Steel rings made of flat steel wires have been used in full steel loading meridian tyre without inner tyre before 10 years in advanced countries in Europe,such research in China is lacking.

• 欧洲发达国家10年前已将扁钢丝制成的钢丝圈用于全钢无内胎载重子午胎,我国这方面技术研究还不多。