The term SR2 refers to a specific level of structural integrity or a reference standard used by bus body manufacturers. While not a universal ISO term, in the context of bus manufacturing (particularly in Asian and European body-on-chassis builders), SR stands for Structural Reference.
Thus, an SR2 ECE R66 bus skin is a structural outer panel (the "skin") engineered to participate in the load-bearing function of the bus during a rollover, meeting the specific energy absorption required for a standard two-axle passenger bus or coach. sr2 ece r66 bus skin
| Skin thickness (mm) | Max pillar intrusion (mm) – R66 | Max intrusion (mm) – SR2 | Mass change (%) |
|---------------------|--------------------------------|--------------------------|------------------|
| 0.7 | 155 (fail) | 212 (fail) | -8% |
| 0.9 | 112 (pass) | 138 (fail) | baseline |
| 1.1 | 89 (pass) | 96 (pass) | +12% |
| 0.9 + corrugation | 98 (pass) | 105 (pass) | +2% | The term SR2 refers to a specific level
Key finding: Corrugated 0.9 mm skin meets both R66 and SR2, with only 2% mass increase over flat 0.9 mm. Thus, an SR2 ECE R66 bus skin is
Even experienced bodybuilders make mistakes when chasing sr2 ece r66 bus skin compliance.
A high-quality, realistic skin for the SR2 ECE R66 bus focused on accurate livery, optimized textures, and compatibility with common simulator requirements.
Every bus compliant with ECE R66 (and specifically SR2 strength) will have a manufacturer’s plate stating "Regulation No. 66" and the specific variant (e.g., "R66/01" or "R66/02").