求翻译：关于电机车轮径，可以做到750mm，但是交货周期长、价格贵、国内没有这个规格需定做，建议使用国内规格，厂家已有的轮径尺寸是什么意思？

On the motor wheel diameter, 750mm can be done, but long, expensive, domestic delivery period without the specifications you want customized, suggested using national specifications, manufacturers have some wheel diameter