The American former world champion, Katie Uhlaender, claims rivals have raised questions after some blistering training runs, with the matter discussed in today’s team captains’ meeting.
And she claims it’s not the first time Team GB’s appliance of science has divided the sport.
Despite coming in ranked seventh and ninth in the world, Laura Deas posted the fastest time in training – an unofficial track record – with Yarnold second quickest.
In six runs down the track, the British pair were consistently ranked in the top three, with a Team GB slider in the top position on three occasions.
“A lot of athletes and coaches have questioned about whether the suit are legal,” said Uhlaender, who finished fourth behind Yarnold in Sochi four years ago.
“I think this has been a question posed of Great Britain in the last two Winter Olympics, starting in 2010 with Amy Williams and her helmet and suit.
“The rules state that everyone is supposed to have access to the same equipment as far as helmets and speed suits go and not have any aerodynamic attachments on the helmet or suit.
“I think it’s right to ask the question and make sure everyone is on a fair playing field.
“I was trying to get a suit of the same quality and I was told it was illegal. This is like Amy’s helmet in 2010 and, in my opinion, that helmet was illegal.”
It’s not the first time Britain and the USA have clashed over technology in the sport.
Williams was allowed to keep her gold medal after protests from nations, led by the US. And, four years ago, American slider Noelle Pikus-Pace was tearfully disqualified from a World Cup race after the British team saw three bits of tape of her handle, the decision promoting Yarnold to gold.
British officials have been working with scientists and the English Institute of Sport to create a race suit that reduces wind resistance and turbulence, shaving vital fractions as athletes reach speeds of the 90mph.
But, unlike cycling, it’s sport that’s open to the elements, leading others to question just how great the advantage is.
Yarnold – who is attempting to become the first British athlete to win back-to-back Olympic medals – brushed off concerns with Team GB lawyers confident there is no case to answer
A Team GB spokesperson said: “We are confident that all competition equipment meets the technical and commercial requirements for every sport and discipline.
“We do not comment on specific technical aspects of equipment prior to competition.”
Watch Lizzy Yarnold and Laura Deas go for gold on Eurosport 1 at 11.20am today. Don’t miss a moment of the Olympic Winter Games on Eurosport and Eurosport Player. Go to www.eurosport.co.uk