Red Bull's Christian Horner is pushing back on claims by Renault that the Milton Keynes-based outfit must decide its 2019 engine plans by May.
Red Bull's engine supply contract with the French manufacturer runs out at the end of the current season. The team's relationship with Renault suffered some tensions at the end of last season following a series of setbacks suffered by its junior squad Toro Rosso.
The Faenza-based team has switched to Honda this year, and Red Bull will be attentive to the Japanese manufacturer's performance as it envisages its own change of partnership for next season.
Renault Sport F1 boss Cyril Abiteboul recently said Red Bull will have to decide between Renault and Honda for 2019 by May of this year. But Horner says that deadline is wrong.
"What we understand is that May is when you have to give an indication to the FIA, but that does not mean a commitment," Horner told El Confidencial.
"It will be decided at the end of the summer. That's the realistic timing of when the decisions have to be made."
So far, Honda may actually hold an advantage after a surprisingly strong and reliable pre-season test for Rosso.
"Honda has had a fantastic start with Toro Rosso," agreed Horner.
"Obviously, we're in a good position to keep an eye on their progress in the first half of the year. We're going to follow it with great interest," he added.