Shimano Dura-Ace HG901 chain failure

[slo town]

Y'all:

In 50 years of riding bikes I had my first ever chain failure ever today. An 11-speed HG901 Dura-Ace/XTR with less than a thousand miles on it. I was able to make it home but had to soft pedal in the largest cogs because it jumped the teeth on the small cogs. To those of you unfamiliar with this chain, this is not the link I used to close the chain. This chain uses a one-time use master link.

As you can see in the picture the outer link plate at the 12 o’clock position has partially pulled away from the inner link roller. I tried to free up the link on the road but it was jammed solid - and probably just as well too. This chain would likely have broken if I had lots of climbing yet to do, possibly resulting in a ruptured achilles or crushed testicle had I been climbing out of the saddle at full power. Broken chains are no joke.

I'm chalking up the failure to poor quality during the Covid era.

Scott

 

[twouvakind]

KMC chains for me, never a broken one.

 

[MRC01]

Strange failure. Looks like a manufacturing defect that took a few hundred miles to manifest. Thanks for sharing, like a public safety message.
IME, Ultegra has been more durable than DuraAce, even if a little heavier. I dunno if that was a factor here.

 

[Pablo]

KMC chains for me, never a broken one.

That is all we sold for speed chains

We did have some heavier single speed/410 chains in other brands, but due to their beefier size, maybe a bit more room for error. I know that sounds terrible but as noted in OP - the lighter speed chains are serious business and there is no room for error/slop.

 

[slo town]

KMC chains for me, never a broken one.

I may have to try one in the future. I tried a high end Wipperman on Campy Record 10-speed and the shift quality was horrible. That's why I've stayed with OEM chains made for the gruppo.

Scott

 

[slo town]

Thanks for sharing, like a public safety message.

Exactly.

Scott

 

[PeteDaLubey]

what a bummer. they had such a good name for years. genuine Shimano from a bike shop or did you buy it online? Glad u made it home safe and had the sense to soft pedal it back. i have had a couple of chain failures / half fails. nasty events. Hope they replace it for you.

 

[slo town]

what a bummer. they had such a good name for years. genuine Shimano from a bike shop or did you buy it online? Glad u made it home safe and had the sense to soft pedal it back. i have had a couple of chain failures / half fails. nasty events. Hope they replace it for you.

I buy all my parts from either Excel Sports or The Colorado Cyclist. I doubt they were counterfeit.

As an aside, I’ve always been a Campy Record man until I upgraded both my bikes from their super reliable Record 10-speed to 11-speed.

The Campy Record 11-speed gruppo was crap. I never could get the rear shifting right on either bike. I finally gave up and replaced both gruppos with full Shimano Dura-Ace 11-speed gruppos. It took me all of 15 minutes to dial in the shifting on the Dura-Ace gruppos.

Only later did I learn when selling the Campy stuff to an out of the area Campy pro shop that there were recalls on their 11-speed gruppos because of poor shifting. I sold $6,000 worth of complete, nearly brand new gruppos for just $1,500.

Scott

 

[dadto2]

The narrower chains for 11 and 12 speed cassette wear out more quickly. I would get a chain stretch gauge if you haven't already, and replace the chains when they start to reach .75. I suspect you need a new cassette now.

 

[slo town]

The narrower chains for 11 and 12 speed cassette wear out more quickly. I would get a chain stretch gauge if you haven't already, and replace the chains when they start to reach .75. I suspect you need a new cassette now.

Thank you, good advice, but there is need for a new cassette. The cassette had the same mileage as the chain (about 1K miles). Also too, and no lie, I had just inspected and lubed the chain the day before the ride. Wear was only 0.25mm. Because DA cassettes and chainrings are so expensive I measure chain stretch every 2 or 3 weeks.

I have a great deal of mechanical awareness and sympathy and the chain skipped on the small cogs fewer than 4 or 5 times max, and that was done under light load as I crested and descended on the other side of an out of the saddle 16% 1/4 mile long climb that made me gasp for air (ugh). My first clue of a problem was when I heard a clicking noise in the drivetrain on the descent when I shifted into smaller cogs.

