My kids chain snapped while out yesterday and I’m wondering whether this is a defect or is it just stuff that happens?
I punched out the broken link and put a quick link there instead but when I had it out I checked the whole chain and like where the arrow is pointing there are micro cracks on the outer plates on like 5-6 links. The chain is less than a year old on a wholly new drive train, Shimano original, and well the kid is a kid so hasn’t got many miles on it. Not worn at all.
Is it down to kid shifting under load? Defect product or just bad luck? Is this preventable at all?
by Swedischer
8 Comments
Whatever it is, id replace that chain asap
Where did you buy it? Amazon and eBay are flooded with fakes.
kid shifting under load damaged the chain? clark, is that you?
this happens, could be defect of this chain. my kmc seller provided a six months replacement warranty. shimano non-top range products have two years warranty. if you are really in a tight spot right now, you may try your luck with shimano or your seller.
Did you ever wash it with a product? Chemicals can cause embrittlement if too harsh, or improperly used.
I had something similar on a KMC chain, I believe degreaser baths had something to do with it.
My assumption is that if it was a quality control issue then it would have just broken at the defective link. And if chain was under too much torque then surely it would have snapped the first or second time the chain was compromised, not the fifth.
Maybe the chain is old and it was too stretched out.
When was it purchased? Bike parts produced during covid had sometimes funny quality. I just returned tyres which after less than 2 years got completely dry-rot (low mileage, bike stored inside).
There’s no chance that your kid destroyed the chain, it’s not a kid-chain, this should last 2000 km including mountain trips by 100kg+ strong dudes. Either the store managed to get themselves a fake or the quality control was none.
Check the rest of the bike carefully – especially rims, around nipples. If there are any cracks there – it’s unsafe to ride.
I’d call it a manufacturing defect, its possible to break good chains like this with a lot of power and shifting under load, but if your kid isn’t named Clack and crash-landed on your farm in a spacecraft he shouldn’t be strong enough to do this.
For reference I’ve put 1000w of ebike motor plus my own strength trough chains and shifted under load until chain is stretched way past 1.0 wear and both cassette and chainwheel is worn out and the chain was still holding up until it started skipping on worn out cogs. Still no breaks.
Really strong people with clipless pedals (or really heavy people with flats I suppose) can break good chains by pedaling, but you have to be **strong,** if you’re not its a manufacturing defect.
Shimano chains are usually dependable, but manufacturing defects can still happen.