MET Sine Thesis helmet review

Well-made helmet that's high on style but has issues with comfort

Our rating 
2.0 out of 5 star rating 2.0
GBP £189.99 RRP
MET Sine Thesis helmet

Our review

A sharp design that’s well made and very tough, but suffers some comfort issues
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MET was an early exponent of in-moulding for the outer shell of helmets, and this continues under much of the lower edge of the Sine Thesis, although some parts still lack complete protection.

  • Highs: Bold styling, upper silicone pads
  • Lows: Brow pad, strap position, comfort

Long vents and angular styling with bold colours are unmistakeably Italian. Those long large vents force a lot of air through the helmet, cooling superbly via the deep internal channels. There’s lots of options for sunglass storage when climbing too.

The snug overall fit is helped by the minimal silicone pads, but there is one hard rear section behind one of the pads, which rubbed against our head and really wasn’t comfortable for testers with larger, more-rounded heads. The large silicone brow pad presses evenly against the skin though, and doesn’t heat up as much as a normal pad.

The rear cradle has four height adjustment stops and fits quite low, with a rotary dial to adjust the size, which is simple to use, even on the move.

The ventilated straps keep the helmet’s overall weight down, but they unfortunately exit the rim of the helmet at the temple at an angle that forces them to twist, and present much of their profile to the wind.


Comfort wasn’t great – we found we would often catch even short hair in the rear cradle when putting the helmet on, and the silicone brow pad does leave parallel lines on your forehead. It didn’t feel very comfortable on the bike either, there a few unwelcome internal edges, which were hard to ignore.

Product Specifications


Name Sine Thesis Helmet (14)
Brand MET

Description Weight 339g for large size : ip-up neoprene case included
No of Vents 22