The start of F1’s new ground-effect era witnessed some interesting variation in sidepods, with Red Bull one of many to adopt what is known as a downwash design.
Elsewhere on the grid, Ferrari had its in-wash bathtub solution and Mercedes went with its zeropods.
But as teams have come to better understand what is needed to extract the best performance from the current rules set, and also where the best development potential lies, the downwash idea appears to be winning out.
Both Ferrari and Mercedes have shifted their designs in that direction as part of wider overhauls of their cars, which appear to have delivered much-needed steps forward.
Despite that progress and a general convergence on the Red Bull design idea, Allison thinks it wrong to suggest that sidepods are a key factor in explaining the performance of teams – especially as he makes clear that all designs are effectively trying to replicate the ‘downwash’ idea.
“I'd be surprised if there was a sidepod on the grid, ours prior, ours post, anybody, that is not a down-washing sidepod,” explained Allison.
“They've been downwashing for years, and I suspect they'll stay that way for some years too.
“I would continue to suggest that the reason that a Red Bull is beating the rest of us will not be in the details of its sidepod, nor [explains] the uplift in Mercedes’ pace with our upgrade. It’s not really particularly connected to its sidepod either. They’re just not that big a feature.”
But while the overall impact of sidepod design is much less than floors, Aston Martin technical director Dan Fallows does suggest that they are critical to the overall package of performance.
“There's no doubt that the sidepods are essentially flow-tuning features,” said Fallows, whose squad has pushed on with the waterslide variation idea. “They are things that condition the flow to the rear of the car, but it also helps the floor to work as well.
“The philosophy that we've adopted, which is getting wider adoption across the grid now, is obviously something which helps this concept of floor to work as well.
“Although in itself maybe the actual performance improvements of the bodywork is not so big on its own, it helps everything else to work. So it's quite a big feature of the car.”