Yet Another Cycling Forum

General Category => The Knowledge => Topic started by: T42 on 09 September, 2019, 08:54:10 am

Title: SON dynamo service
Post by: T42 on 09 September, 2019, 08:54:10 am
Chum of mine has a SON dyno wheel that grates when he rotates it.  He used it on PBP 2011 so it's at least 8 years old.

He's asking me if he should try to service the bearings himself. Sending it back to SON is likely to be a royal PITA and cost as much in the end as new kit.

What thinketh the panel?
Title: Re: SON dynamo service
Post by: Brucey on 09 September, 2019, 09:31:12 am
it is probably grot inside the generator that is making the noise, e.g. bits of rust between the stator and the magnets. The bearings could be fine.

You don't say what model of hub he has but there is one that is easy (ish) to service; the innards unscrew from the RH side. However all the other SON models are pigs to work on.

If you want a SON then a factory service will make the old hub like new and at that price it would be very cheap for a new SON hub. However you can buy an alternative ( cheaper, less good) hub for about the same money.

cheers
Title: Re: SON dynamo service
Post by: T42 on 09 September, 2019, 09:48:50 am
Thanks, Brucey.  I don't know what model he has - come to that, I'd be hard put to remember which I have.

Anyway, I'll pass it on. Ta.
Title: Re: SON dynamo service
Post by: Ian H on 09 September, 2019, 09:59:21 am
It cost about £64 to have my old black-barrel one serviced and returned via SJS.  It now even has a breather hole inside the hollow axle.
Title: Re: SON dynamo service
Post by: T42 on 09 September, 2019, 10:31:54 am
Just checked mine (model #K179) - still silent and developing 8.5v when I spin it by hand. 12 years old with 8 of service.

ETA Thanks, Ian H - duly passed on.
Title: Re: SON dynamo service
Post by: pdm on 09 September, 2019, 12:18:10 pm
IMHO, don't service it yourself. I have 3 SON 28s that have done many miles. about 3 years ago, one developed slight loosening/roughness of the bearings after 5 years of very heavy use - sent it off to SON and got it back as good as new free of charge! I would have gladly paid the £64 for the years and distance it had given me nonetheless...
Title: Re: SON dynamo service
Post by: Wowbagger on 10 October, 2019, 04:13:06 am
Mine is 13 years old, has done almost 39000 miles and has had to put up with my great bulk, which has been in excess of 105 kg for all of that time, and 10kg more than that for most of it. I have been advised not to get it serviced until it shows signs of deterioration.
Title: Re: SON dynamo service
Post by: rower40 on 10 October, 2019, 05:18:23 am
Dearly beloved,

We are gathered together to give thanks for this wonderful item of engineering, which lighteth our way, yea verily, e'en when all batteries have shuffled off this mortal coil...
Title: Re: SON dynamo service
Post by: Brucey on 10 October, 2019, 10:19:37 am
Just checked mine (model #K179) - still silent and developing 8.5v when I spin it by hand. 12 years old with 8 of service.

IIRC ~K179 is the Stvzo approval number, rather than the model number per se.  The ~K number does vary with the model though, since each (electrically) different generator needs a separate approval.     Is yours a 28 Klassik?

(http://www.sjscycles.com/supersize/18614.jpg)

If so this is one of the few that can be opened up without undue difficulty.  Using the appropriate tool all the gubbins unscrews from the RHS.

After a certain date all SON models have their 'pressure compensation system' which comprises a long coiled plastic vent tube connected to a drilling in the axle. The basic idea is that  water can't into the hub through the vent, even though the air volume in the hub is contracting and expanding with changes in temperature.  If you send an older SON in for a factory service (outside the five year(?) warranty period) they can upgrade the hub to the newer style vent.


cheers
Title: Re: SON dynamo service
Post by: rogerzilla on 10 October, 2019, 04:28:56 pm
Chuck it and buy a Shimano one  :demon:
Title: Re: SON dynamo service
Post by: Wowbagger on 10 October, 2019, 10:47:30 pm
Dearly beloved,

We are gathered together to give thanks for this wonderful item of engineering, which lighteth our way, yea verily, e'en when all batteries have shuffled off this mortal coil...

The key question is - does a SON dynamo have an immortal coil?
Title: Re: SON dynamo service
Post by: Paul on 10 October, 2019, 11:23:17 pm
Dearly beloved,

We are gathered together to give thanks for this wonderful item of engineering, which lighteth our way, yea verily, e'en when all batteries have shuffled off this mortal coil...
... In the name of going farther and of the SON and of the oily spirits...