Metalcloak Kevlar Duroflex Joints

Adding Kevlar to our proprietary rubber compound that makes the Duroflex joint so effective is just a bet that they will do even better, and since the cost to our customers doesn't change, it is a bet that we are willing to take.

Just to clarify, it's possible that the Kevlar could also not improve your product? Did you take a bet or research?

Speaking of research and reproducable results, have you had time over the last year to get that fancy fender clearance chart made up?
 
So...Since there isn't anything really useful being offered in this thread, I'll add why fiber fillers are added to thermoplastics. Typically, its for strength purposes. For instance, on an outside rearview mirror on your car or truck, the mounting bracket used to be made from Aluminum or magnesium (some still are). However, plastic parts are generally less expensive to produce, so the mounting brackets have been moving toward that material. On a small car mirror, that is great. On a large truck mirror (think F150) the plastic isn't stiff or strong enough to pass government testing. The image is blurry (there is a spec in the FMVSS for image stability) and they may fall off the vehicle upon impact or in a car wash (which will be a customer issue...Think hitting your garage door while pulling in kind of impact). So, the resin suppliers put their thinking caps on, and load up the mixture with tiny glass fibers. Or Aramid, or Carbon, etc. Glass is most common, because its least expensive. The highest glass concentration I've ever seen used is a 60% glass filled plastic on a Toyota Mirror. For some engineering stuff...

A generic, picked at random Polypropylene has a tensile strength of 4200 psi. The material is RheTech Polypropylene CC20P100-00. Its a calcium carbonate filled material...the Calcium is added to help control sink (polypropylene has a coefficient of expansion so they add stuff to help control that property). If you take the same material (RheTech Polypropylene G10P100-00), and add just 10% glass fiber to it, the Tensile strength increases to 7100 psi. Stiffness and hardness also increase.

Interesting to note...A polypro material with aramid fibers (RTP 100 AR 15)... Tensile strength is 5200 psi, but the impact resistance is higher (so its "tougher" i.e. less brittle).

Now...this data is applicable to thermoplastics, you can see all the specs at www.ulprospector.com and register for an account...I don't know much about the molding of rubber...Its possible that the kevlar was added to add some resistance to tearing (as @bobthetj03 has experienced) but it seems that that resistance may come at a cost of some flexibility...which opens the debate to usable vs total flex again. Again...I'm applying knowledge of thermoplastics to a thermoset material (rubber) so whether the additive reacts the same...I cannot say for sure.

The more you know...
 
I've accepted a challenge from @Matsonian . He is going to send me a set of lower bushings with the new magical formula to replace my current bushings. My lowers have over 30K miles on them, so it will be interesting to see how they are wearing. I'll post my findings on this thread when it all goes down.
 
Thanks for your input on this @Ranger_b0b . Having been in the collision industry and automotive refinish industry, I actually can understand a little of what you posted.
 
If Savvy were to announce tomorrow that they have improved the JJ's to be more durable(not sure how that can even be possible), wouldn't you question your purchase as not being the best quality you could buy?

I'd be satisfied that I've purchase a quality product that will serve me well and at the same time be glad to hear that the product has been improved.

I've accepted a challenge from @Matsonian . He is going to send me a set of lower bushings with the new magical formula to replace my current bushings. My lowers have over 30K miles on them, so it will be interesting to see how they are wearing. I'll post my findings on this thread when it all goes down.

nice
 
My fellow wheelin buddy, @b0xcar, has the MetalCloak 3.5” Suspension System complete with arms. It’s very capable. Not sure how many miles he has on it, maybe 3-4,000? In any case, for what it’s worth, the system seems really solid.
 
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My fellow wheelin buddy, @b0xcar, has the MetalCloak 3.5” Suspension System complete with arms. It’s very capable. Not sure how many miles he has on it, maybe 3-4,000? In any case, for what it’s worth, the system seems really solid.
It has been great to me so far. I have around 4000 miles on it. I will take a look at them after a year and see how they look.
 