Like my cars, my bikes are hyper inspected and maintained. I have an extensive set of spares, including a half dozen BNIB Dura-Ace 11-speed cassettes. I even have a BNIB DA 52-36 180mm crankset, a BNIB spare set of brake/shift levers, BNIB spare derailleurs front and rear, plus two BNIB Campy Shamal Ultra wheelsets.

Heck, I even admit to licking my bikes clean after every ride - not exactly true, but close . Ramble…

Scott

 

[853okg]

I would absolutely counsel you to not use a KMC chain. That’s an unfortunate failure, but no cause for alarm yet. Stick with the Shimano chain.

 

[Pablo]

I would absolutely counsel you to not use a KMC chain. That’s an unfortunate failure, but no cause for alarm yet. Stick with the Shimano chain.

Just curious- why not?

 

[UG_Passat]

Looking at the crud on the chain, how often did you relube chain (and thus wipe away flushed out dirt and grime)?

I personally never had issues with KMC chains on SRAM and Shimano drivetrains.

The KMC missing links are reusable (not indefinitely), but enough that I can remove the chain and give it a deep cleaning and relube a few times

 

[853okg]

Just curious- why not?

 

[853okg]

The quality has nosedived. I have fixed bicycles professionally for over 45 years and hardly a day passes without me installing at least a few chains, and I’m often replacing KMC chains due to poor performance. Although this didn’t used to be the case, it has always been the case, at least since the invention of the uniglide chain that Shimano chains work best with Shimano drivetrains, and Dura Ace is the best.
I don’t mean to bash KMC. They’re nice people. But something is going on there, and even if it weren’t I wouldn’t put one of their chains on your Dura Ace bike.

 

[Number_35]

The quality has nosedived. I have fixed bicycles professionally for over 45 years and hardly a day passes without me installing at least a few chains, and I’m often replacing KMC chains due to poor performance. Although this didn’t used to be the case, it has always been the case, at least since the invention of the uniglide chain that Shimano chains work best with Shimano drivetrains, and Dura Ace is the best.
I don’t mean to bash KMC. They’re nice people. But something is going on there, and even if it weren’t I wouldn’t put one of their chains on your Dura Ace bike.

What's your opinion of SRAM chains? We have a sinle-speed, several 8-speeds, and a 9-speed in the fleet.

I've tended to use a mixture of Shimano and SRAM rear cassettes, and mostly Shimano or SRAM chains, with an occasional KMC or Wippermann chain.

 

[Pablo]

The quality has nosedived. I have fixed bicycles professionally for over 45 years and hardly a day passes without me installing at least a few chains, and I’m often replacing KMC chains due to poor performance. Although this didn’t used to be the case, it has always been the case, at least since the invention of the uniglide chain that Shimano chains work best with Shimano drivetrains, and Dura Ace is the best.
I don’t mean to bash KMC. They’re nice people. But something is going on there, and even if it weren’t I wouldn’t put one of their chains on your Dura Ace bike.

When did this start? You may have much more recent experience as I have not touch a new KMC speed chain in at least 3+ years.

 

[MRC01]

What's your opinion of SRAM chains? We have a sinle-speed, several 8-speeds, and a 9-speed in the fleet.
I've tended to use a mixture of Shimano and SRAM rear cassettes, and mostly Shimano or SRAM chains, with an occasional KMC or Wippermann chain.

Here's one data point: I've used Shimano and SRAM chains on my MTB which has 2014/2015 SRAM XX1 11-speed. Both work fine in terms of shifting, no apparent difference. Yet the SRAM XX1 chain lasts at least 4x longer than the Shimano chain, which was one of their upper end 11 speed MTB chains though I don't remember exactly which.

On the road bike I've always matched Shimano chains on Shimano drivetrains from 9 speed on up. The Shimano Ultegra/XT 9 speed chains have been great on our tandem. So far, I've got about 6000 miles on the Shimano Ultegra 11-speed chain on my road bike that still is not stretched. I keep them clean and lubed.

 

[slo town]

Looking at the crud on the chain, how often did you relube chain (and thus wipe away flushed out dirt and grime)?

I personally never had issues with KMC chains on SRAM and Shimano drivetrains.

The KMC missing links are reusable (not indefinitely), but enough that I can remove the chain and give it a deep cleaning and relube a few times

Are you serious?

Scott

 

[UG_Passat]

Are you serious?

Scott

Yes, dirty chains filled with crap will cause issues to the chain reliability