Boomerang is key to new BMW 1 Series dynamics

Engineers of the third-generation BMW 1 Series have seemingly looked to the Australian Outback when it came to developing the chassis design of the Bavarian brand’s first front-wheel drive hatchback.

Speaking to carsales.com.au at the global launch of the all-new BMW 1 Series this week, Project Manager BMW 1 Series Driving Dynamics Andreas Stumm said a new boomerang-shaped cross-brace in the rear-end of the front-drive hatch was pivotal in providing the sort of handling dynamics that were synonymous with its rear-drive predecessor.

“We wanted to have the new 1 Series [feel] sporty and direct, so it’s responsive,” said Strumm.

“Based on the [UKL] front-wheel drive platform, we wanted to have it as neutral as possible for a front-wheel drive, that’s why we added components such as the torsion differential and this boomerang-shaped cross-brace at the rear.”

Stumm explained that the brace – which connects the rear suspension to the floor below the rear footwell – helps deflect some of the vertical and torsional load from the 1 Series’ multi-link rear suspension back into the chassis. The idea is to distribute that movement into the body to promote a more neutral yaw moment than would be achieved otherwise.

“You need a certain base stiffness in the body, which we have. But if you have the balance not right, then it’s actually acting like you have different roll bars,” explained Strumm.

“In a front-wheel drive, when that balance is not spread over the whole body length in a correct and continuous way, then it will feel like [there’s] a very big stabilisier bar at the front, and a very small one at the back.

“Then, you try and compensate by adding a thicker roll bar at the back and that creates other unwanted movement like body roll.

“In that instance the suspension is not working properly anymore – that’s why we’ve made so much effort in developing this boomerang-shaped brace in a range of sizes depending on the variant.”

BMW said it wanted to give its first front-drive 1 Series a tune that was more recognisable to that of the previous model, without detracting from the ride quality buyers expected.

The UKL2 architecture on which the new 1 Series is based is shared with the majority of the latest MINI line-up, but Strumm said clear differences were required in consideration of the buying demographic.

“One of the main basic points was to have a sporty feeling,” Strumm added.

“As one of my tuners said: we want the car to ride comfortably over a bumpy road, but there still needs to be a firm connection between the road, the car and the driver. That’s one of the main targets.

“But it’s difficult to balance a customer's expectation nowadays. The entry-level BMW buyer may be new to the brand, and you don't want to scare them away by having it [the ride] too sporty, too direct or too stiff.

“We had a discussion on this point and how we wanted to have it, and we think the result is the right decision,” Strumm concluded.

Whether or not critics or buyers think the suspension tune of the third-generation BMW 1 Series is ‘right’ remains to be seen. Visit carsales.com.au again this Wednesday (July 17) for our first review of the new BMW 1 Series.