Would the addition of Kevlar allow the Duroflex bushing to be used in the frame side of the MC track bar?
Part of our testing was whether we could add Kevlar without changing the durometer of the rubber — changing the durometer would, of course, change the overall performance —- because we did not increase the durometer of the rubber the vibration dampening and isolation qualities of the Duroflex joints remains intact —- the opposite of what you want on a track bar.
 
So...Since there isn't anything really useful being offered in this thread, I'll add why fiber fillers are added to thermoplastics. Typically, its for strength purposes. For instance, on an outside rearview mirror on your car or truck, the mounting bracket used to be made from Aluminum or magnesium (some still are). However, plastic parts are generally less expensive to produce, so the mounting brackets have been moving toward that material. On a small car mirror, that is great. On a large truck mirror (think F150) the plastic isn't stiff or strong enough to pass government testing. The image is blurry (there is a spec in the FMVSS for image stability) and they may fall off the vehicle upon impact or in a car wash (which will be a customer issue...Think hitting your garage door while pulling in kind of impact). So, the resin suppliers put their thinking caps on, and load up the mixture with tiny glass fibers. Or Aramid, or Carbon, etc. Glass is most common, because its least expensive. The highest glass concentration I've ever seen used is a 60% glass filled plastic on a Toyota Mirror. For some engineering stuff...

A generic, picked at random Polypropylene has a tensile strength of 4200 psi. The material is RheTech Polypropylene CC20P100-00. Its a calcium carbonate filled material...the Calcium is added to help control sink (polypropylene has a coefficient of expansion so they add stuff to help control that property). If you take the same material (RheTech Polypropylene G10P100-00), and add just 10% glass fiber to it, the Tensile strength increases to 7100 psi. Stiffness and hardness also increase.

Interesting to note...A polypro material with aramid fibers (RTP 100 AR 15)... Tensile strength is 5200 psi, but the impact resistance is higher (so its "tougher" i.e. less brittle).

Now...this data is applicable to thermoplastics, you can see all the specs at www.ulprospector.com and register for an account...I don't know much about the molding of rubber...Its possible that the kevlar was added to add some resistance to tearing (as @bobthetj03 has experienced) but it seems that that resistance may come at a cost of some flexibility...which opens the debate to usable vs total flex again. Again...I'm applying knowledge of thermoplastics to a thermoset material (rubber) so whether the additive

I wasn’t trying to be critical, I just don’t see any practical reason for the addition of Kevlar
So...Since there isn't anything really useful being offered in this thread, I'll add why fiber fillers are added to thermoplastics. Typically, its for strength purposes. For instance, on an outside rearview mirror on your car or truck, the mounting bracket used to be made from Aluminum or magnesium (some still are). However, plastic parts are generally less expensive to produce, so the mounting brackets have been moving toward that material. On a small car mirror, that is great. On a large truck mirror (think F150) the plastic isn't stiff or strong enough to pass government testing. The image is blurry (there is a spec in the FMVSS for image stability) and they may fall off the vehicle upon impact or in a car wash (which will be a customer issue...Think hitting your garage door while pulling in kind of impact). So, the resin suppliers put their thinking caps on, and load up the mixture with tiny glass fibers. Or Aramid, or Carbon, etc. Glass is most common, because its least expensive. The highest glass concentration I've ever seen used is a 60% glass filled plastic on a Toyota Mirror. For some engineering stuff...

A generic, picked at random Polypropylene has a tensile strength of 4200 psi. The material is RheTech Polypropylene CC20P100-00. Its a calcium carbonate filled material...the Calcium is added to help control sink (polypropylene has a coefficient of expansion so they add stuff to help control that property). If you take the same material (RheTech Polypropylene G10P100-00), and add just 10% glass fiber to it, the Tensile strength increases to 7100 psi. Stiffness and hardness also increase.

Interesting to note...A polypro material with aramid fibers (RTP 100 AR 15)... Tensile strength is 5200 psi, but the impact resistance is higher (so its "tougher" i.e. less brittle).

