SuperPro Bushings back in stock at C&S!!!

[Prez1967]

https://www.corvettepartscenter.com/...on-bushing-kit

I know a bunch of you have been waiting

[Hib Halverson]

The advertisement at that link says:

Better than rubber, and far better than polyurethane.

I visited the "Super Pro Suspension Parts" web site and it says about the material used in the company's bushings:

The base material used by SuperPro is a polyurethane elastomer

and

SuperPro polyurethane suspension bushes are not copies of the OE rubber components. They are specially developed from the ground-up to take advantage of this material?s unique properties. Polyurethane bushes by SuperPro are unique as they are the only polyurethane products fully backed Design-Engineered?Manufac (sic) by a professional research and development program with many years of hands-on experience in the automotive suspension industry.

So..."Prez1967" how can Super Pro bushings be "better than polyurethane if they are, in fact, polyurethane?

My experience with Polyurethane control arm bushings has been that, unless they are graphite-impregnated, at best, they will squeak in cool, damp weather and may squeak all the time. I've even had graphite-inpregnated urethane bushings squeak when driven in cold, wet weather.

For a C4, ZR1 or otherwise, which is a show car, waxer or just a "driver" there is not reason to use anything other than OE rubber or good quality rubber replacements.

Now if you are an aggressive street driver or a track rat, obviously you want control arm bushings with less compliance. In that case, there are three choices.

At the low end of the price range and the ease-of-installation range, you have polyurethane. If you go that route, the only way to go if the C4 is both street and track, is graphite-impregnated urethane in the front control arms.

The second choice would be a track-only option and that is replacing front bushings with metallic control arm bearings and rear bushings with spherical bearings. The cost is, obviously, more than urethane, but you'll have zero compliance at the control arm pivot points. Metallic suspension bearings transmit all road noise and harshness to the chassis and into the interior so, while they can by used on the street, you'd better be ready for a lot of noise and teeth-chattering harshness.

The third choice is the delrin/aluminum composite suspension bearing marketed by Global West Suspension in the front control arms. You get a significant reduction in compliance compared to rubber and an additional slight reduction in compliance compared to urethane. Global's "Del-Alum" parts never squeak because they have lube fittings. The "Del-Alum" also is a suspension bearing not a bushing. Lastly, it has a very slight amount of compliance which mitigates noise and harshness to a certain extent.

With one exception, every car to which I've installed aftermarket control arm "bushings" has been equipped with the Global West Del-Alum. The only exception was a Datsun 510 and a Chevy Beretta I once owned. At the time, Global did not have a Del-Alum design either application. The Del-Alum also has pretty darn good durability as long as they are lubed every so often. I had a set on the '65 Malibu project car I owned from the late-70s until 2012. It's Del-Alums had over 100,000 miles on them with no adverse wear.

With all that said, there are still going to be some C4 owners who will insist on urethane. If that's the case, keep in mind that you can only use polyurethane in the front control arms, the stabilizer bar mounts, the stabilizer bar links, the damper mounts and the rear spring insolators.

Do not use poly in the rear trailing arms or the strut rods because, as the C4 suspension moves, those parts rotate and well as moving vertically. Polyurethane is so stiff that it resists the normal rotation of those parts causing the rear suspension to bind as it nears the ends of its travel. Worse yet, with urethane in the rear arms, the suspension rate is not consistent. Because the more a urethane-bushed rear arm rotates, the more the urethane resists that rotation, the car is less predictable driven at the limit. This is especially true at corner entry and corner exit. Bottom line, in the C4 rear, you need to use either stock rubber or spherical bearings. Neither Urethane nor even the fabled Global West Del-Alum should not be used in C4 rear arms.

[Prez1967]

Originally Posted by Hib Halverson

The advertisement at that link says:I visited the "Super Pro Suspension Parts" web site and it says about the material used in the company's bushings:
and
So..."Prez1967" how can Super Pro bushings be "better than polyurethane if they are, in fact, polyurethane?

My experience with Polyurethane control arm bushings has been that, unless they are graphite-impregnated, at best, they will squeak in cool, damp weather and may squeak all the time. I've even had graphite-inpregnated urethane bushings squeak when driven in cold, wet weather.

