Mercedes face upgrades u-turn after 'introducing problems'

Mercedes is planning a reintroduction of the upgrades it presented at the start of the Belgian Grand Prix before a dramatic swap led to its victory at the Spa-Francorchamps circuit.

Since discovering the correct development path this season under the current aerodynamic regulations, Mercedes has rapidly developed the W15s to such an extent it has won three of the last four grands prix, two of which have been on merit.

In Belgium, however, after adding further updates to the cars, a win did not seem possible following Friday's two practice sessions when Lewis Hamilton and George Russell were off the pace.

The team opted to revert to the Silverstone package that brought Hamilton an emotional victory as he ended a staggering 56-race winless drought, and it again reaped dividends.

Although Russell took the chequered flag, he was later disqualified due to being underweight, allowing Hamilton to inherit the 105th success of his F1 career.

As to the route Mercedes will now take for the next race after the summer break, the Dutch Grand Prix at Zandvoort, trackside engineering director Andrew Shovlin said the team is "planning" to reinstall the Spa upgrade package.

"The reason we reverted the car to the Silverstone spec on Friday night was because we had a good race in Silverstone," said Shovlin.

"Spa and Silverstone are not dramatically different circuits in terms of the corner speed range that you are dealing with. We had clearly introduced some problems somewhere.

"We think that was largely due to how we were running the car in Spa, not induced by the updates themselves. That was giving us a bit of bouncing in the high-speed corners, as well as a few issues with the balance. Going to that Silverstone car got it all back to normal.

"We have since had time to look at the data to understand what it was that we did, and we are pretty confident that we will be going for a reintroduction in Zandvoort."

Mercedes was faced with 'large number' at Spa

Explaining the turnaround in spec, Shovlin has confirmed the new package had resulted in old issues resurfacing.

"One of the issues with Spa is it is a fast circuit, and it needs a lot of commitment from the driver," he said. "We managed to introduce a bit of bouncing to the car, so in the high-speed corners that is not great for their confidence.

"There were a couple of other balance issues where they had a lack of entry stability. When you want to brake late and carry speed into a corner, that does not help.

"At a normal track, that might have cost us a little bit of time. On a big circuit like Spa with some pretty big corners, that was becoming a large number.

"The car was not in the right place, but it is one of those very specific things about Spa where if the drivers have not got the car doing what they want, it can cost them a lot of performance.

"It was exactly the right thing for us to just revert to that known specification."