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hilltowner 10-17-19 12:32 PM

What's realistic to expect regarding dynamo hub damage repair
I messed up my Shutter Precision SP-8 dynamo hub when a stray elastic tie-down got caught in the spokes and wrapped itself around the hub popping & cracking the ring that holds the contacts for the hub wiring.

Is it realistic to think this is repairable by someone with no expertise? I sent off a query to SP in Taiwan to see if they even sell replacement rings. Anyone out there have any experience dealing with similar situations?

pdlamb 10-17-19 12:48 PM

I wish you luck with SP. Looking at the picture, I'd think optimistic realism might include a discount on a replacement hub. It'll then cost almost as much to rebuild the wheel as it would to buy a new wheel. :(

unterhausen 10-17-19 01:11 PM

that's too bad. I suspect you could do something with epoxy and unwaxed dental floss, but we don't have the complete picture.

Please let us know what SP says

hilltowner 10-20-19 08:21 PM

SP was very quick to respond and the upshot is they recommend (actually there is no second option) sending the hub to them for "bearing replacement." A follow up email clarified the actual process which is "...The bearing replacement is not just only for fixing bearing, but also checking the whole hub. If we find something wrong with the bearing, we will replace it to a new one..." The price is TWD $100 or at current exchange rates about USD $33. The only wild card will be the shipping cost. I can only send them the hub so the wheel will need to be disassembled.

I've ordered a new SV-9 (a later generation which is lighter and improved) and will lace that into the rim which is only 3 years old and not showing any signs that it needs retirement. Since I've got to take the wheel apart anyway I might as well do that. If the shipping cost doesn't make the repair of the old hub ridiculous, I'll send that off and get back a reconditioned spare that I can decide what I'll do with, to either keep or sell.

Oddly enough, with the way the hub was in the picture, it did not power the light. I wanted to continue riding and decided for better or worse to get the ring back to its original position. After much wrestling and further damage to the ring I got it back there. To keep the female lead from just dangling I reconnected it to the male connector on the ring and lo and behold the light is back to full power when the hub turns. I suppose some plumber's goo or silicone sealant might make it more waterproof but the new hub is due to arrive in a few days and when cold weather really gets here I'll rebuild the wheel.

It was an expensive mishap but I'm getting out cheaply compared to what a new wheel on the same kind of rim with a Schmidt SON hub would have cost from Peter White Cycles. I asked PWC if they would build up a wheel with a buyer-supplied SP hub instead but haven't received a response and, at this point, don't expect to.

noglider 10-21-19 09:19 AM

That sounds reasonable. I hope it works out.

unterhausen 10-21-19 10:12 AM

I'm sure Peter White does a good job building wheels, but he's far from the only wheelbuilder out there.

unterhausen 10-27-19 11:25 AM

did you see this thread:

Sure looks like you should be able to fix your hub yourself. Still require some glue.

CliffordK 10-27-19 12:59 PM


The first thing I would do is disassemble it enough that you can get to the wires/terminals.

Then attach either a voltmeter, or your lights, lock it in a truing stand, and give the wheel a spin.

Is it generating?

If all you need is a little plastic ring, I'd talk to SP (or a local dealer) about just getting the part you need. Much easier than 2-way shipping and disassembling a wheel.

Or, ask a couple of dealers if they have some damaged hubs that might have the part you need.

hilltowner 10-27-19 07:55 PM

It's back to powering the light after wrestling the ring back to its original location. It's cracked though and unlikely to seal out water from entering the hub. I think a bearing replacement wouldn't hurt its operation however. The link sent by @unterhausen, which shows the bearing replacement process, shows the steps being just barely within my ability level but locating a new plastic ring seems difficult since SP doesn't appear to want to sell them as separate replacement parts.

Tourist in MSN 10-27-19 09:08 PM

I cracked that plastic ring on one of my SP hubs, but on the other side where the wiring was not involved, I could not see any wire at all. I shoved something in there that hardened up, I Shoe Goo that I shoved in there, but it might have been Seam Grip, both of which are liquids that will harden and solidify. You can hardly tell that I did anything to fill the hole.

Your repair could be trickier, as plugging and unplugging the wiring connection could put stress on your repair. And if you do not seal it up well, it gives water an opportunity to get into the armature of the hub.

Good luck with whatever you do.

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