Aero or conventional wiper blades: which should I buy?

How each design works

Aero or flat blades

A flat blade has no external frame. On Bosch's Aerotwin range, two spring strips made of Evodium steel run inside the blade and, in Bosch's words, adapt to the curvature of the windscreen as it wipes. A spoiler runs along the whole length, which Bosch says stops the blade lifting off the glass at higher speeds and cuts wind noise.

Conventional or framed blades

A conventional blade holds the rubber in a frame of metal brackets that spread the arm's pressure across several points. Bosch describes its Twin range as a robust full metal-bracket system, with a two-component rubber and a Quick-Clip adapter. Some Twin blades add a spoiler, which Bosch says improves high-speed behaviour.

The differences that matter

All figures are from Bosch's UK wiper blade page. They are the maker's own descriptions, not test results.

Fit is model-specific

The design debate matters far less than fit. A blade has to match your car on three points: the length of each blade, the connector on the wiper arm, and, for some sets, the side of the car the driver sits on. Bosch's Aerotwin range alone comes in four adapter variants (Original, Universal AM, Universal AP and Upgrade AR), and they are not interchangeable on every arm.

Measure your current blades or look your car up before you buy. Our wiper blade size guide shows how to measure, and thewiper blade buying guide explains connector types.

Common mistakes

• Buying by length alone. Two blades of the same length can have different connectors.
• Mixing up the two blades. Check which blade goes where before you remove the old ones.
• Buying a left-hand-drive set. Some sets, like the Aerotwin A864S, are listed for right-hand drive only.
• Switching to a flat blade on an arm built for a framed blade without checking the maker lists an upgrade for your car.

Related reading

• How to measure wiper blade size
• Wiper blade buying guide
• Our wiper blade picks
• More about Bosch

Frequently asked questions

Are aero blades better than conventional ones?

Bosch claims advantages for its flat Aerotwin blades: Evodium spring strips for even pressure on the glass, and a spoiler along the full length that stops the blade lifting at speed. It also describes its conventional Twin blades as a robust full metal-bracket design for all weather. We have not found independent measurements comparing the two, so buy the type your car is designed for unless the blade maker lists an upgrade for it.

Can I fit aero blades to a car that came with conventional ones?

Sometimes. Bosch sells an Aerotwin Upgrade range with a pre-assembled adapter for upgrade, but whether it fits your arm depends on the car. Look your registration or model up in the blade maker's catalogue rather than assuming any flat blade will clip on.

Why are my two front blades different lengths?

Many cars use two different lengths at the front. The Bosch Aerotwin A864S set, for example, is 650 mm and 450 mm, and the Twin 613 set is 600 mm and 350 mm. Match both lengths and the connector, not just one.

Does it matter that a set says right-hand drive?

Yes. The A864S product listing says it is only for right-hand drive (UK) cars. A set made for left-hand drive may not suit a UK car, so check the listing and the blade maker's catalogue for your model.