Image 1 of 4 Kate Courtney (USA) wins the 2018 mountain bike world championships (Image credit: Rob Jones) Image 2 of 4 Kate Courtney (USA) (Image credit: Rob Jones) Image 3 of 4 Kate Courtney (USA) Specialized Racing (Image credit: Rob Jones) Image 4 of 4 Kate Courtney (USA) Specialized Racing (Image credit: Rob Jones)

World champion Kate Courtney has opted to leave the Specialized Racing Team, the bicycle manufacturer announced on Sunday, posting a farewell video on Youtube with the comment, "Time flies when you’re having fun and the last 5 years with Kate have been no exception. The last five years have been quite the journey, Kate. We look forward to seeing what the future has in store for you. Wear those Rainbow Stripes with pride."

Related Articles World champion Courtney signs with Scott-SRAM, focuses on Tokyo Olympics

Courtney posted a link to the video on social media, writing: "Celebrating an amazing partnership with @iamspecialized. Stay tuned for big news of where I’ll be going in 2019!"

Courtney ended a 17-year drought for the USA when she won the elite women's cross country title in Lenzerheide, Switzerland in September, dropping 2016 champion Annika Langvad on the final lap.

The American's result was the country's first world title in cross country since Alison Dunlap's emotional victory following the September 11 terrorist attacks in 2001.

Courtney has enjoyed a meteoric rise since graduating from Stanford University, winning the Cape Epic with Langvad in March, and a second US national championship title in July.

In 2017, Courtney won the silver medal in the U23 category at MTB Worlds behind Swiss rider Sina Frei after dominating in the U23 World Cup, taking four of the six races.