Welcome to ROSDBBMX

Updated 20th March 2026

Welcome to ROSDBBMX: The Archive (1977–1984)

Your definitive resource for Real Old School Diamond Back BMX history, frame identification, and technical research.

If you are looking for evidence-based data on the "Black and Silver" era of the Western States Imports (WSI) Diamond Back BMX brand, you are in the right place. This archive is built on 20 years of hands-on restoration, the cataloging of thousands of serial numbers, and the study of original factory material and direct contact with those that were part of it.

Quick Tools & Research

Identify Your Frame: Interactive Serial Number Decoder – Use our tool and geometry table to verify your Diamond Back frame.

Technical History & Lore – Explore original research on the "VM" prefix, manufacturing shifts, and the 1979–1984 production window.

[Factory Archive Gallery - coming soon] – View high-resolution scans of original pricing catalogs, flyers, and brochures (under construction)

Why ROSDBBMX is a Primary Source

Much of the information presented here is the result of direct investigation into surviving bikes and components, supported by:

Direct Industry Contact: Insights gained from discussions with former employees of both WSI and Diamond Back, as well as the inner circle of the legendary Cozy Yamakoshi.

Original Documentation: A personal archive of factory-original catalogs and period materials dating back to 1979.

Authenticity Verification: Detailed study of frame geometry transitions, including the evolution of 2mm vs 3mm dropouts and seat tube angles.

While I can offer general advice on models beyond 1984, this site remains a specialized deep-dive into the "Diamond Gusset Era" (1977–1984). If you are searching for original source information rather than recycled internet rumours, feel free to get in touch.

Community & Connections

I am no longer actively involved in the broader online BMX scene, but for those seeking a community of genuine enthusiasts, I personally recommend:

Old School Diamond Back BMX Official (Facebook Group)

BMXmuseum.com (Member since 2009)