To those watching / reading thinking this is a bad thing, keep in mind that road isolation is actually good for grip AND predictability. There is ZERO benefit to feeling every little bump in the road! Your suspension needs to 1) respond to your control inputs, 2) absorb road noise, and 3) dampen larger amplitude motions in a timely fashion that could upset the chassis. This video demonstrates 2) in action: the suspension is absorbing road noise. Interesting that 'real-world roads' are rougher than you realize! Perhaps the rear mounts have more compliance than some would like - I haven't driven this car hard enough to note whether it feels imprecise or not because the rear mounts have designed play. Something HAS to move at higher frequencies or you get a LOT more road noise transmitted from one tire, into the suspension, and conducted into other tires. Think resonance. The shock mount is absorbing this energy so the chassis (and your body, and the other three tires) don't have to. I'd argue that these road features are exactly what you'd want to filter. If you're building an ultra-precise RACE ONLY car then I can see remove more compliance to increase precision. BUT be careful - you might end up with a jittery, bouncy, unstable car at the limit. I've worked with lots of racers who have suffered from lack of confidence and grip when reducing compliance. If you remove compliance from the top mount then yes, the damper works more directly. That would be bad if the damper is very stiff or has a high gas-spring (as MCS/JRZ/Moton/etc do). SEAL DRAG exists and goes UP as you get to a larger diameter piston shaft. At some point your tire sidewalls could become your suspension. Listen to this BMW E46 M3 customer (formerly on MCS 2-ways now on FCM Elite) describe his experience. I know his setup had spherical mounts front and rear, as well: 5 min video - ruclips.net/video/JN95fi-fKHk/видео.html Many people over-utilize dampers to provide 'control' when your first order control comes from selecting spring rates that create Flat Ride (yes, my favorite term). Then you have KEEP Flat Ride through avoiding jacking down or launching, and also choose bump stops that prevent terminal understeer or oversteer. A vehicle with well-chosen Flat Ride-based ride frequencies will transition VERY well even with rather soft low-speed damping (and non-spherical mounts). See my video 'Why Flat Ride Matters: An Amazing Road test with NO damping' and skip to the last half for my reflection on the actual 'no damping' road test. ruclips.net/video/KpTN8Viau-I/видео.html I have >100k mi on pretty worn OE rear rubber mounts (E46 330i), they definitely have a bit of play in them. Andrew and others have driven Christina and she works quite well. In all my track and autocross videos, I've used aged rubber rear mounts. I have a pair of spherical mounts, never gotten around to installing them. if you're trailering your car then by all means, go spherical. But think about where the compliance (i.e. high-frequency energy absorption) in your system is going to come from. If you want more forgiveness and overall grip (especially with supposedly high-end dampers that have HIGH gas springs!) then stick with the OE rear mounts. NO compliance = NO forgiveness. Keep that in mind if you don't want to prematurely age your tires, or fly off the road into the weeds (or a wall)...
Couple things. First and foremost, spherical mounts are meant for track cars. I don't recommend them for purely street cars due to potential maintenance hassles so NVH shouldn't be a major concern for the end user of these mounts. With that said, my customers can't tell the difference in NVH with a top mount swap on a damper that only passes damper rod loads through the spherical and not spring loads while all the other suspension hard points are on rubber bushings as well. Interestingly, on the S60R it solved my rear shake problem though so I can't say it didn't effect NVH for me, it did so in a positive way that increased cornering power. Regarding road isolation being good for grip and predictability: This is only true sometimes. How do we know this? Sometimes, running a cut down main piston wear band can have good effect on low speed corner grip. This floating piston band creates a dead band and cuts out all force passing through the shock for some small displacement as the piston displaces relative to the wear band which limits oil flow only to the rod displaced volume through the bleed circuit. It sounds a bit like your MCU top mount but this is not a universally used option for a reason and most people don't even know its a potential useful trick. Professional teams will learn which tracks see a net benefit from creating this dead band and implement on an as needed basis. However, they can't do that if they don't have a choice with rubber mounts... which no serious track car I've ever seen in my life uses. What I plan to try but have never seen done is running a cut band on a street car which again would only make sense if you eliminated the rubber top mount. Regarding your MCS customer: I don't operate on the philosophy that you should bandaid a bad damper with a rubber mount which is effectively what you're stating. High gas and friction forces can be mitigated through good design and all three of the brands you mentioned are terrible in my experience. That doesn't mean you should be married to the damper and cover up poor performance with another spring in the damping system. You also mention removing compliance would be bad if the damper is very stiff. Again, it depends on your customer. Some drag cars have a few hundred to 1,000lb zero point rebound forces. A rubber mount would negate any benefit of this type of setup and also would likely fail if anyone ever tried it.
