The Briton confirmed that cold tyres were implicated in his shunt at the Turn 1 left-hander at the Sebring International Raceway on the morning of the second day of the test aboard the #51 Ferrari 499P Le Mans Hypercar.
“I was coming out of Turn 1, I had the steering wheel almost straight and was short-shifting up to fourth so as not to get wheelspin, and then I hit that bump on the exit and lost it,” Calado told Autosport.
“That shows how easy it is to lose control on cold tyres now we aren’t allowed tyre heaters.
“There is the possibility of some big crashes this year because we are coming out of the pits on cold tyres.
“I’m just thinking about safety, not just for us professional drivers but also the amateur drivers on the grid.”
Calado stressed that the problem is only going to get worse when the WEC moves to Europe and the drivers face colder conditions than at Sebring.
“I know in the IMSA SportsCar Championship they have never used tyre warmers, but over here you are normally racing in temperatures above 20deg C,” he said.
“But can you imagine coming out of the pits at Spa [the venue for round three of the series at the end of April] and heading into Eau Rouge when it's 5deg C?”
“I dread to think what might happen; the speed differential into the corner between a car with a few hundred metres to warm up the tyres after coming out of the pits and a car at full speed is going to be enormous.”
The ban on pre-heating tyres has been introduced by the FIA on environmental grounds; tyres were previously placed in ovens powered by diesel heaters.
Calado suggested that it wasn’t necessary to go back to the such a set-up.
“We don’t need the tyres at full temp like in the past,” he explained.
“But we do need something that puts everyone’s safety in a better place.”
Calado described his impact with the wall at Turn 1 as “fairly low speed”.
“The problem was that I hit the wall at the wrong angle, and that caused the damage,” he said.
Ferrari has confirmed that the monocoque of the #51 has been replaced for the start of the Sebring 1000 Miles race meeting on Wednesday.
A spokesman said: “We undertook checks and preferred to change the chassis.”
Toyota driver Sebastien Buemi also raised the concerns about the differential in speeds as a result of the rule change.
“The worst thing is the difference in speed between someone on hot tyres and someone on cold tyres — I was overtaken by a GTE into Turn 1,” he said. “That is a bit dangerous.
“It is already hard here at Sebring, and it is pretty hot - so wait for Spa.
“Everyone will get better at it; I don’t know if it will reach an acceptable level, but right now it is very hard.”
Toyota Gazoo Racing Europe technical director Pascal Vasselon questioned whether it would be possible to reverse the ban on tyre warmers in the current political climate.
“Our view is that it is pain, but a necessary pain,” he explained.
“It is difficult to question the direction, but we know that the road will be bumpy.”
