How to improve connection to dynamo hub
 

My dynamo wheel has a Shutter Precision SP PV-8 hub. The wires simply insert into two holes on the outside of the hub, and I think Shimano hubs have a similar set up. The connection is not very secure, and the wires can pull out easily or get wet. The wires also tend to fray and get twisted out of shape when you have to remove the hub and reconnect them.

Is there a fitting that I could put on the ends of the wires to get a more secure connection, or another way to prevent the wires from fraying and twisting?

I've had a Shimano hub for about four years. The Shimano connector has the wires wrapped vertically around a center "plate" with channels for the wires, and an outer plastic shell that locks into the center plate. It looks like it should be a problem, but in practice, it hasn't been. I simply twisted each wire before closing the shell, and it's held so far.


If the SP hub has a similar arrangement, you might try stripping twice the length that's actually necessary, wrap the wire down and back, and then twist it around itself. If you think about it far enough in advance, you could solder the self-wrapped wire and use heat shrink tubing to hold the joint and insulate it.

Should Have Bought a Schmidt Hub instead? :innocent:

I had a Shimano hubs plug come loose many times , and the lighting cease.
I had made up the wiring with Bush & Mullers headlight twin lead... it was a rather loose fit ..

perhaps you can re do the plug with the 2 wires spliced in of a Larger Gage , perhaps even solid copper ?
so your plug slips on the hub tab with some mechanical resistance to pressing it on?




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Please post a picture. It sounds like you're doing something wrong. The only times my wires have come out were when I pulled, forgetting I had a wire to disconnect.

I'll try to post some photos over the weekend. However, here is a link to a website with a photo of the SP hub.

Shutter Precision Dynamo Hubs - Longleaf Bicycles

Are you removing just the wires or the whole connector?

You can leave the cable connected at the hub and use micro banana plugs in the cable along your fork leg where they're easier to reach and require less slack to accommodate disconnection.

sinewave cycles sells them for a few dollars a set including heat shrink

http://i.imgur.com/w327tpel.jpg

the SP/Shimano system is not problem free, but it's far better than the standard Schmidt. At least with the Shimano system you can do a field repair. Don't know what you do if you have the inevitable connector failure on a Schmidt while out on a ride. My biggest problem with wires is when I have a flat and I'm already a little flustered. I have a Schmidt connectorless system, but that's not a simple fix

Make sure the spade on the hub is pointing up? That way gravity helps keep the connector on.

What horror worst case scenario did you have in Mind? :foo:

the spade connector is a common electrical connector they use in auto wiring harnesses for Decades ..





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Upon further reflection, I've concluded that the problem I described is more of an annoyance than a serious problem. Although the hub connection is not very secure, the only times that it's caused a problem is when I have to remove the front wheel and/or transport my bike in my car. It still seems to me that some sort of plug or spade connector would be more secure than simply inserting the wires in a hole, perhaps there is a logical reason for the design that I'm not aware of.

the horror is ripping the wire out of the crimped connector when you are miles from anywhere. I might be able to Mcgyver a fix after I fix my flat, but it's just as likely that would be highly unreliable. I friend of mine has problems with his, I haven't ever asked him why. Last time I saw his bike, he had the wrong size connectors on it, I assume that was due to a wheel changing mistake. He really needs to upgrade to the connectorless system.

The connector is not a common size. You have to go to a specialty store to buy it. No automobile manufacturer uses this style of connector, and haven't for the last many decades.

You could 3d print a connector like the Shimano that would work the same, probably a good idea

Anecdotal sample of Just One " friend of mine has problems with his"

I have extra pieces shipped with the hub. if in fear mode, bring extras..


One time I did not have my hex bolt skewer quite tight enough .

but I had enough extra wire to the headlight it just wrapped around the axle once.

never failed electrically.

Extra wire is easy to cope with, for the pragmatic installation..




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Unless I'm completely misunderstanding, it sounds like you're doing it wrong. The part the wires are inserted into is a removable plug/connector. You should only have to insert the wires once then you can remove and reinstall the plug with the wires attached. I suggest you take another look at the manual to see how it works.

I agree with J.C. Take a look at this Shimano connector which yours is said to be based upon:

Shimano Dynamo Hub Connector - Longleaf Bicycles

Walk through the pictures to see how you fix the wires into the connector, then the connector just plugs into your hub.

My SP hub did not include a manual, or I wasn't provided one. I bought the entire Dynamo wheel from Longleaf Cycles, a custom build. However, after looking at the photos for the Shimano hub, perhaps I have not been connecting the wires correctly. I wasn't aware that the hub wiring connector snapped on and off, with the wires folded over it inside.

I have 10+ years on that shimano dynamo you describe. I insert the solid wire (not stranded) through the block and snap on the block. I also used heat shrink tubing to anchor stuff together. It never failed on me once and I ride rain or shine and all winter long in Chicago.

I just finished the same process on that same SP dynamo (new commuter build) and maybe over did the sturdiness (heatshrink + doubled-over wire so the block snaps quite snugly (bigly)). Many thanks to Drew for that bannana plug idea. I will add them so wheel removal is easier.

[adding: I also use heavier tires (schwalbe marathons) so I don't get flats. The old commuter never had a front flat in 10+ years. I only disconnected the dynamo once to do some brake maintenance and preemptively replace a worn out tire]

good catch on the OP using the connector wrong. There is a little piece of paper included with the hubs, they probably left it out of the box when they shipped the wheel.

I used to put dielectric grease in the connector, but I stopped because it's not really necessary.

Well, my lights quit working entirely while riding to work the other day. Fortunately I had an LED rechargeable light to use as a backup. I took a close look at the SP hub, and the connection is similar but not the same as the Shimano one. The wires do not fold over or lock in place inside the connection; they simply insert.

However, I got the lights working again. Apparently, the ends of the wires were just too twisted, dirty and corroded to make a good connection. I cut off the ends of the wires, stripped the insulation off the ends, and reinserted them in the connection. I also used a pencil eraser to buff the metal plates inside the connector. The lights front and rear were bright and shiny again with an easy spin of the front wheel.

I think that you're still doing it wrong, please read SP manual http://www.sp-dynamo.com/8-series-pi...stallation.pdf

hartsu

+1

See the shimano instructions too.
http://cycle.shimano-eu.com/media/te...9830600105.pdf
Stranded 22AWG wire, insulation trimmed back 16mm (SP says 14mm).

For a while I've been using the standard B&M wires which make the connector very secure. Often need to pry the connector off with a small screwdriver or knife.

Thanks for SP hub diagram. That helps a lot and let me actually see the problem. It is not easily apparent that the connector comes apart and was hard to separate even after seeing the diagram. However, I finally got it apart and wired correctly, so I should have no more problems.

Yeah, the Shimano connector has a grey plastic inner piece and a black outer piece but the SP is all black so it's less obvious it's supposed to separate.

You guys are the best! Perhaps I'll have a newfound appreciation for my dynamo light system now that it is wired correctly.

This leads to a significant point - push-on lugs and the SP wire-wrapping idea all depend on the wire being the right diameter, and on some kind of stiffener to keep the wire from vibrating too badly, fatiguing, and breaking eventually. The SON instructions seem to give limits, or at least SON gives you wire that is probably correct, and tells you how to do strain-relief. One of the other unknowns is getting a crimper that actually fits the lug and the wire.