Injuries from a broken chain?

[lucas]

Hey, so I've been told that if you run a motorcycle without a chain guard you can get your leg torn up if the chain breaks.

Upon hearing that I had to find pictures and video of the carnage... But I found nothing.

Is this a myth?  Looking at my chain it is hard to imagine it twisting in such a way as to reach my leg.

[Janx101]

The question you have to ask yourself is do you wish to risk it?

Different chain but look up chainsaw injuries

Also. .   Maybe your leg is safe from chain impact itself, but the guard also prevents it from getting caught on other bits of bike if chain breaks

Chain causing rear wheel lockup is also undesirable!

[fetor56]

Lucky or unlucky.....personally i would rather restrict a chains field of movement if it breaks.

[Joolstacho]

If it does let go, look at what damage it could do to engine casings etc. Why would anyone risk that?

[Big Rich]

Ugh.... I did a Google image search for chain injuries. That lasted all of 30 seconds.

Lucas, every time I've heard of a chain injuring a leg from a first hand witness, it was always from a older gentleman (and usually associated with racing). Maybe a couple decades ago when removing the chain guard for racing duties on lower tech and / or abused chains had something to do with it? Obviously just guessing.....

I do remember on picture I saw on a blog.... I believe it was on "La Zone Noire"? But it was an older race bike and when the chain snapped it was shooting straight up off the rear sprocket when the picture was taken. Looked like the bike had a scorpion tail.

[Alan_nc]

You will have trouble finding a used 125 or 250 dirt bike that doesn't have engine damage from a broken chain.  They tend to wrap around the front sprocket when they break.  Usually not much damage to the rider.....but I don't think I would chance it.

[crackin]

It's a myth. Million to one chance of being hit.
The chance of engine case damage or back wheel lock up are extremely high regardless if you have a guard or not.
Just my opinion from 30 years of experience.

[fetor56]

You will have trouble finding a used 125 or 250 dirt bike that doesn't have engine damage from a broken chain.  They tend to wrap around the front sprocket when they break.  Usually not much damage to the rider.....but I don't think I would chance it.

I was scramble riding with a friend and his idea of routine maintenance was to routinely add fuel.
As i was trying to manoeuvre to overtake we went over a high dirt jump and he landed with his broken chain wrapped around his front sprocket.He fell heavily and injured himself badly;hospital for one week.
Since then i'v had even more respect for rogue chains,road or non road.

[lucas]

Seems to me a chain guard is not going to prevent a chain from wrapping a sprocket, front or rear.

Best I can figure the chain guard will keep the end of the chain from hitting the engine case above the sprocket.  How critical is this prevention?  If the motorcycle is driving along at 70mph the end of a broken chain will travel forward at 20mph.  That kind of impact on an engine case doesn't seem very scary to me.  Am I missing something?

Again, I understand that a chain wrapping the sprockets can cause accidents.  But the fact that a chain guard does not prevent wrapping means that should not be a factor in discussing if chain guards are an effective safety device.

I noticed that someone stickied a chain guard "PSA", and that thread had gone ignored ever since and just pushes the current threads down farther on the page.  That thread does not and likely will not contain any relevant information beyond personal anecdotes.

[sledge]

How a snapped chain will behave is unpredictable, loaded or unloaded, top run or bottom run, fast or slow. With the GS5 its usually the clutch push rod that gets taken out.

But something seems to have been completely overlooked here...............If you are two-up it goes some way in stopping your passengers flares getting dragged in

[Janx101]

Leave it off! ... post photos when something nasty happens..   it'll be a learning experience for everyone! ~Shrug~

[Alan_nc]

Food for thought:

Why does every company put one on every bike they make?

[Big Rich]

I can think of three reasons off the top of my head:

1) Liability in case the chain does snap.
2) To stop chain wax / oil from flinging everywhere  (and believe me, it gets everywhere).
3) To help protect foreign objects from getting entangled in the chain.

