Update 02/20 Lego part #98613


Update 02/20/2019 It turns out the rubber like part in the center is made out of TPU or thermoplastic polyurethane but I am not quite sure how long the lifespan is for this material as I could not find the information anywhere online if anyone knows PLEASE say so in the comments. I am really wondering what this part is made of especially the center which is a different material entirely, it’s a black center with a softer feel and material. I am wondering if it is rubber? If so then there is the concern of deterioration and cracking down the road, and due to me using this part in so many mocs, it is important for me to find out this information. Let me know if anyone knows. Thank you.

The interior is black, yet the rubber is transparent if you insepct closely.

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So is it rubber or a soft plastic? Rubber will only last about 10 or more years before it starts to break down.

I don’t have any of these parts but if I had to guess it’s probably just a small rubber cushion intended to cause friction in the joint. I wouldn’t worry too overly much about them because parts like these don’t tend to degrade too much over the years.

I have stuff from 2001 that may as well be brand new, and if those pieces are fine 20 years later, given the better materials Lego uses nowadays, you should be perfectly fine!

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Awesome! Yeah the center is only slightly softer, it feels more like plastic but softer, perhaps it is actually a soft plastic and not rubber, usually rubber is softer than what’s in this part.

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Its definetly some sort of rubber.

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That is unfortunate. But who knows, maybe it will defy usual rubber lifespan and last past 10 to 20 years.

It already has for most of mine.

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Well that’s great, yeah actually the only parts I have that show any sign of aging was a new maxilos and spinax I opened up and the spines and tubes were sticky. I read somewhere today that Lego uses SBS polymer for it’s tires and elastic materials. Which I found can last upwards of 40 years kept in the right conditions. But I’m not sure how accurate the info is, it stated it was said by a Lego representative.

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That is some kind of rubber I think. It is making the joints move a little harder.

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As far as I’m aware, it’s made of Styrene-Butadiene Styrene (SBS). [source]

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So I actually contacted Lego just to see what they would say and the representative replied with this: “While the majority of LEGO bricks are made of ABS (acrylonitrile butadiene styrene), this one seems to be made of HV-PC, a type of polycarbonate.” But I believe this answer is talking about the part itself not the inner flexible part. But yeah it probably is SBS, if that’s what they use for every other flexible part.

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I believe so too, it does appear different from the ABS. Polycarbonate is what is used for transparent pieces, which makes them more durable as opposed to had they been molded transparent in ABS. Makes sense considering that it would need to withstand more pressure.

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Aha! So I found out from the same Lego Representative after he did some investigating. “Looks like that part 98613 is a singular component that is not found by itself and will always have a black rubber insert. Together, they both make up element 74261 which is a combination of both pieces. That is how it would be found in sets. The outer shell is made of HV-PC and the inside ball joint is made of TPU, or thermoplastic polyurethane. It is not rubber, but a different type of plastic.” So the black part is made of TPU but I’m not sure how long it lasts, I can’t find any information on longevity online.

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Interesting. I haven’t heard of that material before.

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What is strange is that I cannot find any information on the lifespan of TPU. Nothing.

I wouldn’t worry about it too much, honestly. Plastics in general have a lifespan of “After you.” Unless you’re putting them through pretty heavy use and impacts there should be no breakage, and if that part is anything like the rest of the Bionicle Pieces I know, that rubber is there to stop general wear on the piece more than it is to stop it going completely limp. The majority of friction on the piece should be coming from the “clips” that hold a ball joint.

Thermoplastic Polyurethane should have a similar lifespan to regular Poly, with the difference being as long as you don’t subject it to extreme heat. Best I can find is you’re looking at 10-15 years, same as most other stuff. Though that’s for general applications. I imagine molded pieces will be longer lasting.

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I see, I did just find that PU or polyurethane can last upwards of 50 years if kept right. But not sure if that longevity applies to thermoplastic polyurethane.

The only difference between “normal” poly and thermoplastic is that thermoplastic is designed to melt if heated past a certain temperature. If anything, it should last longer as long as the molding process didn’t leave any internal flaws.

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Yeah you’re right, I just found this “The life expectancy of thermoplastics in durable applications varies from about 10 years to 50 and even 100 years in certain cases.” It also stated upwards of 50 years for polyurethane on the same sight.