Acer air springs item NO. 2B-220-180(8112220180) are being tested by National Bus Quality Supervisory Center according to GB/T.13061-91 standard of "air spring for auto suspension system" on August 8th 2007. The test including expansion and contraction test, air sealing test, spring characteristic test, and fatigue test.
Testing result meet all the requirements of "air spring for auto suspension" GB/T.13061-91. It is still in good condition after 3080 thousand operation with frequency of 3 Hz and range of ±29mm.