Number 1 and 3 aren't major concerns for me (although they are very important). Cleaning chain wax that has flung off is a huge pita - that stuff is made to not be washed off easily.

[lucas]

I think some of you might misunderstand the motivation behind my question.  My concern is with learning the actual risks involved in my decisions.  For the majority of my life I had refused to ride a motorcycle because I assumed that I would immediately be ground up into a sticky red pile of flesh.  Since  I wrapped my head around the actual level of risk involved I moved forward with buying a motorcycle and learning to ride.  I was also encouraged to know that I could develop skills that would reduce the risks of death while allowing me to enjoy the freedom of a motorcycle.

If I had kept the "better safe than sorry" reflex I would never have gotten on a motorcycle and my family and friends would have one fewer thing to worry over.

Another thing about me is that I am not squeamish.  I have watched footage of hundreds of motorcycle accidents from low speed low sides to high speed head on collisions and checked out footage of surgeries done on mangled motorcyclists and learned the stories of people who lost limbs or were paralyzed or suffered permanent brain damage.

So when someone tells me that a broken motorcycle chain can tear up your leg I went looking for documentation about how bad these injuries are (especially since I had already discarded mine.)  I can't find even one image or video of someone who has had their leg splayed open, or snapped, or bruised by a hit from a motorcycle chain.  I think I know where to look on the internet, if you know where to look please let me know.  I can find all manner of unlikely but real injuries.  It makes me think that this unlikely leg injury from a motorcycle chain may be a myth.

I'm not saying that there is a conspiracy about motorcycle manufacturers or governments foisting fake safety equipment on us.  But I do know that people can take something that only appears to make us safe and then assume it is necessary.  People do get caught up in folk wisdom all the time and it isn't necessarily reckless for me to all the question if what we "think" is keeping is us safe is "actually" keeping us safe.  Further if a chain guard is necessary for our safety is there a way to make it safer, what are the modes of failure that less to injury, are they all mitigated by the current design?

I find it perfectly plausible that manufacturers of motorcycles would install a chain guard for the sole purpose of keeping lube off the riders and the underside of the bike.  That it sort of keeps the elements off the chain is a plus, but if that were the aim there is a more complete solution to that.  If the goal were to prevent the chain from fouling in the front or rear sprockets there are also more consistent ways to accomplish that.

Maybe it is intended to reduce the number of people who lose their fingertips while cleaning their chain?

I will retract my previous claim that the chain would be traveling at 20mph because I realize now that if the chain is under load when it snaps the engine speed might increase dramatically and speed the chain up. 

So all that said, I am not convinced by recommendations that I take all precautions whether they can be shown to be effective or necessary.  I am also (sorry) not convinced by stories of a guy who heard it from a guy who definitely saw it happen one time and it was utterly ghastly.

I am also of the opinion that if these claims of danger cannot be well supported then they should not take up space on this forum in the form of a sticky.

[Rallyfan]

The actual issue seems to be the importance of chain  integrity. Maybe more emphasis should be placed on the significance of chain oiling and tensioning; both are easy and very low cost. If the chIn does not fail the rest of the discussion is moot.

[Big Rich]

In regards to keeping fingers safe while cleaning the chain: I don't think the chain guard really comes into play for that. The top / outer surface of the chain is "self cleaning" due to momentum. The bottom / inner surface of the chain is what really needs cleaned since it comes in contact with the sprockets. With the wheel elevated and transmission in neutral, I've always cleaned the bottom of the chain (not near the chain guard) by spinning the wheel backwards. Lucas, I'm sure you're seen the pictures of the guy that tried cleaning his chain with the engine running...... THAT guy needed a chain guard to protect himself. Actually, he needed to stop and think about what could happen before putting his hand there.....

[lucas]

Haha, yeah there are loads of those.  A member here hurt himself on his chain last year but he didn't have the engine running.  He got light-headed from squatting while cleaning the chain and tried to steady himself by putting a hand on the rear tire accidentally turning the tire.