@@pdvmotorsports So we agree on spherical being better-suited for track cars. Rubber bushings do absorb a lot of NVH which is something people may miss when going stiffer. I've never tested a cut-down piston band though the effect sounds similar to drilling holes in the piston to create a dead band (i.e. small amplitude, high-frequency filter). I cite my street-driven, track-oriented BMW using rubber rear mounts as an example, not a recommendation for a dedicated race car. The trailered race cars I work commonly use spherical or Delrin. Christina has a GC front Race bar and GC camber plates, poly bushings, and ride frequencies are over 2 Hz. Not plush but rather compliant while still precise. Due to Flat Ride being present, she's eager to turn-in without the dampers having to do a whole lot of work to force that to happen. Quite amazing, really. A drag car with a nearly hydro-locked damper is pretty far from what most need their suspension to do but I understand your example. I think we both know it's common for well-meaning enthusiasts to buy 'high-end' dampers, add spherical bearings or mounts (or stiff sways) then wonder why their ride is rough, even at 'full soft' on the adjusters. They've lost compliance on multiple fronts and now have a punishing car that might be somewhat faster but is less enjoyable and less stable at the limit. A well-designed suspension for your application ought to inspire you up to and over the limit. Seems that's what we're both aiming for.
@@SuspensionTruth I don't think a floating wear band will behave like what you seem to be describing as additional bleed holes. The floating band doesn't add bleed to the low speed circuit so its an independent feature and of course isn't a permanent change to the piston.
On a road car this damper movement is most likely a feature and not a bug. The movement in the top mount ensures high speed movement of the springs in case of high speed (road imperfections) impacts, which are too fast for the slow damper to be able to react to
Another great video. Thanks for taking the time to rig it up! In the vid you allude to it has a rate, but I think it is more like a preload because it is an effort that needs to be overcome before the damper takes affect. I’m speculating that the damper starts working once the extension of the inner rubber mount is exhausted.
You're correct the damper starts working once the mount's flexible material travel is exhausted. As it's extending away from the "normal/at rest" position it would be applying a spring rate of its own since it's now tensioned.
I would put these more to Track-use (your video title is a bit straight). These Rubber bushings and mounts are not like stupid rubber pieces anymore but well-designed and engineered. There was a pretty huge video out of a vist to such a company in Germany, I can try to find it if interested. For Track use no doubt, I would do the same. Thank you for your videos, many are very pro-level explained and helping.
It is not a smart idea to place even suspension with adjustable settings on any stock mount. I want a set of these mounts as well. This is why I am going to use Camber plates on my front as well. Bilstein Clubsports also come with spherical mounts.
Greg, please see my comment above if you haven't yet. The Ohlins seems to have some high-frequency filtering, but it still tends to have somewhat high gas force. That, coupled with a spherical rear mount, would increase NVH and potentially make the rear even less consistent. I've spoken with a number of F80 M3 owners who have trouble getting the rear of their cars to hook up. The tendency to add rebound bias is probably part of the problem with the Ohlins (and most brands).
Yeah, I can imagine 1-2mm of play being good for high frequency filtering, but some of those regular larger displacement movements were concerning to me. Especially when the road didn't look that bumpy!
Indeed! Many modern BMW / Mini and some other OEMs use micro-cellular polyurethane (MCU) bushings in their top mount designs (instead of rubber). The 'air-cell' of the MCU, once loaded, creates a 'region of zero stiffness' which allows road noise to be absorbed vs. a rubber bushing (or a spherical mount). The 'Ripple Reducer' as I coined it for damper modifications, would work over a few mm range, and Andrew's video shows around that for general road features and above that for the larger bumps.
@@FaRKle0079 It's amazing how much a suspension is actually working even on what doesn't appear to be a bumpy road! Clearly, it was and you weren't feeling it. Take care switching to a spherical mount paired with a damper that has HIGH gas force and HIGH low-speed damping (either bump or rebound). As I mentioned privately, some accelerometer-based 'noise' testing would be rather instructive. Plus, doing some slalom-type maneuvers and finding a consistently rough road to gauge total peak-to-peak movement of the damper / strut mount.
Err what he said !^ Thank you,a great insight into a part of the rear suspension I hadn’t even thought of. Superb video Farkle,again. @@SuspensionTruth
To those watching / reading thinking this is a bad thing, keep in mind that road isolation is actually good for grip AND predictability. There is ZERO benefit to feeling every little bump in the road! Your suspension needs to 1) respond to your control inputs, 2) absorb road noise, and 3) dampen larger amplitude motions in a timely fashion that could upset the chassis.
This video demonstrates 2) in action: the suspension is absorbing road noise. Interesting that 'real-world roads' are rougher than you realize! Perhaps the rear mounts have more compliance than some would like - I haven't driven this car hard enough to note whether it feels imprecise or not because the rear mounts have designed play. Something HAS to move at higher frequencies or you get a LOT more road noise transmitted from one tire, into the suspension, and conducted into other tires. Think resonance. The shock mount is absorbing this energy so the chassis (and your body, and the other three tires) don't have to.
