Red Bull technical director Pierre Wache has conceded that the team may have hit the ceiling with the development of its F1 car, though suggested the overall limit of the regulations has not been reached.
The Milton Keynes-based outfit has established itself as the benchmark in the latest technical era, with Max Verstappen winning almost three-quarters of the races in that time.
But rivals McLaren, Mercedes and Ferrari have begun to peg back Red Bull's advantage since the Miami Grand Prix, where Lando Norris picked up his first F1 victory, with the Briton joined by team-mate Oscar Piastri, Lewis Hamilton and George Russell in winning races, in addition to Carlos Sainz's triumph in Australia earlier in the season.
Asked in an exclusive interview with Motorsport.com whether the RB20 had delivered as he and the team expected pre-season, Wache replied: "I would say not really.
"We improved compared to last year, without doubt, but we didn’t deliver what we expected in some areas. Especially in the high-speed corners, we expected a little bit more than what we have.
"Without thinking about the competitiveness of the car, so just based on our own references, we expected a little bit more with our tools.
"I think some aspects can be linked to the correlation," he added when pushed for the cause. "We are using quite an old wind tunnel and it can also be linked to the reduced capacity due to our position in the championship [ATR] and maybe also the fact that this is the third year with this type of regulation."
On whether Red Bull was beginning to hit the ceiling with regards to its development path, Wache admitted: "Our ceiling [with one specific concept] maybe, but it doesn’t mean that it is the overall ceiling.
"In this business you take ideas from the others as well. During the past two years people took our ideas, but fundamentally you need the others to find some other stuff as well to make a step. I think that is starting to happen now and that gives you a different ceiling."
Verstappen broke the record for most wins in a single season for the second successive campaign last term, securing 19 victories which included a record-breaking 10 in a row between Miami and Monza.
The dominance was expected by many to continue into the new year and, whilst it did seem to play out that way before the return to Miami, it has been anything but plain sailing for the Dutchman and the team since.
"I think we expected the opposition to come [catch us] earlier, to be honest with you," insisted Wache.
"When we started the 2022 season, we didn’t have the quickest car - Ferrari had the quickest car in the beginning of 2022. We expected a massive competition in 2023, but that didn’t happen.
"We also expected the competition to be there more or less from the start [this year]. We expected the others to be very close because the performance you can find with the car is of course limited under the same regulations. After the first four or five races the others came back, maybe with an offset and a bit of delay, but we expected that from the start to be honest."
Asked if the gap closing was more down to rival improvements or Red Bull's smaller-than-expected progress, Wache said: "I think it is both together.
"The limitations you have with these regulations are quite high and what you can find to make more steps is getting more difficult of course. Then it is almost sure that, because you keep the same regulations, the opposition will come back at some point."