Now...this data is applicable to thermoplastics, you can see all the specs at www.ulprospector.com and register for an account...I don't know much about the molding of rubber...Its possible that the kevlar was added to add some resistance to tearing (as @bobthetj03 has experienced) but it seems that that resistance may come at a cost of some flexibility...which opens the debate to usable vs total flex again. Again...I'm applying knowledge of thermoplastics to a thermoset material (rubber) so whether the additive reacts the same...I cannot say for sure.

The more you know...


I wasn’t trying to be critical, I just don’t see how adding Kevlar would benefit the product.

Yes Kevlar has high tensile strength but poor abrasion resistance.

I also understand why fibers are added to plastics or concrete but adding a fiber that does not resist abrasion well does not really add anything in a torsion application, does it?
 
Part of our testing was whether we could add Kevlar without changing the durometer of the rubber — changing the durometer would, of course, change the overall performance —- because we did not increase the durometer of the rubber the vibration dampening and isolation qualities of the Duroflex joints remains intact —- the opposite of what you want on a track bar.

Hopefully your engineers (or your supplier's engineers) know that durometer is not everything in using a reinforced elastomer as a vibration isolator. The change in young's modulus and the bulk modulus will have an effect on the dampening.

I'm curious what the goal of adding the Kevlar was - what problem is it addressing or improvement is the new material offering? Or was it simply a "why not - it's got to be better - right?" type thought?

Don't get me wrong - it's very possible the kevlar will improve the strength and durability of the joints while having a minimal effect on the vibration isolation. But without test data, I would be very hesitant to make that claim.
 
Hopefully your engineers (or your supplier's engineers) know that durometer is not everything in using a reinforced elastomer as a vibration isolator. The change in young's modulus and the bulk modulus will have an effect on the dampening.

I'm curious what the goal of adding the Kevlar was - what problem is it addressing or improvement is the new material offering? Or was it simply a "why not - it's got to be better - right?" type thought?

Don't get me wrong - it's very possible the kevlar will improve the strength and durability of the joints while having a minimal effect on the vibration isolation. But without test data, I would be very hesitant to make that claim.

Very well stated. And yes, the inventor of the Duroflex joint is very aware of what makes the rubber joint so effective. However, I am not an engineer and try not to pretend to be one on the internet.

I can say, however, that the 18 months or so that transpired from the idea of a Duroflex Gen2 and pulling the trigger on production were all about determining the overall value of making a change. We could either go down the path of "it ain't broke so why fix it" or, as previously stated, determine that this new proprietary rubber compound will do even better then the original — all testing that was completed (the same testing conducted prior to releasing the original Duroflex Joint in 2011) showed us even better results.
 
@Matsonian , when did the new improved Duroflex joints start shipping? I had your GC 3.5 installed by a shop here in Atlanta back in March timeframe. Would that be Gen1 or 2 Duroflex?
 
@Matsonian , when did the new improved Duroflex joints start shipping? I had your GC 3.5 installed by a shop here in Atlanta back in March timeframe. Would that be Gen1 or 2 Duroflex?

They started quietly being introduced in March, as inventory permitted. Kits that shipped in that time frame were only partially Kevlar.
 
Well my pretties, @Matsonian isn't messing around here! Got these just a while ago.
20180629_122322.jpg
 
Now to find time somewhere between the honey do list to swap out these bushings. It will be interesting to see how the gen 1 bushings are holding up after 30K miles.
 
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Now to find time somewhere between the honey do list to swap out these bushings. It will be interesting to see how the gen 1 bushings are holding up after 30K miles.

Let me know how difficult your original ones are to remove. When we were swapping shocks to the Rocksports we took off the rear controls arms that had developed a creak. It was a real pain in the ass to remove the bushings, but we got them out, cleaned everything up, relubed, and put back together and they were quiet again.

I actually have it on my to do list this weekend to inspect all of the bushings.
 
Let me know how difficult your original ones are to remove. When we were swapping shocks to the Rocksports we took off the rear controls arms that had developed a creak. It was a real pain in the ass to remove the bushings, but we got them out, cleaned everything up, relubed, and put back together and they were quiet again.

I actually have it on my to do list this weekend to inspect all of the bushings.

Yep, I'll post pics of the removal/install process. I have never serviced or lubed the originals, so it should be interesting to see how difficult they will be.