RLCA Help: Spherical Bearing vs. Poly Bushing

[MICHPP2]

I've been looking at the BMR BK081 spherical bearing for my RLCA, Lethal puts it in their BMR suspension packages and Steeda has a very similar design to their RLCA bearing, but now I've learned that Superpro offers a polyurethane bushing for the RLCA, and at a cheaper cost.

Could anyone tell me if there would be a difference in NVH between the two? Any difference in actual performance under spirited and normal driving conditions?

I know I can't go wrong either way as long as I get rid of the OE rubber bushing, I just want to make the best decision.

EDIT: I mainly drive the Mustang on spirited cruises and short trips and will take an occasional track day when I get the chance if that factors in anywhere.

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[Bluemustang]

IMO you can't go wrong either way but the poly bushing should be a little better at NVH. I doubt if you feel the difference between the two handling wise. I don't know for sure, just adding my amateur opinion not facts. I don't know of anyone who has tried the Superpro bushing yet. @SAY WHAT is about to, along with some other suspension bits. Maybe he can chime in on his experience after it is installed.

 

[NightmareMoon]

I didn’t really notice any NVH increase going to the sphericals. Probably can’t go wrong either way.

 

[Norm Peterson]

If there is much of any off-axis rotation at this pivot location, polyurethane really isn't the right material for the job.


Norm

 

[ahl395]

No NVH from my spherical bearings and a huge improvement in traction and stability on hard acceleration.

I'd just stick with the spherical IMO, tried and trusted brand/product, and I would imagine if there's any difference the poly would deflect a little more and likely less improvement.

 

[Brian@BMVK]

If there is much of any off-axis rotation at this pivot location, polyurethane really isn't the right material for the job.


Norm

Normally I'd completely agree, though in this case it looks like they've designed it to take some off-axis rotation.

Spherical is tough to beat and so, so good for the performance.

 

[Brian@BMVK]

I'd do the BK055. Biggest bearing

 

[MICHPP2]

Normally I'd completely agree, though in this case it looks like they've designed it to take some off-axis rotation.

Spherical is tough to beat and so, so good for the performance.

I've recently read that the spherical bearing on the RLCA removes damping and sends those vibrations to the shocks, which would lead to more bounciness with the RLCA bearing.

Do you think that the poly bushing would allow some of the damping that the OE rubber bushing provides and therefore less bounciness than the spherical bearing?

 

[Brian@BMVK]

I've recently read that the spherical bearing on the RLCA removes damping and sends those vibrations to the shocks, which would lead to more bounciness with the RLCA bearing.

Do you think that the poly bushing would allow some of the damping that the OE rubber bushing provides and therefore less bounciness than the spherical bearing?

There's only one company saying that. Let that sink in...

The bushing acts far, far more like a spring than a damper in the direction the shock acts in, and it does so in undesirable ways. It resists the spring pushing the inside tire down like a bigger swaybar, but also acts in two wheel simultaneous bumps just like even stiffer springs do. It most definitely does not cause what's claimed. I remember being delighted with the fact that my ride actually improved noticeably with the bearings because they were no longer adding ~80-100 lb/in of wheel rate. Having a bearing there does make sharper road impacts both more noticeable and in particular, audible, because there's no longer rubber to deflect from the longitudinal forces.

 

[Norm Peterson]

Normally I'd completely agree, though in this case it looks like they've designed it to take some off-axis rotation.

Could be, if they actually look more like this. Seems it's the Aussie companies that pay enough attention to what's really going on in a compliant bushing to sneak in some compliance.

Norm

 

[Brian@BMVK]

Could be, if they actually look more like this. Seems it's the Aussie companies that pay enough attention to what's really going on in a compliant bushing to sneak in some compliance.

Norm

They do indeed look that way.

 

[SAY WHAT]

Want me to send you guys a clip of those super pro bushings? I have them setting in a box right now.

 

[Norm Peterson]

Sure. Maybe try to find out how deep those circumferential grooves are.


Norm

 

[SAY WHAT]

That’s what I got! If you are talking about how far the poly protrudes out, it’s about 1/2inch.

 

[TeeLew]

Has anyone had the Energy Suspension version in their hands? From the installation pictures it appears to be a 3-piece bushing which essentially makes a polyurethane spherical to accommodate off-axis motion. I haven't actually handled one, though, so maybe I'm giving it undue credit.

I haven't seen excessive NVH problems running sphericals on the street, but they are a maintenence item which will need to be changed due to wear and/or corrosion from time to time. They will eventually wear, loosen up and develop lash. In cold/wet climates, you might have to deal with corrosion problems depending on the quality of the monoball you're using.

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