After receiving over 4,500 incident reports, Shimano has announced a voluntary recall of Hollowtech II road cranksets produced between 2012 and 2019 for a possible bonding separation issue in North America. That includes two generations of the popular Ultegra and Dura-Ace cranksets totalling 760,000 cranksets, and over 2.8 million are affected worldwide. In the UK and Europe, Shimano has instead issued an "inspection and replacement program" rather than a full recall.
For many people, the delamination, or separation, of Shimano Ultegra and Dura-Ace cranksets won't come as news. In fact, we covered the issue back in 2021, when Shimano denied any problem with the design.
“During our examination of usage cases, and through our own internal testing, we have not identified a design problem with the cranks, and we are continuing our investigation to discover other factors or causes,” the company said at the time.
It would appear that this investigation has now brought an issue to light as today Shimano has issued a "Voluntary Inspection and Replacement Recall Notice" for selected bonded 11-speed Hollowtech II road cranksets that were produced between 1 June 2012 and 30 June 2019, for what it describes as a "possible bonding separation issue".
The affected products are Dura-Ace and Ultegra branded cranksets with the following model numbers: Ultegra FC-6800 and FC-R8000, and Dura-Ace FC-9000, FC-R9100, and FC-R9100-P. You can find the product code stamped on the inside of the crank arms at the pedal end.
Shimano points out that not all 11-speed Hollowtech II road cranksets are part of the recall and that only those produced during the specified period need to be inspected.
"We expect only a very small percentage of these cranksets will need to be replaced," Shimano said.
Customers have been advised to follow Shimano's online 'Crank Identification and Inspection Process', visit bike.shimano.com, or visit with an authorised Shimano retailer. The company says that inspections will occur at Shimano authorised retailers, and any crankset that does not pass the inspection process will be replaced free of charge.
The document goes on to say that "the replaced crankset will be a special version, which may feature a different cosmetic appearance while maintaining the same level of performance."
The recall also states that if your crankset passes the inspection and has no signs of delamination, then you can "continue to enjoy your ride. Have your bike tuned up and inspected regularly, ask your dealer for recommendations based on your riding habits. Pay attention to changes in the sound and feel of how your bike is riding."
Given the number of comments, blog posts, and indeed broken cranksets that we've received over the years, we're confident in saying that the problem is widespread.
At the time of writing an official recall only applies to the USA and Canada, where 760,000 cranks were sold. This can be found on the United States Consumer Product Safety Commission website.
The situation is different in the UK and Europe, as Shimano Europe has not officially announced a recall, rather an "inspection and replacement program" where Shimano "will have any applicable crankset inspected".
A statement on Shimano's EU website acknowledges that the “safety and inspection and replacement programme” also affects riders in the EU and that “the timing of the inspection and other details will be announced on this website in the near future”.
We'd better ride carefully until then!
road.cc has sent off multiple cranksets to laboratories to be investigated as part of our own study, with our early findings concluding so far that an essential preliminary stage in the failure of the cranksets is the partial debonding of the inner and outer U-shaped channels that together make up the rectangular tube section of the crank arm.
When satisfactorily bonded the section is of adequate strength to resist any loads that it commonly sees. However, if partial debonding occurs between the parts, the upper/inner channel is vulnerable to the size of loads that may commonly be applied during use.
No conclusions, however, have yet been made concerning how debonding between the two U-shaped channels initiates. Flaws resulting from the manufacturing process, environmental deterioration, and fatigue have all been considered as possibilities. Whichever is at fault, such partial debonding of the two channels is a notable weakness that might eventually lead to gross failure.
Any proposed solution to the problems noted by us in our study will depend on how frequently failures occur. If rarely, then this might be considered acceptable by the manufacturer. If it is a frequent problem (and a list of 4,500 incidents in North America alone seems fairly frequent to us) the recall of the product, like Shimano have just initiated with the Hollowtech IIs, and a redesign will be necessary.
Have you been affected by the delaminated cranks? And do you think Shimano should have acted sooner? Let us know in the comments section below...
Jamie has been riding bikes since a tender age but really caught the bug for racing and reviewing whilst studying towards a master's in Mechanical engineering at Swansea University. Having graduated, he decided he really quite liked working with bikes and is now a full-time addition to the road.cc team. When not writing about tech news or working on the Youtube channel, you can still find him racing local crits trying to cling on to his cat 2 licence...and missing every break going...