Updated UCI equipment regulations for 2019 now render the Castelli Body Paint 4.0 speed suit non-compliant. The speed suit featured 'vortex dimples' on the sleeves and was controversially used by Team Sky during the 2017 Tour de France opening stage.
The updated rules also affect Endura's Drag2Zero speed suit as used by Movistar Team, that also features a textured material on the sleeves to improve aerodynamics in time trials.
Bioracer's speed suits, which recently dominated at the world championship time trials, feature ribbed sleeves aiming for the same aerodynamic effects as Castelli and Endura's offerings. However, Bioracer say they were involved in the meetings with the UCI leading to the regulations and their ribbed material does not fall under the ruling as it is below 1mm.
The full update to the UCI rule, in the chapter for Equipment - Section 3: riders' clothing states: "Items of clothing may not modify the morphology of the rider and any non-essential element or device, of which the purpose is not exclusively that of clothing or protection, is forbidden.
"Modifications to the surface roughness of clothing are authorised but may only be the result of threading, weaving or assembling of the fabric. Surface roughness modifications shall be limited to a profile difference of 1mm at most.
"The measure of surface roughness modification shall be made without pressure or traction on the clothing.
"All clothing must maintain the original texture of the textile and may not be adapted in a manner to integrate form constraints. Therefore, when not worn, clothing may in no case contain any self-supporting element or rigid parts"
In an email to Cyclingnews, Castelli Brand Manager Steve Smith confirmed the vortex speed suit would now be non-compliant: "Both the Castelli 4.0 'pimple' suit and the Endura [Drag2Zero] suit become illegal. And the grooves in all those suits with the grooved fabric should also be illegal since it's more than 1mm," he said.
"We've been working on a number of new speed suits that comply fully with the new regulations and are in fact faster than the 4.0 pimples suit. So, we're actually quite happy."