The Technology Behind DYNEST: A Spring, Cast Inside the Part That Already Fits
Every spring-loaded mechanism eventually runs into the same wall: a spring gives you range of motion but little control over the shape of its resistance, and an elastomer gives you a soft, forgiving touch but stiffens up in only one way — by getting harder as a material, not by changing how it's loaded. Engineers have lived with that trade-off for a long time. DYNEST removes it.
What DYNEST Is
DYNEST is elastomer-encapsulated spring technology — a compression spring cast fully inside solid polyurethane so the two behave as one part, not two components bolted together. It looks like an ordinary molded component. It doesn't behave like one.
Skateboard bushings are the first place you can feel it: see the current DYNEST bushings for HST, longboard, and street trucks.
How It Works
Picture a compression spring sitting inside a solid cylinder of urethane. As the assembly compresses, the spring compresses with it, and the gaps between its coils all shrink together — simultaneously, not one at a time. As those gaps close, they change how the surrounding polyurethane is loaded. Early in the compression, the material can move and flex the way an ordinary elastomer part would. Later in the compression, the closing coils progressively confine it, and it behaves like a much firmer material — even though nothing about the polyurethane itself has changed.
The result is a component that starts compliant and gets meaningfully firmer as load increases — producing more resistance than you'd get from simply adding a spring's stiffness to a block of urethane's stiffness. It's not a blend of two ingredients. It's a genuinely different structural behavior that only shows up when the two are combined this specific way, and it's what we've filed patent protection around.
Why It's Different: Three Variables Instead of One
A solid elastomer part is tuned by durometer alone. A coil spring is tuned by wire and geometry alone. Either one, on its own, offers a single lever to hit a target force curve — you approximate the shape you want and live with the compromise.
DYNEST is tuned across three variables that move independently:
- Matrix — the cast elastomer's chemistry and hardness set the baseline compliance and the shape of the early stroke.
- Spring — form and geometry set the rate and where the response starts to stiffen. Not limited to compression springs — the same principle applies in tension and torsion.
- Confinement geometry — how tightly the matrix is held against outward displacement as it compresses. This is the variable with no analogue in a conventional part, and it's the one that makes the curve genuinely progressive rather than just "softer" or "harder."
Because these three levers move independently, a DYNEST element can be tuned to match an existing part's design point while behaving differently on either side of it — more compliant approaching it, more supportive beyond it.
Beyond Skateboards
Skateboard bushings are where DYNEST started, but the underlying mechanism — a spring geometrically confined inside a cast elastomer — isn't specific to skateboarding. It applies anywhere a designer needs a progressive, space-efficient force response instead of a single fixed stiffness. A few directions we're exploring or fielding interest in:
- Medical devices — applications where a compact, tunable force profile matters more than raw stiffness, and where space for a mechanism is at a premium.
- Microelectronics — precision force delivery in a small footprint, where a conventional spring or elastomer alone can't hit the target curve inside the available envelope.
- Industrial equipment — vibration isolation and force-limiting components that need to behave differently at light load than at full load.
- Bicycles — suspension and damping elements facing the same soft-vs-stiff trade-off that motivated DYNEST in skateboarding.
- Aerospace hardware — weight-limited envelopes where getting more performance out of the same volume has real value.
None of these are shipping products yet — they're the kind of problems the underlying technology is suited to, and the kind of conversations we're having with engineers who bring us a specific application.
How Companies Work With Us
DJLL Holdings is a product development partner, not a high-volume manufacturer. If you're an engineer or product team with a load, displacement, and envelope problem, here's how an engagement typically goes:
- You bring the spec. Tell us the load range, the available displacement, and the physical envelope you're designing into.
- We design and prototype under NDA. Every engagement starts with confidentiality — your application, your numbers, your part stay yours.
- We characterize the result on calibrated instruments. You get real force-displacement data, not a simulation.
- Development is paid and non-exclusive by default. You own your application IP; we retain DYNEST and the improvements we make to it. Exclusivity is available at the tail end of a program, priced separately, scoped narrowly by category, territory, and duration.
- For production, we qualify manufacturing partners. We don't manufacture at scale ourselves where it isn't the right role for us — we own the specification, and certified partners produce against it, verified by first-article characterization. Qualification fee plus per-unit royalty.
Contact DJLL Holdings About Your Application
DYNEST™ and the pending patents covering this technology are owned by DJLL Holdings, LLC and licensed to Hamboards Holdings, LLC for skateboard applications. Patents pending: US 18/785,017; US Provisional 63/970,669.