Buggered my Shimano Dynohub

[yello]

It had to happen one day. Servicing my dynohub (which Shimano claims to be non-servicable) and I broke the copper cable. Pleased I am not.

What a bleddy stupid construction though. To get to the bearings you have to pull an electric connector apart - and there's a copper wire in there that is very fragile. 15000km and one buggered hub - all for the sake of a copper wire. Wrong sodding time of year too.

Moral of the story? Buy a Schmidt!

 

[Davidc]

Only thing is - you can treat the Shimano as a throw-away item compared to the Schmidt. Buy about 10 koreans for the price of a german!

I've never tried to strip either of my Shimano hubs down, the first has just gone on with no problem and is still running freely with no play after 6 years and 20000 miles. It's on its 3rd rim and 3rd bike now. The newer one is less than a year old and has only done 2000 miles so time will tell if I've just been lucky with the first one.

According to the Shimano information sheet you should be able to get spare parts for them, or you could buy a second hand one and canibalise it.

 

[yello]

It's the third time I've rebuilt it so I guess I can't complain too much.

Sadly, I'll not be able to get a spare for the broken bit as it's the copper wire that runs from the internals to the connector on the outside. I guess I could try taking it to an automotive place, see if they can solder an extra bit of wire on somehow....

To be honest, I'm considering not bothering at all and rebuilding the wheel with a standard hub... and running battery lights when needed in future. I don't do that many night time miles any more so it may be the most sensible option. A SON dynohub will set me back around £150... that's a lot of batteries!

 

[Davidc]

A SON dynohub will set me back around £150... that's a lot of batteries!

Yes, but a Shimano unit is only about £40.

Don't know what you have, but to get lighting to match the dynamo lighting on my touurer (with a CYO 60) I'd need to spend £90 on a Hope 1 so I still recon dynamo lights are at most equivalent cost.

I think that if one of my hubs failed now I'd probably get the basta bottle I have out and use it together with a good back up battery light, as the LED battery ones are so much better than battery lights used to be.

 

[yello]

Well, as it happens, I've just bought the newer Shimano dynohub (the 80, I had the 71) from rosebikes.

After looking at the prices, I decided it made sense as I have a Cyo as well. It's a brilliant set-up (literally!) that I preferably wanted to retain... I couldn't justify SON prices to do it. But reading around, it seems like the 80 is equally as good as the SON at nearly a third the price. Plus, I reckon I got unlucky with my hub - most people get better mileage out of the Shimano dynohub than I did. Fingers crossed for the new one!

I've decided to build a 2nd wheel too, and not ride the dynohub unless I need it, that will hopefully extend the life.

 

[yello]

Well, as it happens, I've just bought the newer Shimano dynohub (the 80, I had the 71) from rosebikes.

Strike that. Due to poor customer service, I cancelled the order and ordered the hub from ActionSports in Germany - cheaper too, at €56 delivered

 

[Davidc]

Good price.

I certainly wouldn't pay the asking price for the SON.

 

[yello]

No, me neither. £150+ for the SON... it can't be THAT much better surely??

 

[Davidc]

I looked at several reviews when I bought a new wheel for the tourer, complete with N30 dynamo, last January. The general view and test results analysis was that there's nothing much to choose between the N80 and the SON series, and that the N30 and N71 are not far behind. One french web site's review even put the N80 as better, but it was a french review of a german product! In everyone's tests the seals on the N30 weren't as well liked and it has slightly higher rolling resistance than the others with lights off. But then, it's a lot cheaper.

I'm going to have to service my older one (It was last done when a new rim went around it about 5000 miles ago) as it has slight play in the bearings. I'll be taking extra care with the connector wiring after reading about your experience.

 

[yello]

I looked at several reviews when I bought a new wheel for the tourer, complete with N30 dynamo, last January.

I did a similar exercise when I got my dynohub however many years ago it was and decided that, for my purposes, the SON just wasn't worth it. As you say, the SON was generally recognised as the better hub but there wasn't that much in it. Until I looked a few days ago, I didn't know about the N80... and then when I saw the reviews and prices, I decided I'd be daft not to get it. Especially when you consider that I needed a hub of some sort anyway to rebuild the wheel.

[quote name]I'll be taking extra care with the connector wiring after reading about your experience.[/quote]

I was really surprised when it snapped/broke. I thought I was being really careful; I wasn't even bending it where it broke. The wire snapped where the copper connector is soldered onto the wire. Perhaps I knocked it accidentally, I genuinely have no idea, but you do need to bend it through the connector plug body and perhaps there's only so much movement it'll take. I have a document (words and pictures) describing the overhaul if you're interested. I took it from a bike shop's website a few years ago but it's no longer there.

 

[andrew_s]

I have a document (words and pictures) describing the overhaul if you're interested. I took it from a bike shop's website a few years ago but it's no longer there.

http://forum.ctc.org.uk/viewtopic.php?f=5&t=12516#p365237

(just to save yello from the PMs)

 

[Davidc]

Thanks for that Andrew - much better pictures than the Shimano leaflet that came with the new one.

 

[KWolter]

Thanks for this good information!

After 9000 miles, I felt it was time to repack the bearings on my Shimano dynohub. Doing a search I soon found this posting and subsequently rebuilt my hub. It went very well, despite it being very difficult to keep the electrical connections from rotating when loosening the locknut due to that white sealer holding the two together. But I managed it. I'm glad I did the rebuild since I found three damaged ball bearings and the grease was dirty and had ground up (hardened) metal from the bearings in it. Fortunately, the bearing cups and cones were fine. People should be aware that Shimano often ships their hubs with the cones adjusted too tight and if used as shipped it doesn't take long for something to get damaged. I've had this happen with *three* of their hubs! Three balls in the dynohub and a cone in two different hubs... The dynohub is difficult to adjust because of the cogging of the magnets but it's possible, though tedious.

yello, sorry to hear about the wire breaking in your hub. From your description it seems to be an easy repair, for me at least. If you can find someone who is good with a soldering iron, it's just a matter of bridging the gap between the end of the broken wire and the brass piece. There may be an insulating coating on the wire that needs to be scrapped off before solder will stick. I even unsoldered the wire from the brass bit when I rebuilt mine to avoid having it interfere during the rebuild and resoldered it upon completion.