Rapha, the upmarket and trendy British bikewear brand, has been sold to two grandsons of Sam Walton, founder of Wal-Mart Stores.

Rapha, founded by branding consultant and lifelong cyclist Simon Mottram in 2004, has been sold to RZC Investments, a private equity firm run by Steuart and Tom Walton, who are reported to be committed mountain bikers. The firm also has an investment in bike maker Allied Cycle Works, based in Little Rock, Ark.

Since it launched, Rapha has been owned by Mottram and a group of founder shareholders. In…