Spherical bearings
07-21-2015, 10:39 AM
#1
Boost Pope
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Spherical bearings
Some coilover packages include upper mounts which use a spherical bearing to receive the shock rod, as opposed to a rubber bushing. Manufacturers commonly refer to these as "pillowball" mounts, and they can also be purchased as standalone items from certain vendors such as FM.
Various claims are made that these devices improve the response of the shock absorber, contribute to NVH, etc.
Discuss.
Various claims are made that these devices improve the response of the shock absorber, contribute to NVH, etc.
Discuss.
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07-21-2015, 11:45 AM
#3
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Yes.
Is it significant in a miata? Meh.
Having run fancy coilovers with rubber and pillow *****, I didn't really notice a significant degradation in the ride quality.
BUT
if you do swap out NB2 shocks, make sure you get the little clear plastic gaskets that go between the body and shock top to prevent the squeaks.
Is it significant in a miata? Meh.
Having run fancy coilovers with rubber and pillow *****, I didn't really notice a significant degradation in the ride quality.
BUT
if you do swap out NB2 shocks, make sure you get the little clear plastic gaskets that go between the body and shock top to prevent the squeaks.
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07-21-2015, 01:23 PM
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Yes. As the lower control arm cycles, the angle between the shock and the upper shock mount must change slightly. A spherical bearing allows this angle to change without applying any substantial side load to the shock shaft. A rubber bushing will apply a side load which increases stiction in the shock and thus reduces response.
The same metal bearing that allows ideal articulation of the shock will transmit more force to the chassis, which will increase NVH
contribute to NVH
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07-24-2015, 06:54 PM
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Yes. As the lower control arm cycles, the angle between the shock and the upper shock mount must change slightly. A spherical bearing allows this angle to change without applying any substantial side load to the shock shaft. A rubber bushing will apply a side load which increases stiction in the shock and thus reduces response.
The same metal bearing that allows ideal articulation of the shock will transmit more force to the chassis, which will increase NVH
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07-25-2015, 07:05 AM
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I only have one direct comparison, meaning same car, same basic set-up, only the mount style was changed.
Had a guy running Ohlins on his NC for trackdays. Eventually his spherical bearings started making NVH noise over bumps that was pretty noticeable. Sounded like the struts were loose in their top mounts going over bumps. The bearings had some play in their races.
Ohlins sent us new spherical bearings, but they were even louder. Sent them back, tried the next set they sent us. Still loud. Ohlins said that's the best it was going to get, the bearings were within spec. It was weird, because the first set was quiet for a good while.
The owner still drove the car on the road, and didn't like the extra noise, so we adapted his original squishy rubber mounts.
Driving it around the back roads, I could tell no difference. Owner says he can feel no difference on track. I'm sure the difference is small, but demonstrable.
Race car = pillowball
Street car = personal preference of NVH vs. performance.
Had a guy running Ohlins on his NC for trackdays. Eventually his spherical bearings started making NVH noise over bumps that was pretty noticeable. Sounded like the struts were loose in their top mounts going over bumps. The bearings had some play in their races.
Ohlins sent us new spherical bearings, but they were even louder. Sent them back, tried the next set they sent us. Still loud. Ohlins said that's the best it was going to get, the bearings were within spec. It was weird, because the first set was quiet for a good while.
The owner still drove the car on the road, and didn't like the extra noise, so we adapted his original squishy rubber mounts.
Driving it around the back roads, I could tell no difference. Owner says he can feel no difference on track. I'm sure the difference is small, but demonstrable.
Race car = pillowball
Street car = personal preference of NVH vs. performance.
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07-25-2015, 10:45 PM
#8
My car is still on nb mounts. Billet uppers is another one of those things where the theory guy in my head is yelling about it being better and the right way to go, but the guy who actually makes **** and does things is pretty sure that I have an enormous list of other stuff to spend that money and/or time on to make the car faster. If I was going to buy a new shock setup now would I drop he extra money on it? Probably. But I'm not going to go out of my way to put a set on my current xidas.
Sharky, you need to have your friend measure those sphericals and then buy the same size from NHBB. NHBB sells the only sphericals with actual thrust load testing done on them, aurora only gives you a rule of thumb based on the radial load rating, NHBB gives you an axial load rating on some of them.
Sharky, you need to have your friend measure those sphericals and then buy the same size from NHBB. NHBB sells the only sphericals with actual thrust load testing done on them, aurora only gives you a rule of thumb based on the radial load rating, NHBB gives you an axial load rating on some of them.
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08-02-2015, 03:39 PM
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When I first got me NA it was running stock squishy upper mounts with lowering springs and stock bilsteins. I was shooting for a more race prep type setup and went with ebay coilover sleeves on the bilsteins with some 2.5" QA1 springs (450 front 350 rear). The stock mounts don't work well with this setup so I designed a top hat that would accept a 2.5" spring and a spherical on top of the damper. Below are some pictures. The tabs have two holes for ride height adjustment (untested bc lazy in winter) but this keeps the piston in the center of the damper for full range of travel. As far as NVH goes this setup is far more rigid than before and "response" is improved, but I actually notice a lot less noise. This could be from my lack of bottoming out over everything, but after this setup I will never go back to what I was running before. For those wondering I have put ~10,000 miles on these with no issues.
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08-03-2015, 02:54 PM
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Curious. Mustangs use caster/camber plates that have the top of the strut through the spherical bearing.
Example pic below, no strut installed, to show bearing clearly.
Example pic below, no strut installed, to show bearing clearly.
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08-04-2015, 12:12 PM
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Interesting...
Given how enormous and expensive the Mustang has gotten over the years, I find it difficult to imagine that packaging constraints or cost dictated the change to strut suspension as opposed to the traditional double A-arm.
Given how enormous and expensive the Mustang has gotten over the years, I find it difficult to imagine that packaging constraints or cost dictated the change to strut suspension as opposed to the traditional double A-arm.
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