Most of the World Endurance Championship rules that govern crazy Le Mans prototypes like Toyota's and Nissan's remain unchanged from 2014, yet a regulations clarification is the biggest news of the offseason. It appears as though someone (perhaps ) had body parts that flattened down at speed.

Although the big technical controversy last year was the flexible rear engine cover trailing edge on the Porsche 919 that was discovered during Le Mans testing, it was Toyota who apparently continued to fly under the radar with a rear end made to flatten down for less drag at speed. Porsche's rear bodywork was flexible to the point where they replaced it with a more rigid piece for the race, but the damage was done: all eyes were on the 919, and none on Toyota's TS040.

Mulsanne's Corner first pointed out the suspicious wing back in , complete with of how the entire assembly works. Essentially, the entire wing assembly rotates past a certain speed, reducing drag on long straights. (A more technical description of how it works can be found .)

The wing assembly was rigid enough to escape ire from the scrutineers, but definitely came alive when the car reached a certain speed. However, it seems as though the FIA caught on for 2015.

According to , the FIA released a regulations clarification that specifically bans the kind of flexible body work the TS040 was sporting.

"The rear wing must be rigidly (rigidly secured means not having any degree of freedom) attached to the chassis or to the transmission casing or to the rear absorbing structure of the car," states the revised Article 3.2.6 c/ of the WEC regulations. Rear wind endplates now must be attached to the car's bodywork, and more stringent load tests are being performed to ensure that none of the bodywork they're attached to will move under aerodynamic load.

Everyone loves a good, clever hack around the current stated rules. Toyota designed a system that appears to have passed all the required tests for 2014, but clearly went against (or "around," should any Toyota fans be in the room) the spirit of the rules.

Sorry, Toyota. You'll have to come up with something new for 2015.