Even a small drop can have unseen consequences that mean your helmet is no longer as safe as it was when new. Helmets are designed to absorb the shock of an impact, saving your brain from damage. A helmet that rolls off a sofa and onto a carpet is likely to be ok. A helmet that falls off the seat of your bike and hits the pavement is not likely to be ok. Imagine it’s your bare head in each case. Your head will bounce unharmed on carpet, but you could be badly hurt by hitting your head on the pavement, even at low speed or a short height. Even if there is not a mark on the exterior of the helmet, cracks in the hard shell of the helmet may not be visible, or the padding inside could have been affected by a fall. If you were to have a crash while wearing this damaged helmet, it simply may not protect your head in the way it is intended to. This is a big risk to take. Our best advice is that if a helmet has fallen onto a hard surface, it should be replaced as soon as possible