Barnes, second overall and the best young rider in the BeNe Ladies Tour and bronze medalist in the U23 European road championships, comes across from the Drops Cycling Team to join her sister Hannah Barnes. Klein, 21, moves from Cervelo-Bigla, while neo-pro Riffel upgraded from trainee status.
"I am really excited to join the Canyon-SRAM line up," Barnes said. "This year I have had some great opportunities to ride for myself but I believe for me to move forward I have a lot more to learn. The staff and riders are very experienced and they can teach me a lot. I have always admired the way that they work as a unit and are always working towards one goal."
Barnes, 22, gained the attention of team manager Ronny Lauke thanks to some promising results in the Classics, such as a 7th place in Gent-Wevelgem and sixth overall in the Women's Tour in addition to her more recent success in the Netherlands.
"Alice raised our interest due to her fighting spirit and never give up attitude," Lauke said. "Her strength in classic races is very promising and her hunger for more is brilliant to see. Beating one of the icons in the sport, Marianne Vos, in a one-on-one sprint in Belgium recently was a very strong signal. We are pleased she has joined our setup for the coming year."
Barnes, Klein and Riffel each stated their intention of using the 2018 season to learn from the team's more experienced riders.
"Lisa is young, talented and already has achieved some promising results in classic events and races against the clock," Lauke said. "As well her personality will add quality to the team. She is not shy to address issues, always aiming for the highest possible, a true racer and a character.
"Alice and Lisa have each shown a willingness to work for their team's success, on and off the bike. But when an opportunity came up for their own glory, they have been both ready to take the chance. Heading into the same path, we see Christa and it's part of the reason we have extended her contract to the future.
"Christa has raced very promising during her stagiaire days," Lauke stated. "Always well positioned, always trying to protect teammates and fulfil the given job in the best possible way. It's made us confident we can work well with Christa and help develop her further."
The trio join Polish champion Kasia Niewiadoma as newcomers to the team, while the remainder of the renewals and other signings will be announced later this year.
"Overall we are very pleased and happy to have secured the trust of all four new signings," Lauke said. "We will help them further develop their career and aim to create some of the most talented athletes in the sport for the coming years."