Mercedes expects to risk new wheel rim design in finale

The Mercedes team is planning to run its controversial wheel rim design for this weekend's Abu Dhabi Grand Prix.

It will be the first time that Mercedes have run spacers featuring little holes that help cool the rear wheels since Japan.

Rivals had been rumoured to be planning an official protest against the team if it used the design in subsequent races, alleging that the holes amounted to movable aerodynamic features which are against the regulations. But the FIA ruled last month that the wheel rims were indeed completely legal.

Even so, Mercedes opted not to run the design in Mexico or Brazil while the driver and team championships were still undecided. Now that both have been successfully accomplished, the Silver Arrows look to be willing to take the risk for this weekend's season finale.

• FP2: Bottas puts Mercedes in charge in Abu Dhabi

“We wanted to avoid the controversy,” Mercedes boss Toto Wolff told Sky Sports F1. “It was a very hot topic. Ferrari didn’t like them, [even though] we got permission from the FIA to run them.

"We didn’t want the championship to end up in the courtroom. We didn’t see it is a massive benefit.

"[Now] the championship is decided so we can have a controversy after the last race. It doesn’t affect the championship any more.

“We are testing them today and then we will decide whether we run them open or closed,” he continued. “Probably we will run them open and see what the effect is."

Mercedes has also said it will not be fitting a new power unit into Lewis Hamilton's car, despite reliability scares in Brazil.

The team said at the time that Hamilton has been lucky to finish the race without suffering an engine failure. But they are now confident in using the same unit this weekend.

"The problem in Brazil was caused by a failure in the variable inlet system that caused unstable combustion," the team said in a statement.

"Engine settings were changed to contain the risk of failure and maximise performance during the race," it continued. "We have made hardware changes outside the sealed perimeter and we are running that engine (PU3) today.

"Data will be reviewed after FP2 to make sure all is okay," the team added.

A new power unit would push Hamilton over the allowed number for the season and see him take a grid penalty for Sunday's race.

Hamilton's team mate Valtteri Bottas - who was the fastest runner in Friday's free practice sessions at Abu Dhani - will also keep his existing power unit.

"We are both sticking with the old engines that we used in Brazil," the Finn confirmed. "At the moment everything looks fine, we should be able to do that, but we can confirm that during Friday."

Having older engines with many miles on the clock does carry the risk of a drop in power output for the race.

"We are quite confident," Bottas insisted. "It is not the same as having brand new engines, but I am sure we are not the only ones at the end of the year running quite old engines."

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