Bicycle Helmet Covers
Summary: Helmet covers can add color and warmth to a helmet. They may make the helmet more attractive to kids. They should always be made to slip off readily in a crash, or they could contribute to sliding resistance. We don't like the ones that add projections to the outside of the helmet.
New helmet covers appear regularly. The fashions change and can be both attractive and fun. Kids may appreciate them for that. For many riders they reduce the air flow enough to be more than just warm, and a sweaty head can result, even in cold weather.
Thin nylon or Lycra covers that are held on with elastic bands around the bottom are probably ok, since research years ago showed that they just slip off in a crash, and with the old foam-only helmets of that era they were actually beneficial for sliding for the first inch or so. But today's helmets all have smooth plastic outer shells that already slide well. The cover may interfere with that, and we have no testing to verify the effects on a current helmet. We have never seen any lab tests of the ones with horns or other projections, so you are on you own with those, but we would not use them. The key is to make sure the cover slips off readily. You can verify that by putting the cover on, holding the helmet firmly down on pavement and scraping it hard. Of course, you will scratch the cover or the helmet shell doing that.
We would have reservations about any cover that has pieces that come down and wrap around the neck like a scarf. In that case the cover could be held on by the scarf, and would probably add to the sliding resistance of the helmet. The same comment would apply to any design that held the cover on so tightly that it could not slip off. No cover material is likely to slide as readily on pavement as the helmet's plastic shell.
For more on why you want you helmet to slide on impact, see our page on sliding resistance.
In the absence of lab data, we are always on the lookout for field reports on covers and how they perform in a crash.
You will find links to a few helmet cover sources on our Links page.
This page was revised on: October 25, 2020.