ooOOoo – thats not when it increases the rotational force – its tangential or oblique blows not straight on ones.

there is also the effect that skin slides over bone so dissipates the force – the hard plastic of the chinbar does not do this

all shown experimentally.

I see your point, but crashes are random messy events.
My friend's helmet was cracked after, so I imagine some of the forces were dissipated through the chinbar into the helmet, not his chin.

There definately is an possibly increased risk from the rotational forces the chinbar can impose. But, this was one of the arguments that was used to try to resist mandatory motorbike helmets "They'll cause lots of broken necks". The theory's sound but the real life impact (no pun intended) hasn't really borne out that there's a major risk. Obviously motorbike and pushbike use doesn't directly compare in a lot of ways, but it's one of the few useful parallels we have.

(TJ might well say "motorcycle chinbars don't stick out as far". It's true, but the difference is marginal and the difference in impact speeds more than makes up for that difference, you're never likely to hit your face at 100mph in a Parachute)

It's also no more risk than with any proper full face helmet- so would the people saying the Met is dangerous say the same applies to a Deviant, or a Rampage, or a D2? Perhaps they would but you don't see a lot of DHers with that opinion.

(for the record I don't own and don't intend to own a Parachute 😉 But not because I consider them useless or dangerous)

Fair comment northwind – motorcycle helmets are also much smoother shells

What I dislike about the met parachute are 3 things – the general case about ff helmets, the fact that the chinbar has all those holes and angles to catch on things and the fact that it is made of plastic with no poly to absorb impact.

its only opinion tho. a fair amount of reading and data behind it but it remains opinion

As for neck breaks – a couple of folk on her have had fractures ( but no nerve involvement) and that doc from the southern general hospital recorded IIRC 8 serious spinal injuries from MTBers. Thats enough to scare me

Yup, but then most of those people will be sustaining those injuries with standard helmets (or in some cases possibly with no helmets at all). Some might even be lower spine injuries so not influenced at all by helmet use. I know you probably know this, more stating it for the jury 😉

The polystyrene in the chinbar of a motorbike helmet doesn't do much fwiw, the impact absorption from a frontal hit comes mainly from shell deformation, and from the foam elsewhere. The poly only really comes into play when it's in contact with something solid, ie, a head. The poly layer in the front of my Arais is vestigal, and even then it's hollow as it's full of vents.

You can still buy the Casco Viper & its not a bad bit of kit. The chin bar is fairly snug & padded with foam.
clicky
I for one am happy to wear it.

As for neck breaks – a couple of folk on her have had fractures ( but no nerve involvement) and that doc from the southern general hospital recorded IIRC 8 serious spinal injuries from MTBers. Thats enough to scare me

Don't worry considering the speed you are going you are free for any rotationnal injuries 😉
Plus I can't help but wonder if the spinal injuries were due to rotational or direct forces (like falling directly on your head) and did the helmets really increased the injuries (I know you are going to quote me an article from the old age of some nerd playing with cheap asda helmet and a dummy head).

Problem in the helmet data is:
There is nothing very new in term of studies and testing.
There is no data from the helmet manufacturers (I would like to know the number of helmet that goes trough crash replacement whom rider is NOT injured).
I think snell should test all the helmets as well

Juan – perfectly valid points – real good data is in short supply.

Rotational forces can be shown experimentally but there is no data on "real life" situations from cycling.

cheesy beans posted a link earlier in the thread (a specialized) helmet..close chin guard looks like a motorbike helmet but (not)..

ED Oxley ::: yep I know we all go over the handlebars, its even more so in the wet mud ive been flying over ! my front wheel just gets stuck in glupe and im over the bars in a split second… lol…. just looking for that 'extra face' protection relly and wanted some advice on the best helmets i guess… gud job i was wearing my knee pads cos if i hadnt then i wud have had two busted knees by now !

CheezyBeanz linked to the Specialised Deviant Carbon.

Its a proper but well vented DH full facer and as such will be heavier and warmer than any XC lid – IMO its about as useful as an XC helmet as the Met Parachute (or Casco Viper) is as a DH helmet.

DH helmets should be a good, tight fit, like motorbike helmets and that is one of the main reasons they are not that good for XC – having said that I've known people do pretty long XC rides in Full Face helmets (although don't tell the helmet-police that they didn't wear them on the climbs).

Also if you're going to wear one of these helmets then be prepared for the "storm-trooper" type mockery the fashionistas will dish out.

OK I've had a met parachute for the last few years, and I've some actual crash experience of it. Firstly it fits like a good XC lid and is very well ventilated & light enough not to matter. Its been through several hot(ish) summers and i use it daily for my commute.
Most of my riding is Calverley / Esholt woods on the edge of Leeds, with some entertaining jumps and small rock gardens to come off in, and we ride all year round, nights too – so crashes have happened.

The Mets additional chin protection is flimsy compared to a full face, but XC & less full on jumps are well within its competence – certainly enough to keep my jaw / cheekbone in one piece in an oblique impact with a boulder after botching a landing & flying over bars (at night! not my fault!)
The vertical impact was saved by 661 racelite knee & elbow armour (thanks guys), but i slid into some nice big rocks & used them as a brake to stop, mainly with my right wrist & left cheek – result: broken radius at wrist end, but an nice intact face.
I think the issue here is that the Mets design gives much better cheek & jaw protection than a normal XC lid, but if id faceplanted directly onto said rocks it might have been a lot messier, but who knows compared to a FF like a deviant, since i dont particularly want to do it again…
Anyway I too am looking at something more substantial since im now on a 5.5" SC blur LT rather than a 4" XC bike & these sorts of things are going to happen again…

Ed-O, do you run a "falling off and how to land without using your chin as brakes" course?