I'd argue that these road features are exactly what you'd want to filter. If you're building an ultra-precise RACE ONLY car then I can see remove more compliance to increase precision. BUT be careful - you might end up with a jittery, bouncy, unstable car at the limit. I've worked with lots of racers who have suffered from lack of confidence and grip when reducing compliance.
If you remove compliance from the top mount then yes, the damper works more directly. That would be bad if the damper is very stiff or has a high gas-spring (as MCS/JRZ/Moton/etc do). SEAL DRAG exists and goes UP as you get to a larger diameter piston shaft. At some point your tire sidewalls could become your suspension. Listen to this BMW E46 M3 customer (formerly on MCS 2-ways now on FCM Elite) describe his experience. I know his setup had spherical mounts front and rear, as well:
5 min video - ruclips.net/video/JN95fi-fKHk/видео.html
Many people over-utilize dampers to provide 'control' when your first order control comes from selecting spring rates that create Flat Ride (yes, my favorite term). Then you have KEEP Flat Ride through avoiding jacking down or launching, and also choose bump stops that prevent terminal understeer or oversteer. A vehicle with well-chosen Flat Ride-based ride frequencies will transition VERY well even with rather soft low-speed damping (and non-spherical mounts). See my video 'Why Flat Ride Matters: An Amazing Road test with NO damping' and skip to the last half for my reflection on the actual 'no damping' road test.
ruclips.net/video/KpTN8Viau-I/видео.html
I have >100k mi on pretty worn OE rear rubber mounts (E46 330i), they definitely have a bit of play in them. Andrew and others have driven Christina and she works quite well. In all my track and autocross videos, I've used aged rubber rear mounts. I have a pair of spherical mounts, never gotten around to installing them. if you're trailering your car then by all means, go spherical. But think about where the compliance (i.e. high-frequency energy absorption) in your system is going to come from. If you want more forgiveness and overall grip (especially with supposedly high-end dampers that have HIGH gas springs!) then stick with the OE rear mounts.
NO compliance = NO forgiveness. Keep that in mind if you don't want to prematurely age your tires, or fly off the road into the weeds (or a wall)...
Shaikh hi, could you check your email please?
Couple things. First and foremost, spherical mounts are meant for track cars. I don't recommend them for purely street cars due to potential maintenance hassles so NVH shouldn't be a major concern for the end user of these mounts. With that said, my customers can't tell the difference in NVH with a top mount swap on a damper that only passes damper rod loads through the spherical and not spring loads while all the other suspension hard points are on rubber bushings as well. Interestingly, on the S60R it solved my rear shake problem though so I can't say it didn't effect NVH for me, it did so in a positive way that increased cornering power.
Regarding road isolation being good for grip and predictability: This is only true sometimes. How do we know this? Sometimes, running a cut down main piston wear band can have good effect on low speed corner grip. This floating piston band creates a dead band and cuts out all force passing through the shock for some small displacement as the piston displaces relative to the wear band which limits oil flow only to the rod displaced volume through the bleed circuit. It sounds a bit like your MCU top mount but this is not a universally used option for a reason and most people don't even know its a potential useful trick. Professional teams will learn which tracks see a net benefit from creating this dead band and implement on an as needed basis. However, they can't do that if they don't have a choice with rubber mounts... which no serious track car I've ever seen in my life uses. What I plan to try but have never seen done is running a cut band on a street car which again would only make sense if you eliminated the rubber top mount.
Regarding your MCS customer: I don't operate on the philosophy that you should bandaid a bad damper with a rubber mount which is effectively what you're stating. High gas and friction forces can be mitigated through good design and all three of the brands you mentioned are terrible in my experience. That doesn't mean you should be married to the damper and cover up poor performance with another spring in the damping system. You also mention removing compliance would be bad if the damper is very stiff. Again, it depends on your customer. Some drag cars have a few hundred to 1,000lb zero point rebound forces. A rubber mount would negate any benefit of this type of setup and also would likely fail if anyone ever tried it.
@@pdvmotorsports So we agree on spherical being better-suited for track cars. Rubber bushings do absorb a lot of NVH which is something people may miss when going stiffer.
I've never tested a cut-down piston band though the effect sounds similar to drilling holes in the piston to create a dead band (i.e. small amplitude, high-frequency filter).
I cite my street-driven, track-oriented BMW using rubber rear mounts as an example, not a recommendation for a dedicated race car. The trailered race cars I work commonly use spherical or Delrin. Christina has a GC front Race bar and GC camber plates, poly bushings, and ride frequencies are over 2 Hz. Not plush but rather compliant while still precise. Due to Flat Ride being present, she's eager to turn-in without the dampers having to do a whole lot of work to force that to happen. Quite amazing, really.
