The (new) UCI rules on go-faster clothing are (sort of) clear: "it is forbidden to wear items designed to influence the performances of a rider such as reducing air resistance or modifying the body of the rider (compression, stretching, support)."
Such rules are open to interpretation which is likely the argument Team Sky used with the UCI to justify the use of what look to aero expects like aero arm wires on the time trial suit used by Bradley Wiggins on stage nine of this year's Tour de France.
The skin suit has the logo of the Tour's clothing supplier - Le Coq Sportif - but it's believed the suit was probably made by Moa Sports of Italy.
Head-on photos of Bradley Wiggins on stage nine (slightly more hi-res version) clearly show his suit has linear features on the arms. These lines could be the sort of 'wires' which are thought to trip air flow, delaying separation of the boundary layer, which reduces drag.
Such wires, in a strict reading of the UCI's rules, are not allowed. The UCI has said Sky cleared use of the suit before the Tour de France.
Chris Boardman, tech liason for British Cycling - connected to Team Sky - is said to have had all of British Cycling's go faster gear checked and cleared by the UCI. In theory, this Team Sky TT suit could be similar to the TT suit Wiggins will use in the Olympics 2012 time trial.
In 2010, Pearl Izumi made 'Speed Shop' aero suits for the Garmin-Cervélo team. The 'wired wings' on these suits were found to breach the UCI rules and were banned.
James Lamont, the clothing consultant who worked on the original adidas time trial suit, adapted by Team Sky (produced for adidas by Moa Sports), told BikeBiz:
"The original suit I built is all about clever seams, clever placement, clever cutting of fabrics, clever fabric selection. We did loads and loads of wind tunnel testing, CFD, of seams, fabrics, shapes, angles and orientations, and then tested loads of suits in wind tunnels.
"I rolled together work for summer and winter Olympics (Luge, Skeleton, Bob, Speed Skating), which let me justify the investment."
Lamont - a Scot based in Italy - believes Team Sky may have placed the 'wires' beneath his original suit.
UCI's technical coordinator Julien Carron said the 'wires' were, in fact, seams and the time trial suit is UCI compliant:
"We already checked the Team Sky clothing equipment at the UCI a few months ago and we approved it. Those are just seams placed in a maybe unusual and visible position. There is no support or compression effect and we have no evidence that this placement of seams gives more aerodynamic advantage than anywhere else and even if it does, there is no precise definition of the dimensions, positions and kind of seams allowed in the clarification guide. This skinsuit is in conformity with the current UCI regulations.
"To be absolutely sure everything is ok, we already asked Team Sky to provide us with the same suit that was used by Wiggins during the Tour de France to check that nothing changed after our validation."