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Old 01-01-2019, 07:20 PM   #8
dmurphy
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Join Date: Dec 2017
Location: New Jersey
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Quote:
Originally Posted by Civicsman View Post
I’m not a metallurgist, but I don’t see evidence of internal failure. That is, don’t see any evidence of cracks, internal rust, etc. Haven’t seen any other reports of this failure, and I’ve been following SC since 2006.

Given that all six bolts failed, it would seem that the issue is specific to the individual machine. It is possible that some unusual process, such as hydrogen embrittlement or galvanic corrosion could be a factor. The hubs look corroded, but there is a lot of clean grey steel showing in the bolts, and 25 lb-ft isn’t that much torque. Occam’s Razor points to overtorque.

Maybe contact Segway about this. If I were Segway, I’d want to take a close look at those bolts, in case something is occurring over time in the field. If so, maybe they’ll send you some new hubs in exchange for your failed parts.


Questions: 1. How old is the machine? 2. Why are the hubs so dirty/corroded? 3. After snapping off one or two bolts, why did you proceed with the rest of them?
The machine is, I believe, 5 years old. I did buy it second hand, but it’s an SE model. That’s where the corrosion is from as well - it’s all surface rust. I believe (but could be wrong) this was a tour machine used in Greece. That’d explain some of the salt air surface stuff going on. Nothing that’d concern me about integrity, all just surface stuff.

The bolts snapped when I was taking it for a test ride after changing the tire. If it had happened when attaching, I’d absolutely have stopped.

I think I’ll reach out to Segway corporate since this seems so unusual. Consensus seems to be a complete gearbox replacement is necessary - even a machine shop wouldn’t be able to help - there’s not enough clearance behind the backer plate to install new studs without removing it from the gearbox itself. Just not enough depth.

I have a pair of used gearboxes on their way - hopefully they’re in good shape. We’ll find out the hard way. :-)
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