A drag car with a nearly hydro-locked damper is pretty far from what most need their suspension to do but I understand your example. I think we both know it's common for well-meaning enthusiasts to buy 'high-end' dampers, add spherical bearings or mounts (or stiff sways) then wonder why their ride is rough, even at 'full soft' on the adjusters. They've lost compliance on multiple fronts and now have a punishing car that might be somewhat faster but is less enjoyable and less stable at the limit.
A well-designed suspension for your application ought to inspire you up to and over the limit. Seems that's what we're both aiming for.
@@georgesalepis9837 Hi George yes I saw your message come in, I'll reply shortly.
@@SuspensionTruth I don't think a floating wear band will behave like what you seem to be describing as additional bleed holes. The floating band doesn't add bleed to the low speed circuit so its an independent feature and of course isn't a permanent change to the piston.
Great experiment Farkle excited to see the difference with the new top mounts!
And try a few other dampers as well!
Great job as always..
Thank you.
On a road car this damper movement is most likely a feature and not a bug.
The movement in the top mount ensures high speed movement of the springs in case of high speed (road imperfections) impacts, which are too fast for the slow damper to be able to react to
Another great video. Thanks for taking the time to rig it up!
In the vid you allude to it has a rate, but I think it is more like a preload because it is an effort that needs to be overcome before the damper takes affect. I’m speculating that the damper starts working once the extension of the inner rubber mount is exhausted.
You're correct the damper starts working once the mount's flexible material travel is exhausted. As it's extending away from the "normal/at rest" position it would be applying a spring rate of its own since it's now tensioned.
I would put these more to Track-use (your video title is a bit straight). These Rubber bushings and mounts are not like stupid rubber pieces anymore but well-designed and engineered.
There was a pretty huge video out of a vist to such a company in Germany, I can try to find it if interested.
For Track use no doubt, I would do the same.
Thank you for your videos, many are very pro-level explained and helping.
Awesome video FaRKle0079, can I ask what your suspension/ coil over setup is?
This vehicle has a Fat Cat Motorsports custom suspension (completely reworked Bilstein B14) with 265lbs/in front springs and 900lbs/in rear springs.
I'll bet your NVH will increase. You will feel every bump.
It is not a smart idea to place even suspension with adjustable settings on any stock mount. I want a set of these mounts as well. This is why I am going to use Camber plates on my front as well. Bilstein Clubsports also come with spherical mounts.
Shperical not add nvh? Which brand best?
Have you installed it? How's the ride quality impacted? I'm a bit worried about NVH increase
They've been ordered, but I'm still waiting for them to arrive.
I have a f80 with ohlins road and track. I will be buying a pair if you recommend them
Greg, please see my comment above if you haven't yet. The Ohlins seems to have some high-frequency filtering, but it still tends to have somewhat high gas force. That, coupled with a spherical rear mount, would increase NVH and potentially make the rear even less consistent. I've spoken with a number of F80 M3 owners who have trouble getting the rear of their cars to hook up. The tendency to add rebound bias is probably part of the problem with the Ohlins (and most brands).
Looks like "ripple reducer" to me!
Yeah, I can imagine 1-2mm of play being good for high frequency filtering, but some of those regular larger displacement movements were concerning to me. Especially when the road didn't look that bumpy!
Indeed! Many modern BMW / Mini and some other OEMs use micro-cellular polyurethane (MCU) bushings in their top mount designs (instead of rubber). The 'air-cell' of the MCU, once loaded, creates a 'region of zero stiffness' which allows road noise to be absorbed vs. a rubber bushing (or a spherical mount). The 'Ripple Reducer' as I coined it for damper modifications, would work over a few mm range, and Andrew's video shows around that for general road features and above that for the larger bumps.
@@FaRKle0079 It's amazing how much a suspension is actually working even on what doesn't appear to be a bumpy road! Clearly, it was and you weren't feeling it. Take care switching to a spherical mount paired with a damper that has HIGH gas force and HIGH low-speed damping (either bump or rebound). As I mentioned privately, some accelerometer-based 'noise' testing would be rather instructive. Plus, doing some slalom-type maneuvers and finding a consistently rough road to gauge total peak-to-peak movement of the damper / strut mount.
Err what he said !^
Thank you,a great insight into a part of the rear suspension I hadn’t even thought of.
Superb video Farkle,again. @@SuspensionTruth
Hi. We are a dash cam company and want to collaborate with you. How can I reach you? Thanks
Hi, you can reach me at farkle0079@gmail.com. Thanks.
Do u have an Instagram? I have some questions
You can message me at farkle_tech on IG.