RLCA Help: Spherical Bearing vs. Poly Bushing

[Radiation Joe]

Just ordered the Steeda tension links with bearings. Included the toe link to knuckle bearings for good measure. Most of my suspension front and rear is going to be spherical bearings in about 3 weeks. I'll report back then.

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[KellTrac]

@KellTrac I respect your experience in this area and have valued your opinion on chassis setup over the years both as the proprietor of your new business and your former employment with another well respected business here on the forums. With that, please allow me to ask for some further clarification for myself and others on this thread.

First of all, it's safe to assume most people interested in going the bushing route over the bearing are primarily street driven cars. Moderate horsepower and most likely driven daily with the occasional trip to the strip or HPDE event but not primarily track cars. In this instance the bearing route comes with the possible drawbacks of NVH and replacement frequency that may concern people on a car that is used under the above circumstances. With the bushing, you may sacrifice most of the positive locating properties of the bearing but you still get some of that and you still get the free articulation that is not afforded to you with the factory bushing. In your opinion, is that not enough to justify the use of the bushing over the OEM unit? Or am I incorrect in any of my above assumptions?

Hi @Jaymar - thank you for the kind words.

Having been around this stuff and involved with developing products and catering to the end users for close to 20 years now, I can confidently express these opinions and as I stated, call a spade a spade. So that being said, let me explain my reasoning.

The stock bonded rubber bushing is not a great design for optimal performance. However, it DOES it's job. I should say, the "system" does it's job. Due to the rear bushing on the RLCA being a "spherical monoball" style, it does help the situation by only allowing the front pivot point to pivot and not push and totally distort.

When talking about replacing this specific part, we talk about a very involved job. So naturally I think it is best to suggest the best product for the work and cost involved.

When talking about poly vs Rubber. Meh. Sure, the poly design will have a "free floating" inner sleeve, but it is also off plane on rotation pivot so it will have a free moving range then it will stiffen as it pivots as it becomes unseated from its natural position.

When you cycle polyurethane like that it is very very very common to have what I call "cold flow" which is the material breaking down and deforming. This is very common with these sort of applications. NOW, that said, SuperPro has some excellent materials. Spades....their bushing designs and materials FAR EXCEED the quality of the Energy offerings from my very extensive experience with each company.

When we talk NVH. Poly is great....when it is great. lol. I realize these companies have these mesh interiors of their bushings as can be seen in earlier photos. That mesh design is meant to hold grease "forever" per say...and not require re-lubrication. Well, I am going to say this - that is smoke and mirror talk. What you will see is eventually there will be many people having to replace their worn poly bushings on their RLCAs...and you will also see people having to completely tear apart their suspensions to remove the inner sleeve and re-grease to rid of squeaky noises.

Now to the main reason - performance. Bonded rubber vs free floating poly......in all honesty, the (guessing here, 70D ishhhhh) soft-ish poly is NOT going to perform all that much better than like a 57D stock rubber bonded bushing. It just isn't. Now, if both the fore and aft bushings were rubber and then you replace both with poly....there would be a pretty drastic difference in deflection.

So in a position like I am in, I have an extremely hard time suggesting an inferior product in this scenario. These are not a simple mod like a set of vertical links where you can experiment with 3 different styles in one day and 1 hour worth of work. This is a major modification and I truly believe that installing polyurethane bushings is just a poor decision. I can see the appeal when typing a reply on a forum....but in the real life, nah.

On that note, I am on my 5th S550 Mustang which I am very picky with. I installed the BMR-BK081 RLCA Spherical setup on the car with less than 100 miles on it. That and the FP Toe Bearing upgrade are 100% the very best first few mods for any performance enthusiast. You will find that even when I was with BMR I always stated how much of a fan of the RLCA bearing upgrade I was. As for NVH, I honestly never notice much of any increase in any of my cars. I think the majority of people who notice enough NVH to claim they regret it, have done something wrong somewhere with the installation.

Hope that helps explain.

 

[K4fxd]

Now, if both the fore and aft bushings were rubber and then you replace both with poly....there would be a pretty drastic difference in deflection.

Are you saying the poly is fine as long as you replace all the bushings in the rear control arm with poly?

 

[Jaymar]

Thank you @KellTrac, that is a lot of very good information to consider.

 

[Jaymar]

Are you saying the poly is fine as long as you replace all the bushings in the rear control arm with poly?

I think the rear pivot point on the rear, lower arm is already a bearing. That may only be the PP cars though.

 

[GT 550]

I realize these companies have these mesh interiors of their bushings as can be seen in earlier photos. That mesh design is meant to hold grease "forever" per say...and not require re-lubrication.

I may be missing something but the SuperPro bushing has a steel sleeve insert?

 

[Jaymar]

The mesh inside the sleeve (sometimes a groove) is meant to retain grease to avoid the squeaks and groans you usually get with poly bushings.

 

[SlowStangGT]

Have you tried putting the control arm in the oven for 15 minutes and the poly bush in the freezer? Usually helps a lot!

Shop canceled on me, but I Managed to get it on with the help of a friend aligning the bushing. We ended up tearing a camber arm bushing (100% our fault, not a problem with the bushing), so I had to purchase another one. RLCA went in straight though

Should be finished by Friday, and ready for an alignment next week. So stoked

 

[SlowStangGT]

Hi @Jaymar - thank you for the kind words.

Having been around this stuff and involved with developing products and catering to the end users for close to 20 years now, I can confidently express these opinions and as I stated, call a spade a spade. So that being said, let me explain my reasoning.

The stock bonded rubber bushing is not a great design for optimal performance. However, it DOES it's job. I should say, the "system" does it's job. Due to the rear bushing on the RLCA being a "spherical monoball" style, it does help the situation by only allowing the front pivot point to pivot and not push and totally distort.

