Silicon Valley's LimeBike faces off against China's bike...

A race to dominate the rapidly growing smart bike market is on: Pioneering, unicorn-financed Chinese start-ups Ofo and Mobike are facing off in the United States with pumped-up Silicon Valley-based rival .

Freshly loaded with $50 million more in investment and geared up to launch in 10 more U.S. cities this year, LimeBike is pedaling fast in the United States to pass China's and with their big ambitions and billion-dollar coffers from China power players Tencent and Alibaba.

The United States is a new battleground for Ofo and Mobike, which invented and popularized the dockless bike-sharing market in China and have started to go international. Ofo kicked off operations in Seattle, Boston suburbs and Washington, D.C., in August, while Mobike launched in Washington, D.C., in September. Main U.S. competitor LimeBike kick-started its first U.S. market in June at the University of North Carolina at Greensboro and has quickly rolled out to 20 places.