British boys Adam Ellis and Zach Wajtknecht have agreed new deals with Swindon.
The reigning Premiership champions now have four of the side which won the title in October after unveiling Nick Morris and Tobiasz Musielak last week.
And boss Alun Rossiter said: “It’s good to have Adam and Zach back.
“Adam struggled at the early part of last season and there were people putting us under serious pressure to release him, but we stood by him.
“He ended up doing a fine job for the team and we’re delighted to have him back for next season.
“Zach is one of Britain’s best and most promising young riders and he is the kind of rider we want here at Swindon.
“We didn’t get to see the best of him last season because of the injury but we remain confident he will develop his career with us next season.”
Wajtknecht himself is thrilled to remain with the Robins for the defence of their title.
“I was over the moon when they asked me to go back to Swindon,” he said.
“I was just getting to grips with racing in the Premiership before I got injured.
“I was finding some consistency, my scores were improving and I was beating some good riders.
“So to be asked to go back gives me a chance to carry on from where I was really.
“The team is looking strong again with as many faces coming back from last season as we can and it would be amazing if we could win the league for a second season running in 2018.”