CityCyclingEdinburgh Forum » Questions/Support/Help

Dynamo maintenance

(5 posts)
  • Started 2 years ago by amir
  • Latest reply from LaidBack
  • This topic is not resolved

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  1. amir
    Member

    I have possibly a daft q related to dynamos.

    The wheel rim needs replacing, but I need to know whether the dynamo hub is in a state that justifies a rebuild. So how do you assess the bearings (not serviceable)?

    Background: My mechanic is new to dynamos, and had some concerns about how it was "centering itself between the high and low spots on the bearing races". But I showed him a newer Shimano dynamo and this seem even clunkier.
    The trouble is I never really bothered to see what the hub "felt" like when it was new, and all this could just be down to the magnets.
    The hub is an SP PV8 so the only way to service it is to send it to Thailand.

    Posted 2 years ago #

  2. steveo
    Member

    As I remember they're effectively disposable, the wire that runs from the rotating part to the fork is tiny and very delicate and almost always breaks when you open the hub.

    If it were for a commuter and backed up with battery lights I'd say its probably worth just building in to a new wheel but given your propensity to be riding at all hours, miles from city lights I'd be inclined to get a new hub, maybe get a cheap rim and use it to practice wheel building and have it as a spare.

    With the cogging caused by the magnets even new really good hubs feel like they're toast compared to a normal wheel.

    Posted 2 years ago #

  3. wingpig
    Member

    Having had my first duff hub in a while relatively recently the grating/scraping feel was nothing like the sort of controlled/damped stepped/lumpy feel of a fresh dynamo hub. My first dynamo outlasted two rims and was still working when it was eventually replaced because it was only 32h.

    Posted 2 years ago #

  4. amir
    Member

    Thanks for the useful views. I'll get the wheel rebuilt with the old hub

    Posted 2 years ago #

  5. LaidBack
    Member

    All hubs have lumpy feel when rotated.
    SON ones cost more but have less although SP ones also very good.
    If you switch front light on when using a SON the drag is very noticeable when rotated by hand but I look at it as fitness aid. I keep lights on all the time.

    My hack recliner bike has a hub that's 20 years old and interiors been rebuilt once by SON. Bearing went worn as was on our school run tandem. Rim still ok as had a Hope disc brake fitted in 2001. That was high tech back then.

    Since Bxt sending parts back to Germany for repair is not viable. Another bxt bonus. SON have replaced a hub that stopped working when only a year old. No company is perfect but alt least they took an interest.

    Posted 2 years ago #

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