[DeTomaso] Poly vs. Rubber suspension bushings

Julian Kift julian_kift at hotmail.com
Thu Apr 9 11:15:15 EDT 2020


Charlie,

Rather than one being better than the other, I'd prefer to say each has pros and cons. Personally I think it is more a choice of ride compliance dependent on your driving style, desired ride quality and feedback from the suspension. Rubber being most compliant then poly and after that it's a full heim (rose)  joint suspension. Even today most OEMs use rubber bushings on the assembly line!

  1.  Rubber is softer than polyurethane, so dampens more road noise and vibrations making for a smoother ride.
  2.  Poly being harder performs better in more aggressive driving situations, improving handling.
  3.  Rubber bushings are chemically bonded to their housings so the rubber stretches in dampening suspension movement. Conversely poly bushings are free to move in both the outer a-arm and inner tube (in most cases).
  4.  Rubber is maintenance free, poly requiring grease every 3-5 years typically. A grease zerk in the a-arm will get lubrication to the outer contact with the a-arm, but not the inner tube
  5.  It is perceived as easier to replace the rubber bushings with poly. This is true to an extent, as a home mechanic you can carefully cut the old bushing housings to collapse and remove them and then installation of poly is a breeze. That said to do it properly and with access to a hydraulic press (e.g. Horrible Fright $150 unit) it isn't that hard to press out the old bushings and press in new.
  6.  Cost has been a factor for the Pantera in the past, but Maserati Source has made in Italy oem style rubber bushings for $295 a set of 16, about the same cost as set of poly bushings from our vendors.

Be aware not all poly bushings are made equal, you might check what durometer hardness each vendor is offering as this will affect ride quality and harshness. I know Dennis Quella's offerings at one time had a round to hex center tube and inner bushing design, that attempted to confine one degree of freedom of movement, whether this actually provides better performance or not I cannot say.

Finally , you realize you are going down a rabbit hole..... as at some point you need consider your objective along with the suspension system working in unison as a whole. The single biggest upgrade I made to the performance of my GT5 was installation of 1 inch sway bays front and rear. Then there's varying opinion on the sway bar ball ends, adjustable shocks, spring rates etc.

Regards,
Julian
________________________________
From: DeTomaso <detomaso-bounces at server.detomasolist.com> on behalf of charlesmccall at gmail.com <charlesmccall at gmail.com>
Sent: Thursday, April 9, 2020 12:30 AM
To: detomaso at server.detomasolist.com <detomaso at server.detomasolist.com>
Subject: [DeTomaso] Poly vs. Rubber suspension bushings

Hi all

I decided to take advantage of being away from my car to fix a long-time engine oil leak by removing my suspension, radiator, etc 😊



You know how these things go… I asked the guy to check the car over while he had the engine out, and the task list is growing, so my car is in a bunch of pieces right now.



Mike Drew is helping source parts for me, and he asked if I wanted poly or rubber bushings. I know that this subject has been discussed a million times, but I didn’t take notes. My specific question:



1.      Is it commonly accepted that poly is better but will squeak without proper lubrication? Rubber is maintenance-free but degrades over time and doesn’t work quite as well?
2.      How difficult is it to lubricate them? Is this a matter of installing a zerk fitting and zapping it once a year? Do you wipe it on? How easy is it to access them without a lift?

Thank you!

-------------- next part --------------
   Charlie,

   Rather than one being better than the other, I'd prefer to say each has
   pros and cons. Personally I think it is more a choice of ride
   compliance dependent on your driving style, desired ride quality and
   feedback from the suspension. Rubber being most compliant then poly and
   after that it's a full heim (rose)  joint suspension. Even today
   most OEMs use rubber bushings on the assembly line!

    1. Rubber is softer than polyurethane, so dampens more road noise and
       vibrations making for a smoother ride.
    2. Poly being harder performs better in more aggressive driving
       situations, improving handling.
    3. Rubber bushings are chemically bonded to their housings so the
       rubber stretches in dampening suspension movement. Conversely poly
       bushings are free to move in both the outer a-arm and inner tube
       (in most cases).
    4. Rubber is maintenance free, poly requiring grease every 3-5 years
       typically. A grease zerk in the a-arm will get lubrication to the
       outer contact with the a-arm, but not the inner tube
    5. It is perceived as easier to replace the rubber bushings with poly.
       This is true to an extent, as a home mechanic you can carefully cut
       the old bushing housings to collapse and remove them and then
       installation of poly is a breeze. That said to do it properly and
       with access to a hydraulic press (e.g. Horrible Fright $150 unit)
       it isn't that hard to press out the old bushings and press in new.
    6. Cost has been a factor for the Pantera in the past, but Maserati
       Source has made in Italy oem style rubber bushings for $295 a set
       of 16, about the same cost as set of poly bushings from our
       vendors.

   Be aware not all poly bushings are made equal, you might check what
   durometer hardness each vendor is offering as this will affect ride
   quality and harshness. I know Dennis Quella's offerings at one time had
   a round to hex center tube and inner bushing design, that attempted to
   confine one degree of freedom of movement, whether this actually
   provides better performance or not I cannot say.
   Finally , you realize you are going down a rabbit hole..... as at some
   point you need consider your objective along with the suspension system
   working in unison as a whole. The single biggest upgrade I made to the
   performance of my GT5 was installation of 1 inch sway bays front and
   rear. Then there's varying opinion on the sway bar ball ends,
   adjustable shocks, spring rates etc.
   Regards,
   Julian
     __________________________________________________________________

   From: DeTomaso <detomaso-bounces at server.detomasolist.com> on behalf of
   charlesmccall at gmail.com <charlesmccall at gmail.com>
   Sent: Thursday, April 9, 2020 12:30 AM
   To: detomaso at server.detomasolist.com <detomaso at server.detomasolist.com>
   Subject: [DeTomaso] Poly vs. Rubber suspension bushings

   Hi all
   I decided to take advantage of being away from my car to fix a
   long-time engine oil leak by removing my suspension, radiator, etc

   You know how these things go... I asked the guy to check the car over
   while he had the engine out, and the task list is growing, so my car is
   in a bunch of pieces right now.

   Mike Drew is helping source parts for me, and he asked if I wanted poly
   or rubber bushings. I know that this subject has been discussed a
   million times, but I didn't take notes. My specific question:

   1.      Is it commonly accepted that poly is better but will squeak
   without proper lubrication? Rubber is maintenance-free but degrades
   over time and doesn't work quite as well?
   2.      How difficult is it to lubricate them? Is this a matter of
   installing a zerk fitting and zapping it once a year? Do you wipe it
   on? How easy is it to access them without a lift?
   Thank you!


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