Quick answer. A jounce bumper — also called a suspension bump stop — limits suspension travel and absorbs impact energy at the end of the stroke. Miku Foam manufactures NDI microcellular polyurethane jounce bumpers with a progressive load curve, density grades from 0.35 to 0.65 g/cm3, validated to 500,000 fatigue cycles, and produced under IATF 16949 quality system (certificate # 0552607). What we make, the specifications that matter, and how to source for OEM-replacement, aftermarket, off-road, and heavy-duty applications.
What we manufacture
Miku Foam produces microcellular PU jounce bumpers for:
- OEM-replacement suspension bump stops
- Automotive aftermarket (AM) channel distribution
- Off-road and heavy-duty (modified trucks, Jeep / Bronco / 1500 / 2500HD, HD truck)
- Cold-weather and extreme-temperature service
- Private label / white label programs for distributors
Every part uses NDI (naphthalene diisocyanate) microcellular PU — the premium chemistry for jounce bumpers, chosen for its progressive load curve, fatigue resistance, and temperature stability. For the technical reasons NDI microcellular PU outperforms rubber, see our guide: Microcellular PU Jounce Bumpers vs Rubber Bump Stops.
Specifications
| Property | Range / Spec |
|---|---|
| Chemistry | NDI microcellular polyurethane |
| Density grades | 0.35 / 0.45 / 0.55 / 0.65 g/cm3 |
| Load curve | Non-linear, progressive |
| Fatigue life | 500,000 cycles validated (height loss 5.5%, ≤10% pass line) |
| Operating temperature | approx. -40 to +120 C continuous |
| Compression set | low, tested per ASTM D395 |
| Quality system | IATF 16949 certificate # 0552607 |
Full fatigue reports and static stiffness curves are documented on our Quality & Testing page.
Density grade selection
The right density depends on the application and load:
- 0.35–0.45 g/cm3 — lighter-duty and ride-comfort biased applications
- 0.45–0.55 g/cm3 — typical OEM-replacement range
- 0.55–0.65 g/cm3 — heavy-duty, HD truck, off-road, high-load
For replacement parts, match the original equipment density. For new designs, we work from the load requirement.
Sourcing: inventory, MOQ, and private label
- US west coast inventory hub — critical SKUs stocked in California for fast replenishment
- Private / white label — from 5,000 units per SKU, with IATF certificate traceability on the packaging insert
- Replenishment — roughly 4 weeks on stocked SKUs via the continuous-flow pipeline
Distributors evaluating a second source away from single-supplier dependence may find this guide useful: Why AM Distributors Are Diversifying from Single-Source Cellasto.
FAQ
Q: What is a jounce bumper? It is the suspension component that cushions the end of suspension travel, limiting metal-to-metal contact and absorbing impact energy. "Jounce bumper" and "bump stop" mean the same part.
Q: Why microcellular PU instead of rubber? Microcellular PU has a progressive load curve, far longer fatigue life, lighter weight, and wider temperature range. See the full comparison.
Q: What density should I order? Match the original equipment density for replacement parts, or specify by load for new designs. Grades run 0.35–0.65 g/cm3.
Q: Do you offer private label? Yes — from 5,000 units per SKU, with IATF 16949 certificate traceability on the packaging insert.
Q: Can I test before ordering volume? Yes. Sample units are available to order so you can run your own bench test. Contact our team to start.
Sourcing this line
Qualifying a supplier for this part? See how to vet a jounce bumper manufacturer for the NDI chemistry, fatigue-report, and IATF certificate checks to run before committing to volume.
Get specs, samples, or a quote
For density selection, test data, private-label setup, or pricing, contact our team. We respond with the technical detail your application needs.
*Miku Foam manufactures NDI microcellular PU jounce bumpers. IATF 16949 certificate # 0552607. Related: Quality & Testing · Microcellular PU vs Rubber · How to Vet a Manufacturer.*