Why spherical bearings for A arms
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Intermediate
Joined: Feb 2008
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Why spherical bearings for A arms
I'm considering a bushing upgrade. One thing I've been wondering is why are spherical bearings even an option. Shouldn't an a arm only move in one axis? I can see the a joint moving in more that one axis if there is some flex in the A arm but I cant seem to picture any scenario where a spherical bearing avoids bind over a cylindrical bushing.
Race Director
Joined: Dec 2013
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Don't do it, hence Ferrari went to spherical bushings, and they have to be change out as part of its yearly servicing since they wear out that fast.
So poly bushings all around so the ride is not like a tank for the street use and road course use,
And on the lower rear A arm bushings, prefer to chuck them up in a lathe to bore and SS sleeve about half the poly out of them, so they have less defection.
So poly bushings all around so the ride is not like a tank for the street use and road course use,
And on the lower rear A arm bushings, prefer to chuck them up in a lathe to bore and SS sleeve about half the poly out of them, so they have less defection.
Race Director
Joined: Dec 2013
Posts: 12,505
Likes: 3,631
The problem on the spherical bushings, is on rougher roads that most of America has now since road maintenance funding has fallen way behind, is the sperical bushings do not last long when they are seeing that amount of pounding day in and day out.
Hell, even on smoother high speed road course, you jump the inner apex curb enough on the way in or out, and you can hammer them out of shape in a matter of a event or two as well.
So not saying that spherical bushings are not the Cats Meow, but for what most will be using the Vet for in the first place, just adds major cost of having to keep replacing them as they peen wear out a lot sooner, over the poly bushings instead. And as for the lower rear a arm bushing, for most, the thicker bushing works fine, but if your looking for a step closer to spherical bushing performance (that will last longer), the bushing does need to be reamed with SS insert, to reduce the amount of deflection that even the poly bushing still has there.
Hell, even on smoother high speed road course, you jump the inner apex curb enough on the way in or out, and you can hammer them out of shape in a matter of a event or two as well.
So not saying that spherical bushings are not the Cats Meow, but for what most will be using the Vet for in the first place, just adds major cost of having to keep replacing them as they peen wear out a lot sooner, over the poly bushings instead. And as for the lower rear a arm bushing, for most, the thicker bushing works fine, but if your looking for a step closer to spherical bushing performance (that will last longer), the bushing does need to be reamed with SS insert, to reduce the amount of deflection that even the poly bushing still has there.
Race Director
Joined: Sep 1999
Posts: 12,439
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From: CONCORD NC
when you align these cars, each control arm has 2 mounting points, and each mounting point has 2 adjustment points. Depending on the differential between the adjustment points, a normal cylindrical bushing can get pretty bound up (delrin and poly in particular). In a perfect world a spherical would eliminate this.
I know people that have run them successfully, but I don't have personal experience with their durability
I know people that have run them successfully, but I don't have personal experience with their durability
Safety Car
Joined: Nov 2013
Posts: 3,579
Likes: 1,108
From: Ex DPRK, now just N of Medford, OR
Re: Spherical bearings V. ride quality and longevity:
I have a stock C5 with poly bushings and a C6Z with LG Bilstein coilovers and full spherical bearing suspension.
The C5 rides like an oxcart. Zero difference in ride quality between the stock rubber bushings and the urethane .
The Z rides like a big fluffy Caddy in comparison. If it wasn't so low, I'd road trip it anywhere.
Monoballs start to rattle when they wear out, but they're pretty easy to replace.
AMT uses a high-dollar one, and they claim a long lifespan...
I have a stock C5 with poly bushings and a C6Z with LG Bilstein coilovers and full spherical bearing suspension.
The C5 rides like an oxcart. Zero difference in ride quality between the stock rubber bushings and the urethane .
The Z rides like a big fluffy Caddy in comparison. If it wasn't so low, I'd road trip it anywhere.
Monoballs start to rattle when they wear out, but they're pretty easy to replace.
AMT uses a high-dollar one, and they claim a long lifespan...
Premium Supporting Vendor
Joined: Sep 2017
Posts: 1,457
Likes: 657
From: DFW Texas
My personal opinion is that Monoballs give a better driving experience. They are geared toward track use but it takes away a steering disconnect/numbness feel and gives you a more connected/accurate feel on both street and track. You will feel the reflective bumps in between lanes more and the rumble strips on the shoulder of the highway are decidedly more pronounced. I still prefer the improved feel and accuracy over situational NVH.
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Racer
Joined: Sep 2009
Posts: 464
Likes: 215
From: Olmsted Falls, OH (Cleveland)
2023 C2 of the Year Finalist - Unmodified
I run GSpeed spherical and their coilovers setup. The thing handles like a go cart.
Ask yourself what you want to do with the car. Admittedly, they are a little harsh for the street. If I was to do it over again, I would do Delrin or poly bushing setup. Track handling would diminish, but street driving would be more comfortable.
One thing; if you go with a higher quality product like Gspeed or AMT, they use better materials and I don’t think they experience the wear issue that other setups may suffer (rebuilds). I’ve had no issues or squeak with mine.
im pretty happy with the setup. I live with the street manners because the trade off is worth it. I do approx 5-6 track days per year. Street miles around 1500/year.
Ask yourself what you want to do with the car. Admittedly, they are a little harsh for the street. If I was to do it over again, I would do Delrin or poly bushing setup. Track handling would diminish, but street driving would be more comfortable.
One thing; if you go with a higher quality product like Gspeed or AMT, they use better materials and I don’t think they experience the wear issue that other setups may suffer (rebuilds). I’ve had no issues or squeak with mine.
im pretty happy with the setup. I live with the street manners because the trade off is worth it. I do approx 5-6 track days per year. Street miles around 1500/year.
Racer
Joined: Sep 2009
Posts: 464
Likes: 215
From: Olmsted Falls, OH (Cleveland)
2023 C2 of the Year Finalist - Unmodified
Also, spherical will limit any fore/aft movement of the arm. It takes ALL of the “slop” out of a bushing setup.
Last edited by blckss; Aug 31, 2023 at 07:55 AM.