Chain breaker....why, how and what now?

[BarHugger]

Excuse the topic heading but I need to get some comments (read ideas/advice) from the specialists on why a chain will snap (break). During a MTB race the weekend that include some hard "cranking" the chain suddenly just quit on me during a steep climb while shifting gears to keep cadence steady.

 

The details are as follows:

Chain:KMC X10SL Ti-Gold chain (Manu-notes: only 240 grams for a 116 link chain, with hollow pins and dual sided hollow slotted plates,Titanium Nitride coating)

Chainwheel: SRAM XO Carbon 39/26

Cassette: SRAM PG1070 - 11-36T

Total km wear: less than 200km (bike still brand new)

Rider weight approximately 105kg (excluding my "5-day trek" backpack and garage kit).

 

The specific chain pin seperated from the plate and the link looked like a flower blooming in spring time......you have to keep the humour when stuff like this happen while you are seriously fighting lactic acid "double shots" and shortness of breath. It does not help having an impressive chain (with gold bling) on paper, but when the going gets though it decides it has had enough. Is there a rider weight limit on chain also as in the case of rims?

 

Comments and ideas please..........

[kosmonooit]

Not quite an eggspurt, but were you shifting under power?

[RocknRolla]

there are those far more knowlegable than myself here, but i will share my experience.

 

If the chain is closed using a pin, that is broken off after inserted, then i would say that may be the culprit. If the pin was inserted past a certain point, it may not be as strong as it should be.

 

The other scenario is once a chai has seperated like you describe, and one uses a chain tool to remove and re-insert the rivet, that rivet becomes a weak point, because the burr has been compromised.

 

To be absolutely 100% sure, make use of a quicklink, or masterlink. Keep a couple in your garage pack, using these gives peace of mind.

 

200km is not a lot of milage on the chain, and to me it sounds like you may have just cranked too hard under the situation, and the weakest link in the chain gave up.

 

Also make sure your chain is clean and well lubed prior to each ride.

 

 

[Ysterperd]

Not quite an eggspurt, but were you shifting under power?

Simple physics really - energy applied had to go somewhere and in your case it translated into broken chain, try shifting down before engaging any serious climbs

[Sidewinder.]

105kgs+shifting under power+lightweight chain? I see a problem there

[kosmonooit]

Simple physics really - energy applied had to go somewhere and in your case it translated into broken chain, try shifting down before engaging any serious climbs

 

So you concur this might be the reason?

 

Only time I have ever broken a chain was shifting down under power (Esselfontein 2005), its basically a know-no, and if you are not in the right gear in a climb (as one often is), you have to ease off the power before your try to change gears, or even stop to shift down rather that crunch your gears and put undue lateral stresses on the chain plates and pins

[rouxtjie]

Have never popped a chain myself, but on rides where mate's chains did break it is always

 

Cross chain shift under load on a link where the chain has been broken and new pin wasn't inserted correctly.

 

To eliminate, use masterlinks instead of pins supplied with the chain and obviously shift properly.

[Guest Smimby]

It is not the power or shifting under power that breaks it. That is only the last straw.

 

A manufacture problem, or as some said here using the pin type to join the chain.

 

Always use a master link.

 

More than likely it was one pin or plate that was just as been said the weakest link in the chain.

 

Before I get flamed, think about what power the pro's put down in a sprint while shiffting.....

1000-1800 watts.

 

None of us get to that power, so it can not be power alone.

[Kranswurm]

Have never popped a chain myself, but on rides where mate's chains did break it is always

 

Cross chain shift under load on a link where the chain has been broken and new pin wasn't inserted correctly.

 

To eliminate, use masterlinks instead of pins supplied with the chain and obviously shift properly.

 

I also have never broken a chain.Cross chaining and shifting under power biggest causes

I remember Robbie MacIntosh drumming it in ....soft pedal when shifting

[BarHugger]

The chain break occured half way of a 65km race. Fitted a quick link and finished the race although at a very sedated pace as my confidence in the chain's durability was not very high.

 

Chain was lubed well and clean.

 

Every incline thereafter was started with easy gearing and a lot less momentum (bummer).

[jatho]

Probably the only component on a bicycle not worth trying to cut the weight on is the chain!

 

Its just not worth the risk, stick to well known brands, use master links, check and replace your chain when worn and ease up on the power when shifting and you'll avoid mangling the family jewels.

[Madlight]

Sorry, can't help myself and I have to say it to your bling chainlink..... "You are the weakest link, good bye!"

[BarHugger]

Here is the culprit

[Bitsy]

Hi guys,

 

Went out for a ride yesterday and snapped my chain

The bike is new and has done only 300km thus far.

 

It was probably my fault since i tried to change up on the RD on a really steep climb. The chain snapped whilst I changed and stood up on the bike to get some extra power. Was also on the outer gear of the FD.

I was on a club ride so got some assistance from them and fixed the chain with a link pretty quickly. I have two questions.

 

1. Do i need to replace the chain now or will it still last...its a KMC 11sL

 

2. I see the link we put on is a 10s and I have an 11s....is there really a difference between the two?

 

Rgds

[Fisan]

Hi guys,

 

Went out for a ride yesterday and snapped my chain

The bike is new and has done only 300km thus far.

 

It was probably my fault since i tried to change up on the RD on a really steep climb. The chain snapped whilst I changed and stood up on the bike to get some extra power. Was also on the outer gear of the FD.

I was on a club ride so got some assistance from them and fixed the chain with a link pretty quickly. I have two questions.

 

1. Do i need to replace the chain now or will it still last...its a KMC 11sL

 

2. I see the link we put on is a 10s and I have an 11s....is there really a difference between the two?

 

Rgds

 

2. 11 speed chains are slightly narrower than 10 speed...as 10 speed chains are narrower than 9 speed chains. The 10 speed link was sufficient to get you home, but I'd advise to get an 11-speed quicklink from your LBS for a smooth running drivetrain. Just 40 bucks or so. Here's a readup on the "chain-width" I'm referring to.

 

1. Your chain will last it's full lifetime with the 11speed quicklink. If you are running a KMC chain you probably already have a quicklink in there - that is the way they are installed (compared to Shimano's master pin method)

[JXV]

Here is the culprit

When removing a link to shorten it or to push in a new joining pin, the precision of the chainbreaking tool is a major factor. It is easy to bend a side plate or push the pin too far/not enough. That joint will always be weaker. I far prefer using masterlinks/quicklinks.

 

My old professional Shimano chain breaker is of superb quality but was made for 8 spd chains. It works ok on 9spd but I have had several issues joining 10spd chains with it. 10spd is narrower and the tool does not hold the side plate on the far side properly. So maybe the tool used to link that chain is also part of the problem.

 

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