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Road Racing

DT Swiss acknowledges Ratchet EXP hub problems in new service bulletin

Affected rear hubs can spontaneously freewheel in both directions.

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DT Swiss hubs have an enviable reputation for reliability thanks to the superb design and engineering of the brand’s star ratchet freehub mechanism. But now that the patent has expired and several other hub companies have adopted the system for themselves, the Swiss brand had little choice but to switch to something better. According to DT Swiss, the new Ratchet EXP system is not only lighter, but it also improves bearing durability and is easier to service. 

Sounds good, right? DT Swiss was obviously banking on its new Ratchet EXP system being just as reliable as the old design. Except that it isn’t — at least intermittently, anyway. Numerous reports from consumers have appeared online describing how their new Ratchet EXP rear hubs have started freewheeling in both directions, which, needless to say, isn’t good.

DT Swiss’s older star ratchet driver mechanism is shown at the bottom, while the newer Ratchet EXP is up top. One of the key differences is that the newer system only has one spring and one moving ratchet, whereas the older setup has two. Photo: DT Swiss.

After quietly taking care of affected customers for the past few weeks, DT Swiss recently acknowledged the issue publicly with a service bulletin. Included in that bulletin is the following:

With the introduction of the new EXP Technology, DT Swiss built on the 25 years of star ratchet technology to bring a product to the market that further evolves around the idea of reliability and engagement precision.

It is precisely this high level of precision that requires a correspondingly high level of precision in the design, production and assembly of its single components. Although we follow standardized and rigorous quality assurance and control processes in the production of these single parts, we experienced some unusual service cases of the new Ratchet EXP System that we could not immediately explain.

In-depth material and product analysis lead us to the conclusion that variations in the surface finish of the ratchets that are in a completely normal range for the traditional and established systems are potentially leading to premature abrasion of wear parts in the new Ratchet EXP system. This premature wear can then lead to restrictions of the engagement in individual cases, which can be remedied by a simple replacement of those wearing parts.

With the further development of the production and quality assurance management we were able to even further narrow down the variance within the surface quality. This will ensure that you will experience the very same level of engagement reliability and product durability that you are used to from DT Swiss.

We understand that your expectations of the quality and reliability of DT Swiss products is very high, so is our own expectation towards our products. We also understand your disappointment if this premature wear has affected your riding experience by any means. We want to sincerely apologize for that.

The service bulletin goes on to suggest that you contact your local DT Swiss service center “for a free inspection and service of the product if needed.”

What’s curious here — and what was likely perplexing to DT Swiss, too — is that the failure mechanism is only affecting the newer Ratchet EXP hubs, not older star ratchet ones, despite the fact that they operate on very similar principles. In both designs, spring-loaded ratchet rings slide axially within a toothed housing. But where there are two sliding ratchets in the older design, Ratchet EXP only has one; the other is fixed in place. 

The old DT Swiss star ratchet system is legendary for its overall reliability and ease of service. Performing basic maintenance often doesn’t even require any tools.

DT Swiss says that some sort of unexpected interference is occasionally causing the Ratchet EXP rings to bind within that toothed housing despite the fact that they’re manufactured using the same processes as the older star ratchet rings and have identical surface finishes. 

“By examining the ratchets with an electron microscope, we were able to identify these surface irregularities in the nanometer range and trace the failures back to them,” said DT Swiss product manager Nils Verhoeven. “We then immediately intervened in the ongoing production and established an operation in the manufacturing process to narrow down the allowed tolerances to ensure the necessary precise surface finish for the Ratchet EXP system.”

DT Swiss is in a tough spot. While its star ratchet system is incredibly simple and reliable, the patent recently expired, and a growing number of competitors have adapted the design for themselves. This one is from popular Taiwanese OEM supplier KT, but there are countless others.

Verhoeven also provided more detail as to how DT Swiss is repairing affected wheels. 

“We replace all possible wear parts of the freewheel system as a precautionary measure, even if the wheel/hub is almost as good as new. In our service centers, we have already stocked up accordingly, so that we can meet usual service times of 2-5 working days even within the starting season. If the customer has not had a problem with the freewheel system, which will be the majority, we will replace the moving ratchet, freewheel body, spring, and grease. If the customer has already experienced a restricted engagement with his hub, we will also replace the ratchet thread ring [which resides inside the hub shell – ed.] as well as the bearing.”

Warning signs and what’s affected

According to Verhoeven, affected hubs will likely display some telltale symptoms before a complete failure occurs.

“Since the irregularities in the surface finish of the ratchet primarily cause premature wear, it is most likely that delayed engagement or noise will occur before the sprocket gets stuck in the freehub body.” 

In other words, if you have a rear wheel with a Ratchet EXP driver, it’s a good idea to pay a little closer attention to how well it’s working, and to the sounds it’s making. If you notice something to be even a little bit off, it’s probably best to play it safe and contact DT Swiss for guidance.

In the new Ratchet EXP system, the drive ring in the hub shell is now fixed in place, while the other ratchet ring slides axially inside the freehub body. The tolerances are quite tight, however, and some users have been having issues with the ratchet ring binding up inside the freehub body. At that point, the teeth no longer engage, and the hub then freewheels in both directions.

As for what hubs are affected, though, the situation is a bit murky. 

In the official service bulletin, DT Swiss only lists its own Ratchet EXP hubs and wheels, along with a production date code that identifies products that were manufactured using the original processes. However, the Ratchet EXP driver mechanism is also featured on a wide range of OEM wheelsets from other brands, such as Bontrager and Roval. As a result, shouldn’t any issues affecting DT Swiss hubs with the Ratchet EXP driver mechanism also affect third-party brands that use the same guts?

“We are in contact with all OEM as well as ASM [all sales manufacturing — ed.] customers and inform them in detail about the situation,” Verhoeven said. “In addition, we check individually how we can support our business customers and take possible measures together to ensure the satisfaction of our customers, dealers, and ambitious cyclists.”

So is that a yes? Seems a bit unclear.

This isn’t technically a DT Swiss hub, but it still uses Ratchet EXP internals. So might this be affected, too? Hard to say.

A most unwanted hiccup

The original star ratchet hub design from Hügi — the German company that DT Swiss purchased more than two decades ago — used a single sliding ratchet ring and spring before switching to the more robust double spring setup that earned DT Swiss that reputation for reliability. But in trying to stay ahead of the game after the patent expired, DT Swiss may have inadvertently reverted back in some ways to that older, and less bulletproof, design. Only now, it doesn’t have the option of just tossing in another spring like it once did.

Ultimately, my guess is that DT Swiss will weather this storm and come out the other end, albeit with a few bruises to show for it. Now that the problem has been identified, it’ll be easier to fix. However, the long-term damage may be far more impactful. 

DT Swiss was certainly hoping that the new Ratchet EXP system would be just as reliable as the old star ratchet setup, but it’s off to a bit of a rocky start.

DT Swiss is so commonly found in OEM wheels largely because of its reputation for reliability, and however widespread this issue is, the company had better make it priority number one to fix it once and for all. After all, why develop your own hub in-house if you already have a willing partner you (and customers) know that you won’t have to worry about down the road? 

Fingers crossed, if only for DT Swiss’s sake, that this really is a blip. Because unfortunately, reputations for reliability are a lot like trust: they’re hard to earn, easy to lose, and brutally difficult to earn back. 

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