Snapped chain - how common?

[Globalti]

Did a 75 miler with 5700 ft of climbing yesterday (Cross 'O Greet in Bowland) with my cycling buddy who is a strong rider. All the way round he was having trouble with his gears so we decided we would start with a complete cable replacement this week, to try to cure it. However when we stopped 5 miles from home to go our separate ways I glanced down and noticed that one of the links of his chain had snapped on one side and was hanging on by the other, ready to go. Then as we examined the chain we spotted another link where the side plate had snapped cleanly from the pin outwards towards the edge.

There is no recognisable brand name on the chain, which he bought from his LBS (a bloke I don't like at all) about 6 months and 1000 miles ago. I told him to take it back and try to shame the bloke into giving him a new chain but a decent brand or at least a good discount on a new chain.

Surely a chain ought to be able to withstand a strong amateur rider? After all they can withstand a professional rider. Could the two breakages have been the result of fluffed gear changes? He is in the habit of sprinting up short hills, changing gear under some stress as his speed drops.

 

[jay clock]

happens generally when the chain has been broken and rejoined. I had almost exactly the same problem a few mths back. The day before a 100mile ride, I had dodcgy gears, so changed all the cables etc. 2 miles in the chain went. My fault for breaking and rejoining it.

 

[amaferanga]

His trouble with the gears probably caused it. If he was putting the power down while the chain was between sprockets it could easily have contributed to the broken link.

 

[Globalti]

This chain hasn't been broken and rejoined - it has just broken!

 

[Flying Dodo]

His trouble with the gears probably caused it. If he was putting the power down while the chain was between sprockets it could easily have contributed to the broken link.

More likely the other way round. One link starting to come off, and so partially jamming the chain.

If a chain is split using a chain splitter tool rather than a quick release link, you're likely to incur problems at some point. Even if the cheap chain hadn't been split, I'd stick with using a decent quality chain.

 

[Cheule]

I've only ever had one chain snap in 31 years of riding, back when I was barely a teenager on my BMX. So, quite rare!

 

[actonblue]

It has a happened to me twice in 15 years on commuter bikes and both were due to bad gear changes.
We all ride in different ways and have different effects on the chains so we will all get different performances from them.

The day before a 100mile ride, I had dodcgy gears, so changed all the cables etc. 2 miles in the chain went. My fault for breaking and rejoining it.

Why would you split a chain to change your cables?

 

[LizardEye]

I've snapped two chains in the last couple of years, both of them fairly new, and both times due to dodgy gear changes. The chain is very strong when it's straight, but any major force such as standing on the pedals when it's not in line or when between sprockets can easily snap it.

Your mate really does need to be careful when changing gear, and only put the power down when it's firmly in the right gear.

 

[RedBike]

Its actually quite common for chains to snap on MTBs.

Dirt and grim gets in the chain so they stretch and wear at an alarming rate.
Then the rider tries to change down a handfull of gears quickly while pedalling hard. The chain snags, twists and then snaps.


There's always some poor sod at the Merida MTB events with a snapped chain.

 

[Crankarm]

I've never had a chain snap in 3 decades of riding. They snap because 1) they haven't been joined properly 2) the rider doesn't have a clue about changing gear smoothly, more than likely prematurely putting power through the cranks as the chain jumps to a new sprocket thus causing crunching of the gears and 3) the rider routinely uses the large outer big chain ring at the front with the largests sprockets at the back. This will loosen the side plates of the chain which will cause it to snap under heavy load and also prematurely wear the teeth of the big chain ring and largest sprockets.

Chains don't cost a lot even a decent one. Just dip into your wallet, sorry tell your friend to dip into his wallet and buy a new chain. If he wants to preserve the life of this new chain and his bike's transmission generally he would do well to treat his bike more sympathetically when changing gear. Perhaps he genuninely is a numptee and doesn't realise the effect his poor gear changing is having on the longevity of his bike's transmission?

If I was the LBS owner I would tell him to sling his hook.

 

[HLaB]

When I was a kid I had my old Raleigh mtb chain snap after only a few hundred miles but I was stupid enough to been using WD40. I had a no name chain snap on my old hybrid after several thousand miles before I really knew about maintenance. I got 2000 miles out of the SRAM chain on my current Hybrid before it snapped but touch wood the better maintained road bikes have never experienced a chain snap (the Kinesis has had a chain the longest in terms of distance, it sits at 5250 miles, a 105 chain).

 

[Globalti]

I've never had a chain snap in 3 decades of riding. They snap because 1) they haven't been joined properly 2) the rider doesn't have a clue about changing gear smoothly, more than likely prematurely putting power through the cranks as the chain jumps to a new sprocket thus causing crunching of the gears and 3) the rider routinely uses the large outer big chain ring at the front with the largests sprockets at the back. This will loosen the side plates of the chain which will cause it to snap under heavy load and also prematurely wear the teeth of the big chain ring and largest sprockets.

Chains don't cost a lot even a decent one. Just dip into your wallet, sorry tell your friend to dip into his wallet and buy a new chain. If he wants to preserve the life of this new chain and his bike's transmission generally he would do well to treat his bike more sympathetically when changing gear. Perhaps he genuninely is a numptee and doesn't realise the effect his poor gear changing is having on the longevity of his bike's transmission?

If I was the LBS owner I would tell him to sling his hook.

Well, he's ridden 8000 miles in his recent life without this happening but yes, point taken. My guess is that his cables have deteriorated causing the shifting problems which has caused the damage to the chain. We are changing cables and chain this evening.

 

[ColinJ]

I've been with 4 or 5 riders who have snapped chains on rides. That's probably in over 100,000 rider miles, so I'd say it is pretty rare if you fit good quality chains properly, keep them clean, use your gears sensibly and change the chains before they get too worn.

I got a mate into cycling. At the time, he had just given up body building so he had very big, powerful leg muscles and rode everywhere on the big ring, sometimes with a poor chainline. He also had a very bad 'mashing' pedal stroke where he put enormous power down very briefly twice per revolution of the cranks. I'd been telling him to make better use of his gears but he poo-poohed what I was saying. We then hit a section of 8% and he was doing his best to kill the bike so I shouted at him "For God's sake, use your gears and stop mashing or you will..." BANG! (My words were drowned out by the sound of his exploding chain!) "... er, destroy your transmission, just like that!"   

 

[e-rider]

A decent chain correctly put together will almost certainly never break.

The most common reason for chains snapping is incorrect joining - either re-using a standard pin and not using a special joining-pin or not putting the connecting pin in correctly. It's amazing how many people think they can just pop out any chain pin and push it back in again - 5 miles later and 1 broken chain!!!

Almost every chain available today will have either a connceting link or a special connecting pin. The links are pretty much fool-proof. The pins (think Shimano) must only be used once and never removed after fitting. If you need to break the chain at a later date, push out a different link and then re-join using a NEW SPECIAL JOINING PIN - this must be done EVERYTIME!

 

[numbnuts]

When I was a kid I had my old Raleigh mtb chain snap after only a few hundred miles but I was stupid enough to been using WD40.

WD 40 is all I have used and I get about 6500 miles out of each chain, I do clean it on a regular interval and spray between rides, most of the time I sit and spin so this may have a bearing on the mileage I get from each chain.
ps never had one break.......as yet