For a C4, ZR1 or otherwise, which is a show car, waxer or just a "driver" there is not reason to use anything other than OE rubber or good quality rubber replacements.

Now if you are an aggressive street driver or a track rat, obviously you want control arm bushings with less compliance. In that case, there are three choices.

At the low end of the price range and the ease-of-installation range, you have polyurethane. If you go that route, the only way to go if the C4 is both street and track, is graphite-impregnated urethane in the front control arms.

The second choice would be a track-only option and that is replacing front bushings with metallic control arm bearings and rear bushings with spherical bearings. The cost is, obviously, more than urethane, but you'll have zero compliance at the control arm pivot points. Metallic suspension bearings transmit all road noise and harshness to the chassis and into the interior so, while they can by used on the street, you'd better be ready for a lot of noise and teeth-chattering harshness.

The third choice is the delrin/aluminum composite suspension bearing marketed by Global West Suspension in the front control arms. You get a significant reduction in compliance compared to rubber and an additional slight reduction in compliance compared to urethane. Global's "Del-Alum" parts never squeak because they have lube fittings. The "Del-Alum" also is a suspension bearing not a bushing. Lastly, it has a very slight amount of compliance which mitigates noise and harshness to a certain extent.

With one exception, every car to which I've installed aftermarket control arm "bushings" has been equipped with the Global West Del-Alum. The only exception was a Datsun 510 and a Chevy Beretta I once owned. At the time, Global did not have a Del-Alum design either application. The Del-Alum also has pretty darn good durability as long as they are lubed every so often. I had a set on the '65 Malibu project car I owned from the late-70s until 2012. It's Del-Alums had over 100,000 miles on them with no adverse wear.

With all that said, there are still going to be some C4 owners who will insist on urethane. If that's the case, keep in mind that you can only use polyurethane in the front control arms, the stabilizer bar mounts, the stabilizer bar links, the damper mounts and the rear spring insolators.

Do not use poly in the rear trailing arms or the strut rods because, as the C4 suspension moves, those parts rotate and well as moving vertically. Polyurethane is so stiff that it resists the normal rotation of those parts causing the rear suspension to bind as it nears the ends of its travel. Worse yet, with urethane in the rear arms, the suspension rate is not consistent. Because the more a urethane-bushed rear arm rotates, the more the urethane resists that rotation, the car is less predictable driven at the limit. This is especially true at corner entry and corner exit. Bottom line, in the C4 rear, you need to use either stock rubber or spherical bearings. Neither Urethane nor even the fabled Global West Del-Alum should not be used in C4 rear arms.

I appreciate the write up.

I was considering going full spherical bearings on the suspension as thats what i'm running in my Fox Mustang and used similar in a 996 C2 build a couple years back. I have no issue with driving them on the street but figured since I already have a "track car" I can build this into more of a GT cruiser.

Its my understanding that OEM style rubber bushings are no longer made.

Ive talked to some local owners that have alot of success with these SuperPro bushings and since they have been around alot longer than me, I'll give it a shot. Hard to beat for the price and since I have a press at home, it only costs me $408 IIRC

I really really wanted to go full RideTech with coilovers, arms, bars, etc but that shifts the cars purpose.

[Jagdpanzer]

Originally Posted by Jagdpanzer

Hib, Thank you for sharing your first hand experiences with the alternative suspension bushings types you've discussed above.
Several years back I replaced all of the rear suspension bushings on my 94 with a leading brand of graphite impregnated polyurethane bushings. These turned out to be significantly stiffer than the stock OEM rubber bushings they replaced. I'm mostly a street guy and was very disappointed in the increased road noice and ride harshness they caused. Adding insult to injury they eventually started squeaking. So started looking for something better. 25 year old rubber bushings in the front suspension was also beginning to concern me. If freshly made OEM rubber bushings were available I would have gladly gone in that direction however, as we know, this is no longer the case(if they ever was).
Last summer I came across SuperPro bushings for C4 Corvettes and after doing some investigating decided to give them a try.
Here is my experience. SuperPro polyurethane material is some tough stuff but much more compliant than the hard graphite impregnated polyurethane bushings I had installed before. Their design and construction is also more sophisticated. Because of the more compliant material they are one piece construction which can be pressed in whole and not two piece like the previous hard construction polyurethane urethane bushings. Also the bushing inner bores have deep knurled surfaces machined in them to help retain lubricant. All bushings came with precision made nickel plated steel inserts which pivot within the lubricated polyurethane bushings. After torquing to spec the rear trailing arms and strut rods are firmly retained yet free to rotate without binding as you've observed with other polyurethane bushings. I have a little over 2k miles on these since installing and so far l'm very pleased with the results for the goals I had set out of minimizing road noice and ride harshness while retaining firm handling characteristics. And NO SQEAKS!!

