Alpinestars Nucleon KR-Ci Chest Protector

Alpinestars Nucleon KR-Ci Chest Protector — Sternum Coverage Done Right

Most jackets ship with no chest protection at all. The KR-Ci fixes that — it's a standalone chest insert that fits the chest pocket of compatible Alpinestars jackets and many universal jacket chest pockets.

Materials & Vegan Verification

Alpinestars Nucleon foam: a closed-cell polyurethane elastomer. Verified vegan. No leather, no animal-derived adhesives, no wool components. The harness webbing is fully synthetic nylon.

Protection

• CE Level 1 (EN 1621-3:2013) — chest protectors
• Nucleon multi-density foam: soft outer shell absorbs low-speed contact, dense inner core disperses high-energy impact
• Anatomical pre-curve for sternum and rib coverage
• Air channels for ventilation during long rides
• Compatible with Alpinestars CE chest pocket jackets and many third-party jacket chest pockets

Why Chest Protection Matters

EN 1621-3 (chest) is distinct from EN 1621-2 (back). Level 1 transmits a mean force below 18 kN across the sternum and ribs. Without a chest protector, all impact energy transfers directly to the sternum — a bone that cannot be casted. Most riders skip this. Most accidents involve front-impact contact.

Fit & Sizing

Two sizes available: standard and large. The KR-Ci uses a universal harness-pocket profile. Check your jacket's chest pocket dimensions before ordering.

Verdict

If your jacket has a chest pocket and it's empty, this is a €40–50 upgrade that adds meaningful certified protection. It's thin, light, and disappears under the jacket. There is no reason to skip it.

Verify current EN 1621-3:2013 Level 1 certification at point of purchase.