I recently went through the process of getting a warranty replacement for my SON dynamo hub due to bad (worn or corroded?) bearings. At the time I was dealing with the problem I couldn’t find much information about anything similar, so I figured I’d post my experience here for anyone else who needs to hear it.

SON hubs are known for being extremely reliable, which is why I chose one for my new Chumba Stella bikepacking rig in 2022. This bike was a big step up and a major splurge, and I figured what the heck, may as well get the dynamo hub while I’m at it. I enjoy long remote tours and dabble in bikepack racing, so I figured it would serve me well.

My hub is a SON 28 15 110 (Boost), and it powers my kLite Ultra light and charging system. Overall I’m extremely happy with this setup, especially for bikepack racing and the many hours of night riding that come with it. These hubs are a long-time favorite of long-distance bike travelers, so it seems I got unlucky. I’m not the only person to experience this problem, as I’ll explain down below, but it’s since been resolved in current production hubs.

My goal here isn’t to knock SON hubs or discourage others from choosing them. Rather, I’m sharing my experience to help anyone who might be in a similar predicament. I was in the middle of a remote tour in Morocco when my bearings really went south, and it was a bit stressful. I would have loved a post like this to help me understand what was happening and what I could do. Happily the warranty process was smooth and I had a new hub waiting for me when I got home, which is now working great.

First Hints of the Problem

Looking back, the first hint of the problem arose during my Western Wildlands section ride in southern Idaho, Utah, and northern Arizona. I had about 3000 miles on the hub so far, mostly bikepacking in the USA and Central Asia on a mix of gravel, rough dirt roads, and trails. The hub had seen some rain and a few creek crossings, but to my knowledge hadn’t ever been fully submerged.

The earliest symptom: after a day of not riding I noticed that my wheel felt oddly hard to spin. Once I pushed through the resistance and got it spinning freely, it seemed good as new. I finished that ride, about 1200 miles, with no further issues except occasional light resistance when spinning the wheel first thing in the morning.

Progression

After returning home from that trip I completely forgot about the problem. My bike mostly sat in the garage through one of the rainiest California winters in recorded history. In March, as I started prepping for a trip to Morocco and Portugal, I swapped the wheel over to my Fargo and once again noticed the resistance when spinning the wheel. Too late to do anything about it now – oops! As long as I spun the wheel a bit, it was fine, so I packed up the bike and flew to Marrakesh.

Upon unpacking my bike in Marrakesh I was alarmed to find that my SON dynamo hub had locked up almost entirely. It took a fair bit of force to get the wheel turning again, but once I spun it for awhile it moved freely. I spent a lot of time nervously test-spinning the wheel in the courtyard of our riad, trying to pretend it was fine (it mostly was). Perhaps in denial, and with no better ideas, I started the trip.

At this point it had been well over a thousand miles since the first signs of the problem. As long as I was riding daily the hub never locked up again, but the problem did progress. Spinning the wheel while on the bike sounded grinding and irregular. When turning it by hand with the wheel removed from the bike there was a gritty feeling and a gritty sound.

Dynamo hubs always have a discreet “notchy” feel and unique sound, but mine was obviously worse than usual. It’s normal to feel like the hub wants to snap into discreet positions as it turns, but it should do so smoothly, mostly quietly, and uniformly around the entire revolution. My husband also has an identical SON dynamo hub on his bike (fewer miles on his, but so far no sign of similar problems) and his felt and sounded much better by comparison.

The other symptom was increasingly obvious bearing play. It’s hard to quantify the amount, but when pushing the wheel side-to-side while on the bike there was obvious wiggle back and forth. With the wheel off the bike I could move the center back and forth and actually hear a squeaking sound inside.

As we navigated some incredibly rough, rocky, and sandy desert roads in Morocco, I developed a nervous habit of checking my wheel for bearing play at every stop. Was it getting worse? Maybe just a little…? I knew there wouldn’t be an easy way to deal with the problem while in Morocco, so we simply finished our route. Thankfully the hub held up and didn’t really cause any problems, other than stressing me out.

Throughout this whole period I was using my kLite USB charger (but not the light) to top up my power banks. I didn’t notice any chance in the hub’s ability to generate power, though we were riding relatively short daily distances on slow terrain so the charging output wasn’t great anyway.

Once in Portugal on smoother roads, it seemed that the hub stopped getting worse. I figured I could limp through Portugal but worried about what to do once home, since I had some bikepacking races coming up soon. At this point I started researching how to get the hub fixed or replaced.

Making the Warranty Claim

SON hubs come with a five year warranty. I had put about 5000 miles on my hub in just over a year, and while that’s a fair amount of riding it’s not crazy by bike travel standards. SON hubs are known for their reliability and loved by long-distance bike travelers, so I figured this amount of wear couldn’t possibly be normal. Time to get in touch and see what could be done.

I live in the United States and my hub was purchased there, so I emailed Peter White Cycles, the official US distributor for German “Schmidt’s Original Nabendynamo” (SON) hubs. Linda White responded immediately and helpfully, asking for some information and a video showing the bearing play as best I could.

The old hub needed to be cut out of my wheel before sending, and I was currently in the middle of a tour in Portugal. I figured it would be cheaper and easier to have a bike shop cut out the old hub at the same time they laced in the new one, so I opted to pay for my replacement and then get a refund later.

The old hub, to its credit, survived that entire trip (about 1200 miles) without causing any practical issues. And I have to thank Linda at Peter White Cycles for her calm and helpful communication, which made the whole process much less of a headache than it could have been.

About the Author

Hi there, I’m Alissa, founder of Exploring Wild. I’ve traveled over 19,000 miles by bike and still can’t stop planning my next ride (and helping you plan yours). Pavement and panniers or singletrack and seat bag, I love it all. On my bike I feel free. Learn more about me here.

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The post My Experience With Bad Bearings in a SON Dynamo Hub (Successfully Replaced, So Far So Good) appeared first on Exploring Wild.