Is there any real difference between the cheap and expensive cycling helmets? Is it really worth buying a helmet at say 3 or 4 times the price of a cheap helmet? Will that helmet really give you 3 or 4 times more protection?
No, usually expensive helmets are lighter and more comfortable because have more ventilation.
So, if you plan to ride for long hours it's better to buy the more expensive helmet that you can afford, otherwise - for short rides - a cheap helmet will do the job.
The Bicycle Helmet Safety Institute did a impact test of two sets of helmets. One of them cheap (US$20.00) the other expensive (US$200.00). The results are clear: there's no difference. Buy from a reputable brand.
- If it has the U.S. CONSUMER PRODUCT SAFETY COMMISSION (CPSC) label
- If it is confortable in your head (you'll use it more)
BTW, they give nice and reasonable tips:
"Beware of gimmicks. You want a smoothly rounded outer shell, with no sharp ribs or snag points. Excessive vents mean less foam contacting your head, which could concentrate force on one point. "Aero" helmets are not noticeably faster, and in a crash the "tail" could snag or knock the helmet aside. Skinny straps are less comfortable. Dark helmets are hard for motorists to see. Rigid visors can snag or shatter in a fall. Helmet standards do not address these problems--it's up to you!"
Their site is really informative. It's worth to spend half an hour browsing it.
There is actually some misinformation here. It is true that both cheap and expensive helmets must conform with CE-certifications and EU-regulations etc. but the Swedish insurance company Folksam did a more comprehensive test of bicycle helmets. While the best helmet was a relatively cheap one (if you don't consider the airbag helmet), there was a large difference between the amount of protection they each offered.
Here is a link to the test, but unfortunately it is in Swedish. Google translate was not to keen to parse the link either.
Of course the manufacturers trade on that, but would you trust a helmet that cost a meagre amount?
The more expensive helmets are generally sculpted and designed to have more ventilation, be lighter, be more adjustable, be more comfortable, but ultimately, do you trust them to do the job.
I wear a helmet because when I race I have to and when I commute I'm under personal pressure to wear one. (To be fair I did recently have a crash and my forehead would have looked worse had I not been wearing one - it at least protected me from a longer cut.)
Personally I spent more money because I wanted light and comfortable, but I also figure that something that costs the same as a big lunch cannot have been designed, tested and built properly.
From the same manufacturer (or similar reputable) the safety is the same.
This years model costs more, mostly to make up for selling last years model at half price! The top end ranges do have better ventilation, more comfortable or more adjustable padding and straps and have a logo on the box that says they were endorsed by this years Tour de France winner (unless they have just been caught taking drugs)
Personally I buy last year's model from a reputable maker when the LBS has them on sale.
Since helmets need to be replaced every few years (the plastic degrades) I don't worry about how long a better quality helmet will last. For me the padding and straps become horribly degraded from sweat long before the impact foam chemically degrades.
I also buy two helmets for summer use and alternate them so they at least have a chance to dry out. Older ones get relegated to winter use with the padding removed when I wear a hat.
As long as it meets EU/US minimums, price does not make much of a difference safety-wise; a cheap helmet will do a fine job of protecting you:
More money gives better ventilation, aerodynamics and comfort but you should question whether a shaped bit of plastic foam can justify a £200 price-tag or if you're just paying for the brand.