When talking about replacing this specific part, we talk about a very involved job. So naturally I think it is best to suggest the best product for the work and cost involved.

When talking about poly vs Rubber. Meh. Sure, the poly design will have a "free floating" inner sleeve, but it is also off plane on rotation pivot so it will have a free moving range then it will stiffen as it pivots as it becomes unseated from its natural position.

When you cycle polyurethane like that it is very very very common to have what I call "cold flow" which is the material breaking down and deforming. This is very common with these sort of applications. NOW, that said, SuperPro has some excellent materials. Spades....their bushing designs and materials FAR EXCEED the quality of the Energy offerings from my very extensive experience with each company.

When we talk NVH. Poly is great....when it is great. lol. I realize these companies have these mesh interiors of their bushings as can be seen in earlier photos. That mesh design is meant to hold grease "forever" per say...and not require re-lubrication. Well, I am going to say this - that is smoke and mirror talk. What you will see is eventually there will be many people having to replace their worn poly bushings on their RLCAs...and you will also see people having to completely tear apart their suspensions to remove the inner sleeve and re-grease to rid of squeaky noises.

Now to the main reason - performance. Bonded rubber vs free floating poly......in all honesty, the (guessing here, 70D ishhhhh) soft-ish poly is NOT going to perform all that much better than like a 57D stock rubber bonded bushing. It just isn't. Now, if both the fore and aft bushings were rubber and then you replace both with poly....there would be a pretty drastic difference in deflection.

So in a position like I am in, I have an extremely hard time suggesting an inferior product in this scenario. These are not a simple mod like a set of vertical links where you can experiment with 3 different styles in one day and 1 hour worth of work. This is a major modification and I truly believe that installing polyurethane bushings is just a poor decision. I can see the appeal when typing a reply on a forum....but in the real life, nah.

On that note, I am on my 5th S550 Mustang which I am very picky with. I installed the BMR-BK081 RLCA Spherical setup on the car with less than 100 miles on it. That and the FP Toe Bearing upgrade are 100% the very best first few mods for any performance enthusiast. You will find that even when I was with BMR I always stated how much of a fan of the RLCA bearing upgrade I was. As for NVH, I honestly never notice much of any increase in any of my cars. I think the majority of people who notice enough NVH to claim they regret it, have done something wrong somewhere with the installation.

Hope that helps explain.

I definitely hear you out on this, however the reason why I am installing this is to
- A: Prioritize NVH reduction
- B: Reduce the rubber bushing binding
- C: Replace the rubber bushing with something that won't degrade as quickly over time

Point C is a huge reason why I was hesitant to go with the spherical bearing in the rear, given the various posts on RLCA bearing "clunking" noises growing over time. It's *much* more of a PITA to replace the RLCA bearing than the tension link up front; definitely makes me paranoid of them

I plan on using this as a daily driver with occasional HPDE use, and do not plan on doing *any* power mods. For wheel hop, the BMR CB005 should be all that I need, as most of my hard acceleration will be powering out of corners and not from hard launches. Whatever deflection that remains, I'm not convinced that it will be a problem for my particular use case

 

[KellTrac]

I think most issues with clicking is on the end user and the lack of proper installation/torque. Just my opinion. I have had 5 cars with them for a total of about 50K miles total driven on both the BMR BK055 and the BMR BK081 - not a single issue, ever.

I can say for certain that the BK055 has had a few "issues" One being that a few batches had issues with the center of the bearing spacers touching, and some of the bearings supplied by FK bearing were a little on the "too tight" side. But these are not major issues, very simple to resolve. Spacers too wide, grind them down a bit. Bearings too tight, silicone and drive the car.

 

[Radiation Joe]

I've replaced tension link bushings with bearings in the front on two cars previously and experienced zero NVH issues over 30k miles in one and 90k miles in the other. I've got to agree with Kelly on this one. If you are going through the effort of replacing bushings, you might as well put in bearings. If my BK055s get noisy in 30k miles I'll replace them with new Aurora bearings. It won't be that hard.
Regarding NVH in the rear: the sound from tire impacts is coming through more now than with rubber back there. It is not significant (at least for me), and the improvement in feel and large bump absorption is definitely worth it. Again, I'm glad I went with bearings instead of poly. Perhaps I will change my tune in 20k miles, but I doubt it.

 

[GT 550]

Again, I'm glad I went with bearings instead of poly

Just wondering if you've tried poly? If not it might be just as good or better for your intended purpose.

 

[Radiation Joe]

I've used poly many times in the past in different cars. It has its uses; just not this application, for the reasons stated in previous posts.

 

[TeeLew]

The mesh inside the sleeve (sometimes a groove) is meant to retain grease to avoid the squeaks and groans you usually get with poly bushings.

And it's better in some environments than other. I live in a dry part of the country, so it works well for me, because it never gets washed away. In particularly wet areas of the country, they will need to be pulled out and re-lubed every so often (yearly?)? Yes. At least for the time being, I can say that will be at something longer than 10k mile intervals. FWIW, I don't think Energy Suspension products are all that great, but they sell a good bushing grease for pennies.

 

[Jaymar]

And it's better in some environments than other. I live in a dry part of the country, so it works well for me, because it never gets washed away. In particularly wet areas of the country, they will need to be pulled out and re-lubed every so often (yearly?)? Yes. At least for the time being, I can say that will be at something longer than 10k mile intervals. FWIW, I don't think Energy Suspension products are all that great, but they sell a good bushing grease for pennies.

They do but the traditional smooth bushings generally end up washing out for me. I've never tried one of the cross-hatch style or grooved solutions so I can't speak to them. I used to just live with the creaks and groans but now I'm old and things like that make me cranky so these kind of questions come up when I'm making plans.

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