wise. In those directions it is strong. Twisting, it may not be strong but doesn't need to as the forces here are minimal.
11-24-2010, 07:07 AM
#3
I have all UMI tubular rear suspension on my SS and it's tight, driving.
On my Z28 I've done some cheap/free mods like boxed stock LCA's with Energy Suspension poly bushings, etc.
I recently placed an order with someone and it came out to $119.95, it said I can get $15 off if I order over $120 so I found some poly PHB bushings for the stock phb and the total came out to $120.xx so I basically got them for free.
Now I was looking at a spare PHB I have, it seems strong enough to do it's job as far as push and pull on the bar, even though it twists real easy. But if the twisting is a bad thing then why are the tubular bars offered with spherical rod ends to allow twist since the bar is to rigid to twist?
I hit a wet spot on the road with this car while going 130mph and did a 360, I never hit anything and the stock PHB didn't get bent or anything. Thats seems like the most stress the stock phb will ever see in my case, and it held up.
Long post over a $100 part I know, I searched and read a lot but nothing answered my question.
On my Z28 I've done some cheap/free mods like boxed stock LCA's with Energy Suspension poly bushings, etc.
I recently placed an order with someone and it came out to $119.95, it said I can get $15 off if I order over $120 so I found some poly PHB bushings for the stock phb and the total came out to $120.xx so I basically got them for free.
Now I was looking at a spare PHB I have, it seems strong enough to do it's job as far as push and pull on the bar, even though it twists real easy. But if the twisting is a bad thing then why are the tubular bars offered with spherical rod ends to allow twist since the bar is to rigid to twist?
I hit a wet spot on the road with this car while going 130mph and did a 360, I never hit anything and the stock PHB didn't get bent or anything. Thats seems like the most stress the stock phb will ever see in my case, and it held up.
Long post over a $100 part I know, I searched and read a lot but nothing answered my question.
Actually, there is a slight bit of twisting that the PHB sees as the suspension rises and falls during normal driving. This occurs because the rear axle follows an arc during suspension travel, this arc being defined in the forward/rearward direction by the LCAs, as the LCAs are ridgidly attached to the body at one end and the rear axle at the other. This arc is not in the same plane as the side to side arc that is defined by the PHB, since the PHB is also ridgidly attached to the body at one end, and the axle at the other. Hence there is a slight "tug of war" between the LCAs and the PHB. Having rod ends or roto-joints on either of these components allows this small amount of twist to naturally occur, and any bind is eliminated.
The factory compensated for this by using soft rubber bushings, which allowed the required movement, and also isolated most noise and vibration. However, as we all know, the rubber also allows for somewhat less than precise control of the rear axle.
11-24-2010, 02:41 PM
#5
Well, yes and no...the poly bushings in the stock bar will limit the ability of the bushings to "twist", but force either the bar or the frame mount to do so. Secondly, if you've made any changes to the ride height, and the rear axle isn't centered in the car, an adjustable PHB might be a worthwhile investment.