60702412082__563A53D9-3E22-4F5C-83D4-029C8A0BFA11.JPG

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[Hib Halverson]

Originally Posted by Jagdpanzer

Hub, Thank you for sharing your first hand experiencesAttachment 13408 with the alternative suspension bushings types you've discussed above.
Several years back I replaced all of the rear suspension bushings on my 94 with a leading brand of graphite impregnated polyurethane bushings. These turned out to be significantly stiffer than the stock OEM rubber bushings they replaced. I'm mostly a street guy and was very disappointed in the increased road noice and ride harshness they caused. Adding insult to injury they eventually started squeaking. So started looking for something better. 25 year old rubber bushings in the front suspension was also beginning to concern me. If freshly made OEM rubber bushings were available I would have gladly gone in that direction however, as we know, this is no longer the case(if they ever was).
Last summer I came across SuperPro bushings for C4 Corvettes and after doing some investigating decided to give them a try.
Here is my experience. SuperPro polyurethane material is some tough stuff but much more compliant than the hard graphite impregnated polyurethane bushings I had installed before. Their design and construction is also more sophisticated. Because of the more compliant material they are one piece construction which can be pressed in whole and not two piece like the previous hard construction polyurethane urethane bushings. Also the bushing inner bores have deep knurled surfaces machined in them to help retain lubricant. All bushings came with precision made nickel plated steel inserts which pivot within the lubricated polyurethane bushings. After torquing to spec the rear trailing arms and strut rods are firmly retained yet free to rotate without binding as you've observed with other polyurethane bushings. I have a little over 2k miles on these since installing and so far l'm very pleased with the results for the goals I had set out of minimizing road noice and ride harshness while retaining firm handling characteristics. And NO SQEAKS!!



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Did you disconnect the spring and work the suspension through its full travel to determine the rear arms could rotate and not bind up?

I thought you mentioned "lubrication". Do the Super Pro bushings have lube fitttings? Or, do they come with a plastic pouch of lube you squeeze into them during the installation process?


Finally, my name is "Hib" not "Hub".

[Jagdpanzer]

Originally Posted by Hib Halverson

Did you disconnect the spring and work the suspension through its full travel to determine the rear arms could rotate and not bind up?

I thought you mentioned "lubrication". Do the Super Pro bushings have lube fitttings? Or, do they come with a plastic pouch of lube you squeeze into them during the installation process?


Finally, my name is "Hib" not "Hub".

Yes, before reconnecting the spring I worked the suspension through its full travel and found no noticeable binding.

Yes, they came with plastic pouches of a silicone like lubricant which was applied during assembly. At the time I had thought about adding lube fittings but decided to first see how effective the knurled inner bore surfaces were at long term lube retention. However, if proved inadequate I plan to add lube fittings. Probably through small diameter drilling's in the retaining bolts and inner steel inserts.

Sorry about the typo. After first posting I immediately noticed the error and attempted to correct it but for some reason l was not fully successful using the IPhone app. Hopefully it worked this time.

[Ccmano]

I only see the rear control arm and batwing bushings on the SuperPro site. I'm not seeing the dog bone bushings. Do they provide those?
H

[Jagdpanzer]

Funny, I noticed the same thing on the main SuperPro site when I first started researching these last summer.
Photo on Corvette Parts Center shows them all except for the batwing.
https://www.corvettepartscenter.com/...on-bushing-kit


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[Jagdpanzer]

Here is their batwing bushing listing
https://www.corvettepartscenter.com/...nt-bushing-set


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[Ccmano]

Thanks Phil. I wonder if you can buy the dog bone bushings alone?
H